Name: Rates of Change Transects

Display Field: DecadeCalc

Type: Feature Layer

Geometry Type: esriGeometryPolyline

Description: To quantify rates of change (erosion or accretion) along coastal and estuarine shorelines in Maryland, the Maryland Geological Survey (MGS), and the U.S. Geological Survey (USGS), installed and ran a computer program, the Digital Shoreline Analysis System (DSAS), using as input a series of digital shoreline vectors dating from 1841-1995. Shorelines were derived from three sources: (1) maps from a Historical Shorelines and Erosion Rates Atlas (Conkwright, 1975), (2) Coastal Survey maps (topographic or T-sheets) produced by the National Ocean Service (NOS), a branch of the National Oceanic and Atmospheric Administration (NOAA), and (3) a digital wetlands delineation based on photo interpretation of digital orthophoto quarter quads. DSAS constructed a “baseline” landward of and approximately parallel to the shorelines, inserted nodes every 20 m along the baseline, and cast straight-line transects from each node, perpendicular to the baseline, across the shorelines. Based on the time elapsed and the along-transect distance between shoreline pairs, DSAS calculated rates of change for each transect. Subsequently, updates began in 2015 is updating by county the DSAS process using newer Shoreline data and refined calculations to update the Rates of Change erosion values by county. Currently Anne Arundel, Baltimore, Calvert, Harford and Prince George's counties have the newest erosion rate values contained in this Data set.

Copyright Text: MD iMAP, DNR

Default Visibility: true

MaxRecordCount: 65000

Supported Query Formats: JSON, geoJSON

Min Scale: 0

Max Scale: 0

Supports Advanced Queries: true

Supports Statistics: true

Has Labels: false

Can Modify Layer: true

Can Scale Symbols: false

Use Standardized Queries: true

Supports Datum Transformation: true

Extent:

XMin: -8602155.7169
YMin: 4567316.633000001
XMax: -8354397.8947
YMax: 4810537.590599999
Spatial Reference: 102100  (3857)

Drawing Info:

Renderer:
Simple Renderer:
Symbol:
Style: esriSLSSolid
Color: [104, 104, 104, 255]
Width: 2
Label:
Description:
Transparency: 0
Labeling Info:

Advanced Query Capabilities:

Supports Statistics: true
Supports OrderBy: true
Supports Distinct: true
Supports Pagination: true
Supports TrueCurve: true
Supports Returning Query Extent: true
Supports Query With Distance: true
Supports Sql Expression: true
Supports Query With ResultType: false
Supports Returning Geometry Centroid: false

HasZ: false

HasM: false

Has Attachments: false

HTML Popup Type: esriServerHTMLPopupTypeAsHTMLText

Type ID Field: null

Fields:

• OBJECTID ( type: esriFieldTypeOID, alias: GIS Object ID )
• RecentRate ( type: esriFieldTypeDouble, alias: Recent Rate )
• DecadeCalc ( type: esriFieldTypeString, alias: Decade Calculation, length: 50 )
• Erosion_Level ( type: esriFieldTypeString, alias: Erosion Level, length: 50 )
• County ( type: esriFieldTypeString, alias: County, length: 50 )
• Process_Date ( type: esriFieldTypeDate, alias: Process Date, length: 8 )
• FIRST_TIME ( type: esriFieldTypeString, alias: First Time DSAS, length: 15 )
• BaseLineCalc ( type: esriFieldTypeString, alias: Baseline Calculation, length: 50 )
• Shape ( type: esriFieldTypeGeometry, alias: GIS Shape )
• Shape.STLength() ( type: esriFieldTypeDouble, alias: Shape.STLength() )

Supported Operations:   Query   Generate Renderer   Return Updates

  Iteminfo   Thumbnail   Metadata