Maryland Department Of Natural Resources
Resource Assessment Service
MARYLAND GEOLOGICAL SURVEY
Recent (1988-1995) Maryland Shorelines with Erosion Rate Attributes

1. Identification Information

1.1 Citation
8.1 Originator: Maryland Department of Natural Resources, Chesapeake Bay & Watershed Programs, Resource Assessment Service, Maryland Geological Survey (MGS)
8.2 Publication Date: 2003
8.4 Title: Recent (1988-1995) Maryland Shorelines with Erosion Rate Attributes
8.5 Edition: 1
8.6 Geospatial Data Presentation Form: vector digital data
8.8 Publication Information
8.8.1 Publication Place: Baltimore, Maryland, USA
8.8.2 Publisher: Maryland Department of Natural Resources, Chesapeake Bay & Watershed Programs, Resource Assessment Service, Maryland Geological Survey (MGS)
8.9 Other Citation Details: CD-ROM CoErosionRates
8.10 Online Linkage: http://www.mgs.md.gov

1.2 Description
1.2.1 Abstract:
In 2000, the Maryland Geological Survey (MGS) was awarded a Coastal Zone Management grant to complete the acquisition of a recent (ca. 1990) digital shoreline for the coastal regions of Maryland -- the Chesapeake Bay, its tributaries, the coastal bays, and the Atlantic coast. MGS contracted the services of EarthData International, Inc. (EDI), currently of Frederick, Md., to extract shorelines from an existing wetlands delineation, which was based on photo interpretation of 3.75-minute digital orthophoto quarter quads (DOQQs). In areas where a wetlands coverage was not yet available, EDI interpreted shorelines directly from the orthophotography. DOQQ registration (Maryland State Plane Coordinate System, NAD 83, meters) was transferred automatically to the shoreline vectors. Following shoreline extraction or interpretation, EDI assigned attributes to the vectors based on shoreline type: beach, vegetated, structure, or water’s edge. All four categories are linear features, except “beach,” which, if sufficiently wide, can be both linear and polygonal. Shorelines were merged into 7.5-minute quadrangles, provided that the aerial photography on which the DOQQs were based was flown in the same year.
MGS used the shorelines to create a series of Shoreline Changes maps. In doing so, MGS erased the landward edge of beach polygons, leaving the seaward edge intact as a linear feature.
The Geographic Information Services Division of the Maryland Department of Natural Resources (DNR) merged the shorelines for all of the 7.5-minute quadrangles into a single, statewide coverage.
MGS, working collaboratively with Towson University’s Center for Geographic Sciences (CGIS), subsequently used the recent shorelines, along with historical ones, as input into a U.S. Geological Survey (USGS) program, the Digital Shoreline Analysis System (DSAS) (Danforth and Thieler, 1992; Thieler and others, 2001). DSAS determines linear rates of shoreline change (erosion or accretion) along closely spaced, shore-normal transects. Based on DSAS output, the collaborators assigned the following erosion rate categories as attributes to the recent shoreline, clipped by county from the statewide coverage:

- High erosion rate (more than 8 ft/yr)
- Moderate erosion rate (4-8 ft/yr)
- Low erosion rate (2-4 ft/yr)
- Slight erosion rate (0-2 ft/yr)
- No change
- Accretion
- Protected
- Unknown
- No Data

The data set contains recent shoreline vectors for sixteen coastal counties and Baltimore City (see Appendix 1), assigned both shoreline type and erosion rate attributes. The vectors represent shoreline positions between the years 1988 and 1995.
The metadata was originally written to document the recent shoreline vectors, interpreted, directly or indirectly, from DOQQs and merged by 7.5-minute quadrangle (see Appendix 2). It was amended to include information about the erosion rate attributes later assigned to the county shorelines.

1.2.2 Purpose: This data set complements a set of historical digital shorelines for the Maryland reaches of the Chesapeake Bay, the coastal bays, and the Atlantic coast (See Section 1.14). That data set spans the period 1841-1977. The two data sets are being used to update a series of Shoreline Changes maps and to determine coastal land loss during the last half of the 20th century. Other State agencies will be able to use this data to analyze and update land loss information, analyze historical erosion trends, and assess the extent and magnitude of shore erosion on a regional geographic basis. In particular, the availability of up-to-date shoreline change data will support the design and implementation of shore protection projects and the development of a comprehensive shore erosion control plan.
1.2.3 Supplemental Information: This document serves as metadata for recent (ca. 1990) shoreline vector files, assigned erosion rate attributes, for Baltimore City and 16 coastal counties in Maryland.

See appendices:

Appendix 1: Bounding Coordinates of Maryland’s Coastal Counties and Baltimore City

Appendix 2: Shoreline Dates, by Quadrangle

Appendix 3: Constituent Quadrangles and Attributed Shoreline File Size, by County

#### Related publications:

Hennessee, L., 2000, Acquiring a modern digital shoreline for Maryland from recent (1988-1995) orthophotography: Maryland Geological Survey, Baltimore, Md., Coastal and Estuarine Geology File Report No. 00-7.
Hennessee, L.H., Valentino, M.J., Lesh, A.M., and Myers, L., 2002, Determining shoreline erosion rates for the coastal regions of Maryland (Part 1): Maryland Geological Survey File Report No. 02-04, Baltimore, Md., 32 p.
Hennessee, L.H., Valentino, M.J., and Lesh, A.M., 2003, Determining shoreline erosion rates for the coastal regions of Maryland (Part 2): Maryland Geological Survey File Report No. 03-01, Baltimore, Md., 53 p.
Hennessee, L.H., Valentino, M.J., and Lesh, A.M., in prep., Updating Shore Erosion Rates in Maryland: Maryland Geological Survey File Report No. 03-05, Baltimore, Md.

#### References:

Conkwright, R.D. (compiler), 1975, Historical Shorelines Atlas: Maryland Geological Survey, Baltimore, Md., 4 volumes.
Cowardin, L.M., Carter V., Golet, F., and LaRoe, E., 1979, Classification of wetlands and deep water habitats of the United States: U.S. Fish and Wildlife Service, 103 pp.
Danforth, W.W., and Thieler, E.R., 1992, Digital Shoreline Analysis System (DSAS) User’s Guide, Version 1.0: U.S. Geological Survey Open-File Report 92-355, 18 p.
Hennessee, L., 2000a, Metadata: Historical shorelines, 1841-1976, Chesapeake Bay region of Maryland (CD-ROM SCSL_RVC): Maryland Geological Survey, Baltimore, Md.
Hennessee, L., 2000b, Metadata: Maryland digital shoreline acquisition from recent orthophotography: Recent (ca. 1990) shorelines, coastal regions of Maryland (CD-ROM RecentSL): Maryland Geological Survey, Baltimore, Md.
Thieler, E.R., O’Connell, J.F., and Schupp, C.A., 2001, The Massachusetts Shoreline Change Project: Technical Report 1800s to 1996, U.S. Geological Survey Administrative Report, Woods Hole, MA.

