Connecticut Erosion Sites is a site specific, point feature-based layer developed at 1:24,000-scale that includes decriptive information regarding the character of the erosion (severity, slope, geologic factors) at selected locations through out the state. The layer is based on information collected and compiled during October-December, 2005 while field testing the applicability of the Erosion Susceptilibity layer developed as part of Project #03-02 Statewide GIS Analysis and Mapping of the Geologic Conditions Contributing to Eroding Terrace Escarpments. The layer represents conditions at a particular point in time. The layer includes 83 locations and descriptive attributes (site name, severity of erosion, description, etc) as well as attributes from a spatial join with merged soils and quaternary geology layers.  Features are point locations that represent the selected study areas within the state; it is NOT a comprehensive inventory of erosion locations.  Data is compiled at 1:24,000 scale. This data is not updated.

Connecticut Erosion Sites is a site specific data layer developed at 1:24,000-scale. The purpose of this layer is show locations and provide desriptions of erosion sites used to confirm the applicability of the draft erosion suscepibility map. Erosion sites were inventoried in selected areas of the state wide study area. This map should be used in conjunction with the final 1:24,000 scale Erosion Susceptibility layer and other documents developed for the Project #03-02: Statewide GIS Analysis and Mapping of the Geologic Conditions Contributing to Eroding Terrace Escarpments.  The objective of this project is to identify the geologic conditions that lead to eroding terrace escarpments throughout the state. This layer is part of an information package that can be used as a planning and management tools by state and municipal officials. Not intended for maps printed at map scales greater or more detailed than 1:24,000 scale (1 inch = 2,000 feet.)

For additional information, refer to Statewide GIS Analysis and Mapping of the Geologic Conditions Contributing to Eroding Terrace Escarpments, Project #03-02 Final Report, prepared by Mary L. DiGiacomo-Cohen, Long Island Sound Resource Center, University of Connecticut, Avery Point, Groton, CT 06340 in conjunction with North Central Conservation District, 24 Hyde Ave., Vernon, CT, 06066. Report prepared for Nonpoint Source Management Grant Program, Funded under Section 319 (h) of the Federal Clean Water Act, administered by the Connecticut Department of Environmental Protection.

publication date

None. The data is in the public domain and may be redistributed.

No restrictions or legal prerequisites for using the data. The data is suitable for use at appropriate scale, and is not intended for maps printed at scales greater or more detailed than 1:24,000 scale (1 inch = 2,000 feet). Although this data set  has been used by the State of Connecticut, Department of Environmental Protection, no warranty, expressed or implied, is made by the State of Connecticut, Department of Environmental Protection as to the accuracy of the data and or related materials.  The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the State of Connecticut, Department of Environmental Protection in the use of these data or related materials. The user assumes the entire risk related to the use of these data. Once the data is distributed to the user, modifications made to the data by the user should be noted in the metadata. When printing this data on a map or using it in a software application, analysis, or report, please acknowledge the State of Connecticut, Department of Environmental Protection as the source for this information. For example, include the following data source description when printing this layer on a map: Erosion_severity from the Erosion_sites layer, compiled and published by CT DEP. Source map scale is 1:24,000.

Includes Erosion sites features such as general descriptions, geologic and soils conditions at selected erosion locations. Information encoded about these features includes x and y coordinates and standard cartographic symbology classification schemes. Use the AV_LEGEND attribute to symbolize features by type on a map. Use the comment to label features on a map.  Additional related attribute data tables are not included with the distributed layer, but are available upon request. 

Erosion sites represented as point features.

State of Connecticut, Department of Environmental Protection

Point features conform to the following topological rules. Points are single part. There are no duplicate points. Points do not overlap. Establishment of logical consistency was performed by the State of Connecticut, Department of Environmental Protection using ESRI ArcGIS software to manually create and control feature topology in shapefile format. No automated procedures or tests were performed to guarantee desired topology other than visual inspection.

The completeness of the data reflects the feature content of the data sources, which include the FIELD DATA SHEETS for the project. The erosionsites layer is complete in the sense that it accurately reflects the contents of the Erosion sites field information available at the time the State of Connecticut, Department of Environmental Protection created the layer. However, compared to current conditions, the erosionsites layer is incomplete. This data is not updated.

The erosionsites layer retains the feature types and information identified by the State of Connecticut, Department of Environmental Protection and obtained from the data compiler. All attributes have valid values. Values are within defined domains. The accuracy test for the attribute values was conducted by comparing the information presented in the source data with 1:24,000-scale field sheets and interactive displays of the data on a computer graphic system. These check plot maps and computer displays depicted and labeled the erosionsites features in different colors based on values for comparison with the original data source.  AV_LEGEND and IMS_LEGEND are broad classifications of erosionsites features.  AV_LEGEND, and IMS_LEGEND were not manually entered. These additional fields were populated by calculating values equal to existing fields.  Erosionsites features were manually selected and populated with descriptive attributes values to (uniquely) identify and describe individual features. Attributes respresenting geologic and soils conditions for each sites, and erosion category were populated by spatial join. 

The horizontal positional accuracy of this data complies with the United States National Map Accuracy Standards for 1:24,000 scale maps. According to this standard, not more than 10 percent of the locations tested are to be in error by more than 1/50 inch (40 feet) measured on the publication scale of a USGS 7.5 minute topographic quadrangle map. Some feature locations were interpolated from the transporation features, surface water features, elevation contours, buildings, and built-up areas depicted on USGS 7.5 minute topographic quadrangle maps. Other feature locations were derived from GPS coordinates; their horizontal precision exceeds the map standard.Typically, the Trimble Pro XR collects data with the PDOP set to 6.0 and the S/N set to 10.0 the standard error of the collected data is less than 1 meter, so the 95% confidence is on the order of 2 meters.

Point features represent approximate positions for linear or large area objects or observations that are transient, variable or temporal in nature. 
 
Some features are accurately positioned because GPS-based coordinates were collected at the actual location of the site in the field, and other features are less accurately positioned because the site represents a large area which was interpolated from topographic quadrangle maps.

Connecticut Erosion Sites

Although this data set  has been used by the State of Connecticut, Department of Environmental Protection, no warranty, expressed or implied, is made by the State of Connecticut, Department of Environmental Protection as to the accuracy of the data and or related materials.  The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the State of Connecticut, Department of Environmental Protection in the use of these data or related materials. The user assumes the entire risk related to the use of these data. Once the data is distributed to the user, modifications made to the data by the user should be noted in the metadata.

Geographic information sytem (GIS), computer-aided drawing or other mapping software is necessary to display, view and access the information.

The data distributor does not provide custom GIS analysis or mapping services. Data is available in a standard format and may be converted to other formats, projections, coordinate systems, or selected for specific geographic regions by the party receiving the data.