Connecticut Hydrography Polygon includes the polygon features of a layer named Hydrography. Hydrography is a 1:24,000-scale, polygon and line feature-based layer that includes all hydrography features depicted on the U.S. Geological Survey (USGS) 7.5 minute topographic quadrangle maps for the State of Connecticut. This layer only includes features located in Connecticut. These hydrography features include waterbodies, inundation areas, marshes, dams, aqueducts, canals, ditches, shorelines, tidal flats, shoals, rocks, channels, and islands. Hydrography is comprised of polygon and line features. Polygon features represent areas of water for rivers, streams, brooks, reservoirs, lakes, ponds, bays, coves, and harbors. Polygon features also depict inundation areas, marshes, dams, aqueducts, canals, tidal flats, shoals, rocks, channels, and islands shown on the USGS 7.5 minute topographic quadrangle maps. Line features represent single-line rivers and streams, aqueducts, canals, and ditches. Line features also enclose all polygon features in the form of natural shorelines, manmade shorelines, dams, closure lines separating adjacent waterbodies, and the apparent limits for tidal flats, rocks, and areas of marsh. The layer is based on information from USGS topographic quadrangle maps published between 1969 and 1984 so it does not depict conditions at any one particular point in time. Also, the layer does not reflect recent changes with the course of streams or location of shorelines impacted by natural events or changes in development since the time the USGS 7.5 minute topographic quadrangle maps were published. Attribute information is comprised of codes to identify hydrography features by type, cartographically represent (symbolize) hydrography features on a map, select waterbodies appropriate to display at different map scales, identify individual waterbodies on a map by name, and describe feature area and length. The names assigned to individual waterbodies are based on information published on the USGS 7.5 minute topographic quadrangle maps or other state and local maps. The layer does not include bathymetric, stream gradient, water flow, water quality, or biological habitat information. This layer was originally published in 1994. The 2005 edition includes the same water features published in 1994, however some attribute information has been slightly modified and made easier to use. Also, the 2005 edition corrects previously undetected attribute coding errors.

Connecticut Hydrography is 1:24,000-scale base map data. It depicts all of the hydrography information published on the USGS topographic quadrangle maps. For base map purposes, use this layer with other 1:24,000-scale base map data such as Roads and Trails, Railroads, Airports, and Towns. This layer may be used as a possible data source for other 1:24,000-scale layers with features that must coincide and line up with stream and shoreline features published on the USGS topographic quadrangle maps. For example, the layer includes a set of connecting line features referred to as Coastline Arcs, which define a shoreline between the Connecticut landmass and Long Island Sound. These Coastline Arc features are commonly used to close polygon features in other 1:24,000-scale layers published by the State of Connecticut, Department of Environmental Protection. For example, Coastline Arcs from the original Hydrography Master layer define the shoreline in the Waterbody, Named Waterbody, Towns, Basins, and Bedrock Geology layers. Note that related hydrography layers such as Waterbody, Waterbody Master, Named Waterbody, Named Waterbody Master, and Hydrography are all ultimately derived from the polygon and line features of the Hydrography Master layer. Typically, layers derived from Hydrography Master define a subset of polygon and line features for either the geographic area encompassed by all USGS topographic quadrangle maps that cover the State of Connecticut (a master layer) or the geographic area of the State of Connecticut, in which case the layer is clipped to the State boundary. The Hydrography layer is not intended for maps printed at map scales greater or more detailed than 1:24,000 scale (1 inch = 2,000 feet.)

In 2004, the State of Connecticut Department of Environmental Protection developed automated procedures to systematically maintain feature topology and attribute integrity for a set of related hydrography data maintained by the agency. These layers include Hydrography Master, Hydrography, Waterbody Master, Waterbody, Named Waterbody Master, and Named Waterbody. Automated procedures were developed using ArcInfo Workstation 8.3 software and the Arc Macro Language (AML) as a scripting environment and recorded in an AML file named MAKECOVER.AML for the hydrography category of data for the State of Connecticut, Department of Environmental Protection. The MAKECOVER.AML derives all related hydrography layers from one Hydrography Master layer. For additional information related to the original source of data from the U.S. Geological Survey, refer to the Data User Guides and Standards for 1:24,000-Scale Digital Line Graphs and Quadrangle Maps available from the U.S. Geological Survey, National Mapping Program.