1.3 Time Period of Content
9 Time Period Information
9.2 Multiple Dates/Times
9.2.1 Calendar Date
9.3 Range of Dates/Times
9.3.1 Beginning Date: 19880417
9.3.3 Ending Date: 19950325 – See Appendix 2 – Date of photography
1.3.1 Currentness Reference: The dates on which aerial photography was flown. The aerial photography was used to create digital orthophoto quarter quads (DOQQs). A wetlands delineation based on photo interpretation of the DOQQs or the orthophotography itself was the immediate source of the shorelines in the data set.

1.4 Status
1.4.1 Progress: Complete
1.4.2 Maintenance and Update Frequency: Irregular

1.5 Spatial Domain
1.5.1 Bounding Coordinates
(Bounding coordinates of entire study area; see Appendix 1 for bounding coordinates of individual counties)
1.5.1.1 West Bounding Coordinate: -77.375°
1.5.1.2 East Bounding Coordinate: -75.0°
1.5.1.3 North Bounding Coordinate: 39.625°
1.5.1.4 South Bounding Coordinate: 37.875°

1.6 Keywords
1.6.1 Theme
1.6.1.1 Theme Keyword Thesaurus: Global Change Master Directory List of Valid Keywords: Earth Science Parameters Valid Keywords (CATEGORY > TOPIC > Term > Variable) http://gcmd.gsfc.nasa.gov/valids/
1.6.1.2 Theme Keyword: EARTH SCIENCE > OCEANS > Coastal Processes > Beaches
1.6.1.2 Theme Keyword: EARTH SCIENCE > OCEANS > Coastal Processes > Erosion
1.6.1.2 Theme Keyword: EARTH SCIENCE > OCEANS > Coastal Processes > Estuaries
1.6.1.2 Theme Keyword: EARTH SCIENCE > OCEANS > Coastal Processes > Shoreline Displacement
1.6.1.2 Theme Keyword: EARTH SCIENCE > OCEANS > Coastal Processes > Shorelines
1.6.1.1 Theme Keyword Thesaurus: None
1.6.1.2 Theme Keyword: vector
1.6.1.2 Theme Keyword: county
1.6.1.2 Theme Keyword: 7.5-minute quadrangle
1.6.1.2 Theme Keyword 3.75-minute quadrangle
1.6.2 Place
1.6.2.1 Place Keyword Thesaurus: U.S. Geological Survey, Index to Topographic and Other Map Coverage: Maryland, Delaware, and District of Columbia (38076-H4-MI-99X), 22 p.
1.6.2.2 Place Keyword: Maryland (MD)
1.6.2.2 Place Keyword: Chesapeake Bay
1.6.2.2 Place Keyword: Delaware (DE)
1.6.2.2 Place Keyword: District of Columbia (DC)
1.6.2.2 Place Keyword: Virginia (VA)
1.6.2.2 Place Keyword: See Appendix 1 – County, and Appendix 2 - Quadrangle

1.7 Access Constraints: None

1.8 Use Constraints: The DOQQs from which the shorelines were interpreted meet National Map Accuracy Standards at the production scale of 1:12,000 using the American Society for Photogrammetry and Remote Sensing (ASPRS) method. Consider the scale in displaying and using the vectors. Displaying the vectors at scales larger than those of the source documents is considered bad practice.
See Section 2.4.1.1 Horizontal Positional Accuracy Report for positional inaccuracies in the data set.
The aerial photography from which the DOQQs were developed was not tide-coordinated. Therefore, shorelines in this data set do not represent a consistent vertical datum.

1.9 Point of Contact
10 Contact Information
10.1 Contact Person Primary
10.1.1 Contact Person: Lamere Hennessee
10.1.2 Contact Organization: Maryland Geological Survey
10.4 Contact Address
10.4.1 Address Type: mailing and physical address
10.4.2 Address: 2300 St. Paul Street
10.4.3 City: Baltimore
10.4.4 State or Province: Maryland
10.4.5 Postal Code: 21218-5210
10.4.6 Country: USA
10.5 Contact Voice Telephone: (410) 554-5519
10.7 Contact Facsimile Telephone: (410) 554-5502
10.8 Contact Electronic Mail Address: lhennessee@dnr.state.md.us
10.9 Hours of Service: 9:00 a.m. - 5:00 p.m. EST

1.11 Data Set Credit: Partial funding for this data set was provided by the National Oceanic and Atmospheric Administration (NOAA) and made available through the Maryland Coastal Zone Management Program of the Department of Natural Resources (CZM). In particular, shorelines were extracted or photo interpreted under NOAA Award No. NA87OZ0236, CZM Grant M00-050 CZM 031; erosion rate attributes were assigned under NOAA Award No. NA17OZ1124, CZM Grant 14-03-891 CZM 046. The views expressed herein are those of the authors and do not necessarily reflect the views of NOAA or any of its sub-agencies.

1.13 Native Data Set Environment:

- Software: ArcGIS 8.2
- Operating system: Microsoft Windows 2000
- File size: Less than 4 Mb per county; for exact sizes, see Appendix 3 - File size.
- File format: ESRI Arc coverage

1.14 Cross Reference
8 Citation Information
8.1 Originator: Maryland Geological Survey
8.2 Publication Date: 2003
8.4 Title: Determining Shoreline Erosion Rates for the Coastal Regions of Maryland (Part 2)
8.6 Geospatial Data Presentation Form: vector digital data
8.8 Publication Information
8.8.1 Publication Place: Baltimore, Maryland, USA
8.8.2 Publisher: Maryland Geological Survey
8.9 Other Citation Details: CD-ROM SLChangeRatesAll
1.14 Cross Reference
8 Citation Information
8.1 Originator: Maryland Geological Survey
8.2 Publication Date: 2000
8.4 Title: Historical Shorelines, 1841-1976: Chesapeake Bay Region of Maryland
8.6 Geospatial Data Presentation Form: vector digital data
8.8 Publication Information
8.8.1 Publication Place: Baltimore, Maryland, USA
8.8.2 Publisher: Maryland Geological Survey
8.9 Other Citation Details: CD-ROM SCSL_RVC
1.14 Cross Reference
8 Citation Information
8.1 Originator: Maryland Geological Survey
8.2 Publication Date: 2001
8.4 Title: Shoreline Changes maps
8.6 Geospatial Data Presentation Form: map
8.8 Publication Information
8.8.1 Publication Place: Baltimore, Maryland, USA
8.8.2 Publisher: Maryland Geological Survey

### 2 Data Quality Information

2.1 Attribute Accuracy: Accuracy of the shoreline type attributes was not assessed.
CGIS checked the accuracy of the erosion rate classification by displaying both the shore-normal transects and the shoreline, color-coded, respectively, by erosion rate (ft/yr) and erosion rate category (high, moderate, low, etc.). If the color of the transects matched the color of the associated shoreline segment, CGIS accepted the erosion rate classification. Otherwise, CGIS changed the classification.
2.2 Logical Consistency Report: EDI checked logical consistency through a series of quality assurance/quality control (QA/QC) procedures, reported in Section 2.5.2 Process Step (interpretation/extraction of shorelines).
2.3 Completeness Report: The area covered includes 125 7.5-minute quadrangles lying at least partially within Baltimore City or one of the 16 coastal counties of Maryland. (Appendix 2 lists the quadrangles for which shoreline rates-of-change were calculated. Appendix 3 lists the constituent quadrangles of each county.) Shorelines located in out-of-state areas, such as the Virginia side of the Potomac River, were excluded.
In digitizing historical shorelines from hard copy maps, MGS had adopted an operational definition of the headward extent of a stream - the point at which the stream was represented on the map by a single line rather than a double line delineating opposite stream banks. That point, dependent as it is on the scale of the map, does not necessarily represent the head of tide. A similar criterion was used in extracting the 1990 shoreline. To the extent that the contractor could fit a double line on photography displayed at a scale of 1:24,000, the shoreline was extracted. Reaches upstream of that point were excluded. Again, the headward extent of a digitized stream does not necessarily correspond with head of tide.

