Internal feature number.

ESRI

ArcView Legend - A text field that differentiates existing and proposed sewer service areas. Use this field to symbololize the Sewer Service area polygon features on a map.

State of Connecticut, Department of Environmental Protection

Feature geometry.

ESRI

Includes various sewer system infrastructure maps maintained by municpal governments and sewer authorities that show the locations of sewer pipes, connections, mains, pumps, treatment facilities, etc. These maps are published at various map scales and publication dates.

unknown

Sewer Service Areas compiled by CT DEP on 1:24,000-scale 7.5 minute USGS quadrangle area Mylar overlays.

compilation date

This original version of the Connecticut Sewer Service Area data is in ArcInfo Coverage format with polygon feature topology. The name of the original coverage is SEWERSRV.

compilation date

The Connecticut Sewer Service Area in ArcInfo Coverage format was converted to ESRI Shapefile and then to GeoDatabase polygon feature format and named SEWER_SERVICE_AREA.

publication date

Create 1:24,000-scale Sewer Service Area Mylars - The original Sewer Service Area data in ArcInfo Coverage format was based on information mapped and subsequently digitized from a series of 1:24,000-scale Mylar overlays maintained by the State of Connecticut, Department of Environmental Protection (DEP). The following briefly describes a mapping effort to delineate service area boundaries statewide. Mylar overlays for each 1:24,000-scale, 7.5 minute topographic quadrangle map were made by placing a blank sheet of 2 millimeter Mylar on each topographic quadrangle map and manually drafting the neat lines (boundaries) of the topographic quadrangle map on the Mylar. The neat lines were drafted in India ink and are the basis for manually registering (lining up) the overlay to the corresponding topographic quadrangle map. At the time, these overlays were not prepared with the intent of creating a manuscript appropriate for digitizing. Rather, they were meant to be used with and the basis for manually delineating other 1:50,000 and 1:125,000 small-scale Mylar overlays for regional and statewide assessments of areas in Connecticut where sewer service is provided. Due to their 2-millimeter thickness, these Mylars are susceptible to expansion and contraction under varying humidity conditions. They are not a stable base. Also, the neat lines drawn on the overlays registered each overlay to the paper topographic quadrangle map and not a stable-base Mylar of the topographic quadrangle map. Stable-base Mylar is the preferred media when tablet digitizing.

Maps of individual sewer systems across Connecticut were obtained from municipalities and regional sewer authorities. These maps often included the locations of sewer pipes, connections, mains, pumps, treatment facilities, etc. They were published at various map scales and publication dates. CT DEP staff interpretted information on these maps and manually delineated sewer service boundaries on the corresponding quadrangle scale Mylar overlays. Service areas were delineated along streets and around structures and built-up areas shown on the USGS topographic quadrangle map where sewer pipes were present on the more detailed sewer system maps provided by the municipalities. The names of the sewer systems and locations of sewage treatment plants were also mapped on these Mylar overlays.

Create 1:24,000-scale Connecticut Sewer Service Area (initial coverage) - feature digitizing and attribution (digitizing tablet) method. Using ESRI ArcInfo software, sewer service polygon features were digitized by registering the source map to the digitizing tablet and using the crosshairs of the digitizer's mouse to manually capture the geometry (location) of features drafted on the map. The corners of the USGS 7.5 minute topographic quadrangle maps used as registration points and are depicted on the compilation sheets (Mylar overlays). Each compilation sheet was registered to the digitizing tablet by digitizing (entering) the locations of four quadrangle corner registration points shown on the map. ArcInfo software compared the values of the digitized coordinates with the actual (true) values for the quadrangle corner (tic) features. The Root Mean Square (RMS) error generated by the ArcInfo software indicated the amount of error involved in transforming coordinates from the registered map to the digital layer. RMS errors higher than 0.004 were not acceptable and required re-registering the source map by digitizing the tic locations again. With a correct registration, individual features were manually digitized off the source map and assigned values to distinguish (polygon) areas were sewer service is and is not provided. Where necessary, additional minor corrections (edits) to feature geometry were manually digitized on the screen (heads-up digitizing) at display scales greater than 1:24,000. Feature location and attribute accuracy was visually checked and inspected by symbolizing and labeling features according to attribute value on the computer screen and on hard copy paper maps, and comparing this information to the original information that were digitized. These check plot maps were printed at the same scale as the compilation sheets in order to visually inspect digitizing quality. The ends of service areas along quadrangle boundaries were drawn to line up with the corresponding sewer service boundaries on adjacent quadrangles. Sewer service boundary lines were first digitized as line features, creating an ArcInfo coverage for each USGS topographic quadrangle map area. Line features on adjacent quadrangle ArcInfo coverages were edgematched so that they would snap together and form enclosed polygon features when all quadrangle coverages were appended.  Using the ArcInfo Append command, the line feature based quadrangle coverages were appended to form a statewide coverage. Polygon feature topology was then created using the ArcInfo build command, and the resulting polygon features were manually attributed to identify sewer service polygon features verses those polgyon areas that are not sewered.

Update the 1:24,000-scale Connecticut Sewer Service Area - feature digitizing and attribution (heads up digitizing) method. Using ESRI ArcGIS software, features appearing on the more up to date sewer system maps from varous municipalities were manually digitized on the screen (heads-up digitizing) at display scales greater than 1:24,000 using either USGS 7.5 minute topographic quadrangle maps, orthophotography, or a street network displayed in the background for reference. In some instances, section of the street network were buffered to create new sewer service area polygon features. Sewer service area boundary and attribute accuracy was visually checked and inspected by symbolizing and labeling features according to attribute value on the computer screen and comparing this with information on the original sewer system map.

Starting in 1998, these procedures are followed to update the sewer service area information, as needed. Information is irregularly updated.

Minor update was made to New London and Waterford sewer service areas in May, 2006.