The named waterbody information incorporated into the Hydrography, Waterbody and Named Waterbody layers was originally compiled and mapped by James Bogar, a Cartographer with the State of Connecticut, Department of Environmental Protection.

Publication dates of the USGS 7.5 minute topographic quadrangle maps for the State of Connecticut through 1984.

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 and the U.S. Geological Survey, National Mapping Program as the source for this information. For example, include the following data source description when printing this layer on a map: Hydrography - From the Hydrography layer, compiled and published by CT DEP and USGS. Source map scale is 1:24,000.

Includes linear and polygonal features for rivers, streams, brooks, reservoirs, lakes, ponds, bays, coves, harbors, marshes, dams, aqueducts, canals, drainage ditches, shorelines, tidal flats, submerged rocks, channels, and islands published on the U.S. Geological Survey 7.5 minute topographic quadrangle maps. Information encoded about features includes hydrography type classification, two standard symbology classification schemes, waterbody names, flags for named features, levels for mapping at different scales, feature area in acreage, and feature length in miles. Use the AV_LEGEND attribute to symbolize features by type. Use the IMS_LEGEND attribute to more generally symbolize the features by type. To define a layer that only includes named waterbodies, query line and polygon features for NAMEDP_COD and NAMEDA_COD values greater than 0. To define a layer that only includes named lakes, query the line and polygon features for LAKE_NO and LAKE_NO2 values greater than 0. To define a layer that only includes named streams, query the line and polygon features for STREAM_NO and STREAM_NO2 values greater than 0, and so on. To define a layer that only includes the Connecticut River, query line and polygon features for STREAM_NO and STREAM_NO2 equal to 374. The Stream number for the Connecticut River is 374. Each stream, lake, bay, and harbor can be queried by Id number. To define a layer that includes features typically displayed on a map, exclude all unnecessary features by querying the line and polygon features for AV_LEGEND not equal to "No Show" or IMS_LEGEND not equal to "No Show". Typically, line features with the "No Show" classification enclose Hydrography polygon features that are not outlined on a map. Examples of line features typically not shown on a map include closure lines separating adjacent open water polygons, boundaries defining bay and harbor extents, apparent limits of marsh polygons, apparent limits of rock polygons, apparent limits of tidal flat polygons, underground shorelines, and submerged streams. Define layers of hydrography for various map scale ranges by querying line and polygon features on SCALELEVEL values.

Hydrography represented as polygon features. Polygon features represent areas of water for rivers, streams, brooks, reservoirs, lakes, ponds, bays, coves, and harbors. Polygon features also depict inundation areas, marshes, dams, aqueducts, canals, tidal flats, shoals, rocks, channels, and islands shown on the USGS 7.5 minute topographic quadrangle maps.

State of Connecticut, Department of Environmental Protection and U.S. Geological Survey, National Mapping Program

Polygon features conform to the following topological rules. Polygons are single part. There are no duplicate polygons. Polygons do not self overlap. Polygons do not overlap other polygons. Polygons are bound by lines. Line features conform to the following topological rules. Lines are single part. There are no duplicate lines. Lines do not self overlap. Lines do not overlap other lines. Lines intersect only at nodes, and nodes anchor the ends of all lines. Lines do not overshoot or undershoot other lines they are supposed to meet and intersect. The tests of logical consistency were performed by the State of Connecticut using ESRI ArcInfo software to maintain feature topology in ArcInfo coverage format. The data is topologically clean. The ArcInfo Clean function was repeatedly used following edits to verify topology and enforce a minimum distance between vertices of 4 feet (fuzzy tolerance) and a minimum allowed overshoot length of 10 feet (dangle length).

The completeness of the data reflects the USGS National Mapping Division standards for feature content of the data sources, which are the Large Scale (7.5 minute) Digital Line Graph (DLG) files available from the USGS. For Connecticut, the Large Scale DLG files used to create this layer are for the 1:24,000-scale topographic quadrangle maps published between 1969 and 1984.  The layer is complete in the sense that it accurately reflects the contents of the most recently published USGS topographic quadrangle maps available at the time the State of Connecticut, Department of Environmental Protection began creating the layer. More recent quadrangle maps have been published by the USGS since 1984; however, the State of Connecticut did not incorporate this information into the layer. So compared to the most recent set of topographic quadrangle maps available today, the layer is incomplete, and substantially incomplete when compared to waterbodies present today. This data is not updated.