Shorelines in the 1990 data set bounded several different wetlands classifications (Cowardin et al., 1979):

1. E 1 UB L (Estuarine -- Subtidal -- Unconsolidated bottom -- Subtidal)
2. E 2 US M (Estuarine – Intertidal – Unconsolidated shore – Irregularly exposed)
3. E 2 US N (Estuarine – Intertidal – Unconsolidated shore – Regularly flooded)
4. E 2 US P (Estuarine – Intertidal – Unconsolidated shore – Irregularly flooded)
5. M 2 US M (Marine – Intertidal – Unconsolidated shore – Irregularly exposed)
6. M 2 US N (Marine – Intertidal – Unconsolidated shore – Regularly flooded)
7. R 1 UB V (Riverine -- Tidal -- Unconsolidated bottom -- Permanent tidal (tidally influenced, freshwater system)
8. R 2 UB 8 – (Riverine -- Lower perennial -- Unconsolidated bottom -- Eusaline)

In addition to designating UB L and UB V as water, M 2 or E 2 US (Unconsolidated shore) M (Irregularly flooded) or N (Regularly flooded) classifications were considered water, given that those areas were more likely to be under water than above. E 2 US P (Irregularly flooded) was considered upland, given that those areas were more likely to be above water than under. In assigning rate-of-change attributes, MGS and CGIS devised and applied a number of rules, which are summarized below:

- Classify shoreline segments of the shoreline type “structure” as “protected.”
- When adding nodes to distinguish between shoreline reaches with different rates of change, insert nodes only after the occurrence of a series of four or more similarly colored transects. For example, along an extensive reach that has experienced moderate rates of erosion, interrupted by two adjacent transects characterized by high erosion rates, classify the entire stretch of shoreline as “moderate.” If, instead of two high-rate transects, six high-rate transects occur in a row, insert nodes on either side of the six transects, and classify that shoreline reach as “high.”
- If shorelines are so complex that it is difficult to distinguish between the two shoreline years or to see that they are properly positioned, assign the erosion rate category “Unknown.” This problem is particularly common in marshy areas and/or along minor tributaries of dubious positional accuracy. A common manifestation of the latter is that one bank of the tributary is erosional along its entire length, while the opposite bank is accretional.
- For reaches lacking transects, estimate rates based on the relative positions of the two shorelines. This situation is common along points of land projecting into the water.
- Classify stretches represented by a single shoreline as “No Data.”
- If the two shorelines interweave over an extended reach, with little lateral displacement, classify the stretch as “No Change.”

2.4 Positional Accuracy
2.4.1 Horizontal Positional Accuracy
2.4.1.1 Horizontal Positional Accuracy Report: The DOQQs meet National Map Accuracy Standards at the production scale of 1:12,000, using the American Society for Photogrammetry and Remote Sensing (ASPRS) method. The contractor who produced the DOQQs provided a detailed aerotriangulation report for each production area (See DOQQ metadata at the web site listed in Section 2.5 Lineage).
The production of accurately georeferenced DOQQs depends on sufficient ground control. In open water, ground control is necessarily lacking, because land areas, if they exist at all, are small and/or inaccessible. Two quarter quads in the data set, Deal Island NW and Barren Island NE, contain so much open water that they are not properly tied to the adjoining tiles, Nanticoke SW and Honga NW, respectively. Consequently, the corresponding linework (shoreline) is not properly georeferenced. The shorelines derived from those two DOQQs are included in the data set solely for the associated attribute (shoreline type) information. Their positions are inaccurate.

2.5 Lineage
2.5.1 Source Information
2.5.1.1 Source Citation
8 Citation Information
8.1 Originator: Maryland Department of Natural Resources, Chesapeake and Coastal Watershed Service, Geographic Information Services Division
8.2 Publication Date: 1988-1995
8.4 Title: Digital Orthophoto Quarter Quads (DOQQs)
8.6 Geospatial Data Presentation Form: raster digital data
8.8 Publication Information
8.8.1 Publication Place: Annapolis, Maryland, USA
8.8.2 Publisher: Maryland Department of Natural Resources, Chesapeake and Coastal Watershed Service, Geographic Information Services Division
8.9 Other Citation Details: For complete metadata for this source, see the following web site: http://www.msgic.state.md.us/techtool/samples
2.5.1.2 Source Scale Denominator: 12000
2.5.1.3 Type of Source Media: CD-ROM
2.5.1.4 Source Time Period of Content
9 Time Period Information
9.2 Multiple Dates/Times – See Appendix 2 – Date of photography
9.3 Range of Dates/Times
9.3.1 Beginning Date: 19880417
9.3.3 Ending Date: 19950325
2.5.1.4.1 Source Currentness Reference: date on which aerial photography was flown
2.5.1.5 Source Citation Abbreviation: Digital Orthophoto Quarter Quads (DOQQs)
2.5.1.6 Source Contribution: Photo interpretation of the DOQQs resulted in the Maryland DNR Wetlands Inventory, from which most of the recent shorelines were extracted. In areas where a wetlands coverage was not yet available, EDI interpreted shorelines directly from the orthophotography.
2.5.1.1 Source Citation
8 Citation Information
8.1 Originator: Maryland Department of Natural Resources, Chesapeake and Coastal Watershed Service, Geographic Information Services Division
8.2 Publication Date: 1988-1995
8.4 Title: Maryland DNR Wetlands Inventory}
8.6 Geospatial Data Presentation Form: vector digital data
8.8 Publication Information
8.8.1 Publication Place: Annapolis, Maryland, USA
8.8.2 Publisher: Maryland Department of Natural Resources, Chesapeake and Coastal Watershed Service, Geographic Information Services Division
8.9 Other Citation Details: For complete metadata for this source, see the following website: http://www.msgic.state.md.us/techtool/samples
2.5.1.2 Source Scale Denominator: 12000
2.5.1.3 Type of Source Media: CD-ROM
2.5.1.4 Source Time Period of Content
9 Time Period Information
9.2 Multiple Dates/Times – See Appendix 2 – Date of photography
9.3 Range of Dates/Times
9.3.1 Beginning Date: 19880417
9.3.3 Ending Date: 19950325
2.5.1.4.1 Currentness Reference: ground condition on date of photography
2.5.1.5 Source Citation Abbreviation: MD DNR wetlands
2.5.1.6 Source Contribution: Most of the recent shorelines were extracted from the DNR wetlands inventory, a vector data set interpreted from DOQQs.
2.5.1.1 Source Citation
8 Citation Information
8.1 Originator: Maryland Department of Natural Resources, Chesapeake Bay & Watershed Programs, Resource Assessment Service, Maryland Geological Survey (MGS)
8.2 Publication Date: 2003
8.4 Title: Determining Shoreline Erosion Rates for the Coastal Regions of Maryland (Part 2)
8.6 Geospatial Data Presentation Form: vector digital data
8.8 Publication Information
8.8.1 Publication Place: Baltimore, Maryland, USA
8.8.2 Publisher: Maryland Department of Natural Resources, Chesapeake Bay & Watershed Programs, Resource Assessment Service, Maryland Geological Survey (MGS)
8.9 Other Citation Details: CD-ROM SLChangeRatesAll 2003
2.5.1.3 Type of Source Media: CD-ROM
2.5.1.4 Source Time Period of Content
9 Time Period Information
9.1 Single Date/Time
9.1.1 Calendar Date: 2003
2.5.1.4.1 Source Currentness Reference: publication date
2.5.1.5 Source Citation Abbreviation: Transect-based rates of shoreline change
2.5.1.6 Source Contribution: The attribute table associated with almost 250,000 shore-normal transects, constructed at 20-meter intervals along shore, includes linear rates of shoreline change for the ~50-year era ending ca. 1990. Negative rates indicate shoreline retreat, and positive rates, shoreline advance.
2.5.2 Process Step (interpretation/extraction of shorelines; assignment of shoreline type attributes)
2.5.2.1 Process Description: Under contract to MGS, EDI extracted or interpreted the modern (1988-1995) shoreline directly or indirectly from digital orthophotography. For all but 35 of the quarter quads, EDI extracted the shoreline from existing wetlands vectors, previously delineated for the Maryland Department of Natural Resources (DNR) over 1:1,000-scale DOQQs. The DOQQs, in turn, were derived from 1:40,000-scale color infrared (CIR) film. For the remaining 35 quarter quads, the shoreline was interpreted directly from the DOQQs.
For shoreline vectors extracted from the existing wetlands coverage, EDI stripped wetlands vectors of their linear attributes (line classes). All shorelines and the DOQQ tile boundary were displayed over the DOQQ (raster) from which they were originally interpreted and reassigned attributes. Shoreline segments were classified using the following four categories: beach, structure, vegetated, and water’s edge. All four categories are linear features, except for "beach," which can be both linear and polygonal. The DOQQ tile boundary was arbitrarily assigned one of the four categories so that it could be extracted with the shoreline vectors. Shoreline vectors were extracted from the original vector set by line class, using only the four shoreline categories. The extracted vectors were then displayed to detect shoreline breaks or other inconsistencies. Errors were corrected, and shoreline vectors were re-extracted. After extraction, vector sets were cleaned by deleting any extraneous lines (non-shoreline vectors) that had mistakenly been assigned one of the four categories before extraction. Beach polygons were attributed at this time, and the DOQQ tile boundary was assigned to a fifth category -unclassified. The final quality control check consisted of two steps. First, each tile (quarter quad) was displayed individually to check for unclassified shoreline vectors. Second, if the photography on which the DOQQs were based was flown in the same year, vectors from adjacent tiles were merged into a single, 7.5-minute quadrangle vector set. Otherwise, multi-year shorelines for the same quadrangle were stored as separate objects within the TNTmips project (.rvc) file. Merged vector sets were displayed to check for class consistency (proper edge matching) between adjacent tiles. Any necessary corrections were made before saving the final vector sets.
Shorelines derived directly from DOQQs were interpreted according to the procedure outlined in the wetlands inventory metadata.
The DOQQs were already georeferenced to the Maryland State Plane Coordinate System (North American Datum of 1983, meters). Georeferencing was transferred automatically upon delineating either wetlands or shorelines.
MGS subsequently converted beach polygons to line segments by removing the landward edge of the polygon.
2.5.2.2 Source Used Citation Abbreviation: MD DNR Wetlands
2.5.2.3 Process Date:
9 Time Period Information
9.3 Range of Dates/Times
9.3.1 Beginning Date: 1995
9.3.3 Ending Date: 2000
2.5.2.6 Process Contact (interpretation/extraction of shorelines; assignment of shoreline type attributes)
10 Contact Information
10.2 Contact Organization Primary
10.2.1 Contact Organization: EarthData International of Maryland
10.2.1 Contact Person: Michelle Hutchinson
10.4 Contact Address
10.4.1 Address Type: mailing and physical address
10.4.2 Address: 7320 Executive Way
10.4.3 City: Frederick
10.4.4 State or Province: Maryland
10.4.5 Postal Code: 21704
10.4.6 Country: USA
10.5 Contact Voice Telephone: (301) 948-8550
10.7 Contact Facsimile Telephone: (301) 963-2064
10.8 Contact Electronic Mail Address: http://www.earthdata.com
10.9 Hours of Service: 9:00 a.m. -5:00 p.m. EST
2.5.2 Process Step (assignment of rate-of-change categories)
2.5.2.1 Process Description: In collaboration with MGS, Towson University’s Center for Geographic Information Sciences (CGIS) assigned generalized rate-of-change categories to recent shoreline vectors, using transect-based erosion rates generated by a U.S. Geological Survey (USGS) computer program, the Digital Shoreline Analysis System (DSAS). DSAS constructs a 50-meter buffer around a series of digital shorelines. From the landward side of the buffer, or baseline, DSAS casts transects at 20-meter intervals, perpendicular to the baseline. For each transect, DSAS computes rates of change based on all shorelines intersected by the transect, as well as rates for each successive pair of shorelines. If, for example, a transect crosses shorelines from 1850, 1900, 1950, and 1990, DSAS output includes rates for the following “eras”: 1850-1900, 1900-1950, and 1950-1990. In assigning erosion rate attributes to the ca. 1990 shoreline, MGS and CGIS used rates based on the most recent era, that is, the one ending in 1988-1995. Usually, that era spanned approximately 50 years, from the 1940s to the 1990s. In some cases, however, the era was considerably shorter (e.g., 1975-1990) or longer (e.g., 1850-1990).
CGIS assigned erosion rate attributes to the recent shoreline by:

1. Color-coding transects according to previously established rate-of-change categories:

- High – High erosion rate (more than 8 ft/yr)
- Moderate – Moderate erosion rate (4-8 ft/yr)
- Low – Low erosion rate (2-4 ft/yr)
- Slight – Slight erosion rate (0-2 ft/yr)
- Accretion

2. Visually grouping similarly colored transects,
3. Inserting nodes between transects that differed in color, and
4. Assigning the appropriate classification code to the shoreline reach.

The rules that CGIS followed in the process are described in 2.3 Completeness Report.
2.5.2.2 Source Used Citation Abbreviation: Transect-based rates of shoreline change
2.5.2.3 Process Date:
9 Time Period Information
9.3 Range of Dates/Times
9.3.1 Beginning Date: 200304
9.3.3 Ending Date: 200306
2.5.2.6 Process Contact (assignment of rate-of-change categories)
10 Contact Information
10.1 Contact Person Primary
10.1.1 Contact Person: Mary J. Valentino and Ashley M. Lesh
10.1.2 Contact Organization: Center for Geographic Information Sciences
10.4 Contact Address
10.4.1 Address Type: mailing and physical address
10.4.2 Address: Towson University
10.4.2 Address: 8000 York Road
10.4.3 City: Towson
10.4.4 State or Province: Maryland
10.4.5 Postal Code: 21252-0001
10.4.6 Country: USA
10.5 Contact Voice Telephone: (410) 704-3887
10.7 Contact Facsimile Telephone: (410) 704-3888
10.9 Hours of Service: 9:00 a.m. -5:00 p.m. EST
2.6 Cloud Cover: 0 (for DOQQs)

3 Spatial Data Organization Information
3.2 Direct Spatial Reference Method: Vector

4 Spatial Reference Information
4.1 Horizontal Coordinate System Definition
4.1.2 Planar
4.1.2.1 Map Projection
4.1.2.1.1 Map Projection Name: Lambert Conformal Conic
4.1.2.1.2 Map Projection Parameters for Lambert Conformal Conic
4.1.2.1.2.1 Standard Parallel: 38.3
4.1.2.1.2.1 Standard Parallel: 39.45
4.1.2.1.2.2 Longitude of Central Meridian: -77.0
4.1.2.1.2.3 Latitude of Projection Origin: 37.67
4.1.2.1.2.4 False Easting: 400,000
4.1.2.1.2.5 False Northing: 0
4.1.2.2 Grid Coordinate System
4.1.2.2.1 Grid Coordinate System Name: State Plane Coordinate System 1983
4.1.2.2.4 State Plane Coordinate System (SPCS)
4.1.2.2.4.1 SPCS Zone Identifier: 1900 (Maryland)
4.1.2.4 Planar Coordinate Information
4.1.2.4.1 Planar Coordinate Encoding Method: coordinate pair
4.1.2.4.4 Planar Distance Units: meters
4.1.4 Geodetic Model
4.1.4.1 Horizontal Datum Name: North American Datum of 1983
4.1.4.2 Ellipsoid Name: Geodetic Reference System 80
4.1.4.3 Semi-major Axis: 6,378,137 meters
4.1.4.4 Denominator of Flattening Ratio: 298.257
4.2 Vertical Coordinate System Definition
4.2.2 Depth System Definition
4.2.2.1 Depth Datum Name: The aerial photography from which the DOQQs were developed was not tide-coordinated. Therefore, shorelines in this data set do not represent a consistent vertical datum.

5 Entity and Attribute Information
5.1 Detailed Description
5.1.1 Entity Type
5.1.1.1 Entity Type Label: Shoreline
5.1.1.2 Entity Type Definition: The shoreline, based on photo interpretation, is the dividing line between land and sea. The DOQQs, the ultimate source of the shorelines, were not based on tide-coordinated photography. Therefore, the shoreline vectors do not represent a consistent vertical datum.
5.1.1.3 Entity Type Definition Source: Operational definition agreed upon by MGS and EDI
5.1.2 Attribute
5.1.2.1 Attribute Label: TYPE_
5.1.2.2 Attribute Definition: Shoreline type, based on photo interpretation
5.1.2.3 Attribute Definition Source: Classification agreed upon by MGS and EDI
5.1.2.4 Attribute Domain Values
5.1.2.4.1 Enumerated Domain
5.1.2.4.1.1 Enumerated Domain Value: beach
5.1.2.4.1.2 Enumerated Domain Value Definition: Any sandy beach-like area, not including mud flats. All beaches on this CD-ROM are linear features. Originally, very narrow beaches were represented as linear features; wider beaches were represented as both lines and polygons. For this exercise, the landward edge of beach polygons was erased, leaving a line that represents the land/water boundary.
5.1.2.4.1.3 Enumerated Domain Value Definition Source: Photo interpretation convention
5.1.2.4.1.1 Enumerated Domain Value: structure
5.1.2.4.1.2 Enumerated Domain Value Definition: Any type of manmade object that serves as the land/water boundary. Structures include, but are not limited to, bulkheads, seawalls, and riprap.
5.1.2.4.1.3 Enumerated Domain Value Definition Source: Photo interpretation convention
5.1.2.4.1.1 Enumerated Domain Value: vegetated
5.1.2.4.1.2 Enumerated Domain Value Definition: Any portion of shoreline with vegetation, such as marsh, forest, or cropland, as the dominant land cover.
5.1.2.4.1.3 Enumerated Domain Value Definition Source: Photo interpretation convention
5.1.2.4.1.1 Enumerated Domain Value: waters edge
5.1.2.4.1.2 Enumerated Domain Value Definition: Any reach of shoreline that does not qualify as beach, structure, or vegetated. This may include mud flats.
5.1.2.4.1.3 Enumerated Domain Value Definition Source: Photo interpretation convention
5.1.2.4.1.1 Enumerated Domain Value: unclassified
5.1.2.4.1.2 Enumerated Domain Value Definition: Used to identify the DOQQ tile boundary line. Also used to identify the large polygon(s) enclosed by the DOQQ tile boundary line.
5.1.2.4.1.3 Enumerated Domain Value Definition Source: Classification agreed upon by MGS and EDI
5.1.2 Attribute
5.1.2.1 Attribute Label: LEVELID (erosion rate code) and associated EROSIONLEVEL (erosion rate)
5.1.2.2 Attribute Definition: Erosion rate code (LEVELID) and generalized erosion rate (EROSIONLEVEL), in feet per year, at which a reach of shoreline has advanced or retreated, based on the positions of the two most recent digital shorelines available for the reach. (The date of the later of these two shorelines is always between 1988-1995.)
5.1.2.3 Attribute Definition Source: Classification agreed upon by MGS and CGIS
5.1.2.4 Attribute Domain Values
5.1.2.4.1 Enumerated Domain
5.1.2.4.1.1 Enumerated Domain Value: LEVELID = 5; EROSIONLEVEL = High
5.1.2.4.1.2 Enumerated Domain Value Definition: Rate of shoreline retreat exceeding 8 ft/yr. 5.1.2.4.1.3 Enumerated Domain Value Definition Source: Classification agreed upon by MGS and CGIS
5.1.2.4 Attribute Domain Values
5.1.2.4.1 Enumerated Domain
5.1.2.4.1.1 Enumerated Domain Value: LEVELID = 4; EROSIONLEVEL = Moderate
5.1.2.4.1.2 Enumerated Domain Value Definition: Rate of shoreline retreat between 4-8 ft/yr.
5.1.2.4.1.3 Enumerated Domain Value Definition Source: Classification agreed upon by MGS and CGIS
5.1.2.4 Attribute Domain Values
5.1.2.4.1 Enumerated Domain
5.1.2.4.1.1 Enumerated Domain Value: LEVELID = 3; EROSIONLEVEL = Low
5.1.2.4.1.2 Enumerated Domain Value Definition: Rate of shoreline retreat between 2-4 ft/yr.
5.1.2.4.1.3 Enumerated Domain Value Definition Source: Classification agreed upon by MGS and CGIS
5.1.2.4 Attribute Domain Values
5.1.2.4.1 Enumerated Domain
5.1.2.4.1.1 Enumerated Domain Value: LEVELID = 2; EROSIONLEVEL = Slight
5.1.2.4.1.2 Enumerated Domain Value Definition: Rate of shoreline retreat between 0.01-2 ft/yr.
5.1.2.4.1.3 Enumerated Domain Value Definition Source: Classification agreed upon by MGS and CGIS
5.1.2.4 Attribute Domain Values
5.1.2.4.1 Enumerated Domain
5.1.2.4.1.1 Enumerated Domain Value: LEVELID = 0; EROSIONLEVEL = No Change
5.1.2.4.1.2 Enumerated Domain Value Definition: No change in shoreline position over time (-0.01 < EROSION(FT) < 0.01).
5.1.2.4.1.3 Enumerated Domain Value Definition Source: Classification agreed upon by MGS and CGIS
5.1.2.4 Attribute Domain Values
5.1.2.4.1 Enumerated Domain
5.1.2.4.1.1 Enumerated Domain Value: LEVELID = 1; EROSIONLEVEL = Accretion
5.1.2.4.1.2 Enumerated Domain Value Definition: Rate of shoreline advance exceeds 0.01 ft/yr.
5.1.2.4.1.3 Enumerated Domain Value Definition Source: Classification agreed upon by MGS and CGIS
5.1.2.4 Attribute Domain Values
5.1.2.4.1 Enumerated Domain
5.1.2.4.1.1 Enumerated Domain Value: LEVELID = 6; EROSIONLEVEL = Protected
5.1.2.4.1.2 Enumerated Domain Value Definition: Rate of shoreline advance or retreat not indicated, because shoreline reach is protected (i.e., shoreline type = structure).
5.1.2.4.1.3 Enumerated Domain Value Definition Source: Classification agreed upon by MGS and CGIS
5.1.2.4 Attribute Domain Values
5.1.2.4.1 Enumerated Domain
5.1.2.4.1.1 Enumerated Domain Value: LEVELID = 7; EROSIONLEVEL = Unknown
5.1.2.4.1.2 Enumerated Domain Value Definition: Rate of shoreline advance or retreat not indicated, usually because of obvious inaccuracies in relative positions of shorelines.
5.1.2.4.1.3 Enumerated Domain Value Definition Source: Classification agreed upon by MGS and CGIS
5.1.2.4 Attribute Domain Values
5.1.2.4.1 Enumerated Domain
5.1.2.4.1.1 Enumerated Domain Value: LEVELID = 8; EROSIONLEVEL = No Data
5.1.2.4.1.2 Enumerated Domain Value Definition: Rate of shoreline advance or retreat not indicated, because no historic shorelines are available for comparison.
5.1.2.4.1.3 Enumerated Domain Value Definition Source: Classification agreed upon by MGS and CGIS
5.1.2 Attribute
5.1.2.1 Attribute Label: DATE_
5.1.2.2 Attribute Definition: Date of photography, between 1988 and 1995, on which aerial photography was flown. In month/day /year (MM/DD/YYYY) format in attribute table; in year/month/day (YYYYMMDD) format in Appendix 2.
5.1.2.4 Attribute Domain Values
5.1.2.4.1 Enumerated Domain
5.1.2.4.1.1 Enumerated Domain Value: See Appendix 2 – Date of photography
5.1.2.4.1.3 Enumerated Domain Value Definition Source: Dates provided by DNR’s Geographic Information Services Division, which acquired the photography.
5.1.2 Attribute
5.1.2.1 Attribute Label: QUADRANGLE
5.1.2.2 Attribute Definition: USGS 7.5-minute quadrangle name
5.1.2.3 Attribute Definition Source: U.S. Geological Survey, Index to Topographic and Other Map Coverage: Maryland, Delaware, and District of Columbia (38076-H4-MI-99X), 22 p.
5.1.2.4 Attribute Domain Values
5.1.2.4.1 Enumerated Domain
5.1.2.4.1.1 Enumerated Domain Value: See Appendix 2 – Quadrangle
5.1.2.4.1.3 Enumerated Domain Value Definition Source: U.S. Geological Survey, Index to Topographic and Other Map Coverage: Maryland, Delaware, and District of Columbia (38076-H4-MI-99X), 22 p.
5.2 Overview Description
5.2.1 Entity and Attribute Overview
The 17 main directories on the CD-ROM, each assigned the full, concatenated name of a coastal county or Baltimore City, contain county or city shorelines, ca. 1990, assigned both shoreline type and shoreline rate-of-change attributes. The attribute tables associated with the coverages contain a field, LEVELID, linked to the rates table (ratestable). The rates table (Table 1), at the same level in the directory structure as the county and city directories, serves as a legend, which describes the LEVELID attributes of the coverage. For example, a shoreline segment assigned a LEVELID=3 has, in the recent past, retreated between 2-4 ft annually, which is considered a “low” rate of erosion. (Note: The rates table is only viewable in Arc, not in Windows.)

Table 1: Rates table (ratestable)

Rowid | LEVELID | EROSION (Ft/Yr) | EROSION LEVEL
4 | 0 | -0.01 to 0.01 | No Change
2 | 1 | >0.01 | Accretion
1 | 2 | -0.01 to –2.00 | Slight
5 | 3 | -2.00 to –4.00 | Low
6 | 4 | -4.00 to –8.00 | Moderate
8 | 5 | < -8.00 | High
3 | 6 | Protected Area | Protected
7 | 7 | Unknown | Unknown
9 | 8 | No Data | No Data

6 Distribution Information
6.1 Distributor
10 Contact Information
10.2 Contact Organization Primary
10.2.1 Contact Organization: Maryland Geological Survey
10.4 Contact Address
10.4.1 Address Type: mailing and physical address
10.4.2 Address: 2300 St. Paul Street
10.4.3 City: Baltimore
10.4.4 State or Province: Maryland
10.4.5 Postal Code: 21218-5210
10.4.6 Country: USA
10.5 Contact Voice Telephone: (410) 554-5500
10.7 Contact Facsimilie Telephone: (410) 554-5502
10.9 Hours of Service: 8:30 a.m. -4:30 p.m. EST
6.2 Resource Description: CD-ROM - CoErosionRates
6.3 Distribution Liability: None
6.4 Standard Order Process
6.4.1 Non-digital Form: Along with historical shoreline vectors, the recent shoreline vectors are being displayed over 1988-1995 orthophotoquads and printed as a paper map series, Shoreline Changes. A Shoreline Changes map is available for most of the quadrangles listed in Appendix 2. Each map is $7.50, plus postage and shipping. To order copies, contact the Publication Sales office at the Maryland Geological Survey (Telephone: (410) 554-5505).
6.4.2 Digital Form
6.4.2.1 Digital Transfer Information
6.4.2.1.1 Format Name: ESRI coverage
6.4.2.1.2 Format Version Number: ESRI ArcGIS version 8.1 or later
6.4.2.1.6 File Decompression Technique: No compression applied
6.4.2.1.7 Transfer Size: Less than 4 Mb/county; see Appendix 3 - File size.
6.4.2.2 Digital Transfer Option
6.4.2.2.2 Offline Option
6.4.2.2.2.1 Offline Media: CD-ROM
6.4.3 Fees: Contact the Maryland Geological Survey (Section 6.1) for current fees.

7 Metadata Reference Information
7.1 Metadata Date: 20030714
7.4 Metadata Contact
10 Contact Information
10.1 Contact Person Primary
10.1.1 Contact Person: Lamere Hennessee
10.1.2 Contact Organization: Maryland Geological Survey
10.4 Contact Address
10.4.1 Address Type: mailing and physical address
10.4.2 Address: 2300 St. Paul Street
10.4.3 City: Baltimore
10.4.4 State or Province: Maryland
10.4.5 Postal Code: 21218-5210
10.4.6 Country: USA
10.5 Contact Voice Telephone: (410) 554-5519
10.7 Contact Facsimile Telephone: (410) 554-5502
10.8 Contact Electronic Mail Address: lhennessee@dnr.state.md.us
10.9 Hours of Service: 9:00 a.m. -5:00 p.m. EST
7.5 Metadata Standard Name: FGDC Content Standards for Digital Geospatial Metadata
7.6 Metadata Standard Version: FGDC-STD-001-1998 (June 1998)

### APPENDIX 1

### Bounding Coordinates of Maryland’s Coastal Counties and Baltimore City

County (Sec. 1.6.2.2) | Bounding coordinates (Sec. 1.5.1)
West ° | East ° | North ° | South °
Anne Arundel | - 76.8413 | -76.3486 | 39.2358 | 38.7169
Baltimore City | -76.7122 | -76.5294 | 39.3719 | 39.1977
Baltimore County | -76.8977 | -76.2663 | 39.7350 | 39.1544
Calvert | -76.7041 | -76.3605 | 38.7675 | 38.3058
Caroline | -76.0163 | -75.6983 | 39.1438 | 38.6483
Cecil | -76.2380 | -75.7522 | 39.7244 | 39.3597
Charles | -77.3422 | -76.6619 | 38.7063 | 38.1755
Dorchester | -76.4430 | -75.6997 | 38.7022 | 38.0113
Harford | -76.5730 | -76.0288 | 39.7322 | 39.2594
Kent | -76.3522 | -75.7544 | 39.3880 | 38.9925
Prince Georges | -77.0905 | -76.6691 | 39.1311 | 38.5327
Queen Annes | -76.4238 | -75.7261 | 39.2683 | 38.7872
Somerset | -76.1894 | -75.5216 | 38.3119 | 37.8838
St. Marys | -76.8883 | -76.1852 | 38.5108 | 37.8713
Talbot | -76.4627 | -75.8908 | 38.9491 | 38.5736
Wicomico | -75.9569 | -75.3077 | 38.5716 | 38.2008
Worcester | -75.6633 | -75.0450 | 38.4555 | 37.9938

###
APPENDIX 2

### Shoreline Dates, by Quadrangle

Quadrangle | Quadrants | Date of photography YYYYMMDD
Aberdeen | SE | 19940408
Alexandria | NE, SE | 19930407
Annapolis | NE, NW, SW | 19940408
Assawoman Bay | NE, NW, SE, SW | 19890412
Baltimore East | SE | 19940408
SW | 19940404
Baltimore West | SE | 19940404
Barren Island1 | NE2 | 19940408
SW | 19930408?
Benedict | NE, NW, SE, SW | 19930408
Berlin | NE, SE, SW | 19890412
Betterton | NE, NW, SE, SW | 19950325
Blackwater River | NE, NW, SE, SW | 19950325
Bloodsworth Island | NE, NW, SE, SW | 19880417
Boxiron | NE, NW, SE, SW | 19890412
Bristol | NE, SE | 19940404
NW, SW | 19930408
Broomes Island | NE, NW, SE, SW | 19930408
Cambridge | NE, NW, SE, SW | 19950325
Cecilton | NE, NW, SE, SW | 19950325
Centreville | NE, NW, SE, SW | 19920406
Charlotte Hall | SW | 19930408
Chestertown | NE, NW, SE, SW | 19920406
Chicamacomico River | NE, NW, SE, SW | 19950325
Church Creek | NE, NW, SE, SW | 19940408
Church Hill | NE, NW, SW | 19920406
Claiborne | NE, NW | 19920406
SE, SW | 19940408
Colonial Beach North | NE, NW, SE | 19930408
Cove Point | NW, SE, SW | 19930408
Crisfield | NE, NW, SW | 19880417
Curtis Bay | NE, SE | 19940408
NW, SW | 19940404
Deal Island2 | NE, NW, SE, SW | 19880417
Deale | NE, SE | 19940408
SW | 19940404
Denton | NE, NW, SW | 19950325
Dividing Creek | SE | 19890414
Earleville | NE, NW, SE, SW | 19950325
East New Market | NW, SE, SW | 19950325
Easton | NW, SE, SW | 19950325
Eden | NE | 19890417
NW, SW | 19880417
Edgewood | NE, SE, SW | 19940408
Elkton | NW, SE, SW | 19950325
Ewell | NE | 19880417
Federalsburg | NE, SE, SW | 19950325
Fowling Creek | NE, NW, SE, SW | 19950325
Galena | NE, NW, SW | 19950325
SE | 19920406
Gibson Island | NE, NW, SE, SW | 19940408
Girdletree | NW | 19880330
NE, SE | 19890412
Golden Hill | NE, NW, SE, SW | 19940408
Great Fox Island | NE, NW, SE | 19880417
Gunpowder Neck | NE, NW, SE, SW | 19940408
Hallwood | NW | 19890414
Hanesville | NE, NW, SE, SW | 19940408
Havre de Grace | NE, NW, SE, SW | 19950325
Hebron | NW | 19890417
Hobbs | NW, SW | 19950325
Hollywood | NE, NW, SW | 19930408
Honga | NE, NW, SE, SW | 19940408
Horseshoe Point | NW | 19940408
Hudson | NE, NW, SE, SW | 19940408
Indian Head | NE, NW, SE, SW | 19930407
Kedges Straits | NE, SE | 19880417
NW | 19890414
Kent Island | NE, NW, SE, SW | 19920406
King George | NE, NW | 19930407
Kingston | NW, SW | 19880417
SE | 19890417
Langford Creek | NE, NW, SE, SW | 19920406
Leonardtown | NW, SE, SW | 19930408
Love Point | SE, SW | 19920406
Lower Marlboro | NE, NW, SE, SW | 19930408
Mardela Springs | NE, NW, SE, SW | 19880417
Marion | NE, NW, SE, SW | 19880417
Mathias Point | NE, NW, SE, SW | 19930407
Mechanicsville | NE, NW, SE | 19930408
Middle River | NE, NW, SE, SW | 19940408
Millington | NW | 19950325
SW | 19920406
Monie | NE, NW, SE, SW | 19880417
Mount Vernon | NE, NW, SW | 19930407
Nanjemoy | NE, SE, SW | 19930407
Nanticoke | NE, SE | 19880417
NW, SW | 19950325
North Beach | NE, NW, SE, SW | 19930408
North East | NE, NW, SE, SW | 19950325
Ocean City | NW, SW | 19890412
Oxford | NE, NW, SE, SW | 19940408
Perryman | NE, NW, SE, SW | 19940408
Piney Point | NE, NW, SE | 19930408
Pocomoke City | NE, NW, SW | 19890414
Point Lookout | NW, SW | 19930408
Point No Point | NW, SW | 19930408
Popes Creek | SE, SW | 19930408
Port Tobacco | NW, SE | 19930407
Preston | NE, NW, SE, SW | 19950325
Prince Frederick | NE, NW, SE | 19930408
Princess Anne | NW, SW | 19880417
SE | 19890417
Public Landing | NE, NW, SE | 19890412
Quantico | SE | 19930407
Queenstown | NE, NW, SE, SW | 19920406
Rhodesdale | NE, NW | 19950325
SE, SW | 19880417
Richland Point | NE | 19940408
Ridgely | SW | 19920406
Rock Hall | NE, NW, SE, SW | 19940408
Rock Point | NE, NW, SE, SW | 19930408
Round Bay | NE, SE | 19940408
NW, SW | 19940404
Salisbury | NW | 19890414
Saxis | NE | 19890417
NW | 19880417
Selbyville | NE, NW, SE, SW | 19890412
Sharptown | SW | 19890417
Snow Hill | NE, SE | 19890417
SW | 19880330
Solomons Island | NE, NW, SE, SW | 19930408
South River | NE, SE | 19940408
NW, SW | 19940404
Sparrows Point | NE, NW, SE, SW | 19940408
Spesutie | NE, NW, SE, SW | 19950325
St. Clements Island | NE, NW | 19930408
St. George Island | NE, NW | 19930408
St. Marys City | NE, NW, SE, SW | 19930408
St. Michaels | NE, NW | 19920406
SE, SW | 19940408
Stratford Hall | NE | 19930408
Sudlersville | NW | 19920406
Swan Point | NE, NW, SE | 19940408
Taylors Island | NE, NW, SE | 19940408
Terrapin Sand Point | NE, SE | 19880417
NW, SW | 19890420
Tilghman | NE, NW, SE, SW | 19940408
Tingles Island | NE, NW, SE, SW | 19890412
Trappe | NE, NW, SE, SW | 19950325
Wetipquin | NE, NW, SE, SW | 19880417
White Marsh | SE | 19940408
Whittington Point | NE, NW, SW | 19890412
Widewater | NE, SE | 19930407
Wingate | NE, NW, SE, SW | 19950325
Wye Mills | NW, SE, SW | 19920406

1 The date of photography for Barren Island SW is unknown. Although Barren Island NE was flown on 4/8/1994, Solomons Island SE, which adjoins Barren Island SW, was flown on 4/8/1993. The latter date was assigned to Barren Island SW.

2 The production of accurately georeferenced DOQQs depends on sufficient ground control. In open water, ground control is necessarily lacking, because land areas, if they exist at all, are small and/or inaccessible. Two quarter quads in the data set, Deal Island NW and Barren Island NE, contain so much open water that they are not properly tied to the adjoining tiles, Nanticoke SW and Honga NW, respectively. Consequently, the corresponding linework (shoreline) is not properly georeferenced. The shorelines derived from those two DOQQs are included in the data set solely for the associated shoreline type attributes. Their positions are inaccurate.

### APPENDIX 3

### Constituent Quadrangles and Attributed Shoreline File Size, by County

### County | 7.5’ Quadrangles | File size
Anne Arundel | Annapolis, Bristol, Curtis Bay, Deale, Gibson Island, Horseshoe Point, North Beach, Round Bay, South River, Sparrows Point | 1.32 MB
Baltimore City | Baltimore East, Baltimore West, Curtis Bay | 140 KB
Baltimore County | Baltimore East, Curtis Bay, Edgewood, Gunpowder Neck, Middle River, Sparrows Point, Swan Point | 578 KB
Calvert | Benedict, Bristol, Broomes Island, Cove Point, Lower Marlboro, Mechanicsville, North Beach, Prince Frederick, Solomons Island | 812 KB
Caroline | Preston, Trappe | 260 KB
Cecil | Earleville, Elkton, Galena, Havre de Grace, Millington, Northeast, Spesutie | 334 KB
Charles | Benedict, Charlotte Hall, Colonial Beach North, Indian Head, King George, Mathias Point, Mechanicsville, Mount Vernon, Nanjemoy, Popes Creek, Port Tobacco, Quantico, Rock Point, Widewater | 776 KB
Dorchester | Barren Island, Bloodsworth Island, Cambridge, Church Creek, Cove Point, Deal Island, East New Market, Golden Hill, Honga, Hudson, Kedges Straits, Nanticoke, Oxford, Point No Point, Preston, Richland Point, Taylors Island, Tilghman, Wetipquin, Wingate | 3.19 MB
Harford | Aberdeen, Edgewood, Gunpowder Neck, Hanesville, Havre de Grace, Perryman, Spesutie | 710 KB
Kent | Betterton, Chestertown, Galena, Hanesville, Langford Creek, Millington, Rock Hall, Swan Point | 760 KB
Prince Georges | Alexandria, Benedict, Bristol, Lower Marlboro, Mount Vernon | 428 KB
Queen Annes | Chestertown, Claiborne, Galena, Kent Island, Langford Creek, Love Point, Millington, Queenstown, Ridgely, St. Michaels | 1.13 MB
Somerset | Bloodsworth Island, Crisfield, Deal Island, Ewell, Great Fox Island, Kedges Straits, Kingston, Marion, Monie, Saxis, Terrapin Sand Point, Wetipquin | 3.72 MB
St. Marys | Barren Island, Benedict, Broomes Island, Charlotte Hall, Hollywood, Leonardtown, Mechanicsville, Piney Point, Point Lookout, Point No Point, Rock Point, Solomons Island, St. Clements Island, St. George Island, St. Marys City, Stratford Hall | 2.80 MB
Talbot | Cambridge, Claiborne, St. Michaels, Tilghman | 2.08 MB
Wicomico | Deal Island, Monie, Nanticoke, Wetipquin | 1.03 MB
Worcester | Assawoman Bay, Berlin, Boxiron, Girdletree, Ocean City, Public Landing, Selbyville, Tingles Island, Whittington Point | 1.62 MB

updated 9/4/03