RiverCOG

Contours are lines of equal elevation. This is a contour feature layer for the state of Connecticut derived from the index contour in the 1' contour data set. All closed polygons less than 35' length have been deleted to improve loading performance. This data set is derived from the 2023 Lidar with15 to 20 points per meter squared.

Source:
1 foot contours were generated for each production block from the final bare earth DEMs using ArcGIS software. Contours are labeled as intermediate or index with index contours set to every 10th interval. Using ArcGIS software, the contours were validated for correct topology, including must not intersect, must not self intersect, and must not have dangles. Contours are then manually reviewed with the 3D breaklines to ensure complete coverage, correct coding, data integrity and that contours behave correctly around water bodies, water crossings, and elevated features such as overpasses. The contours are then clipped to individual tiles as creating one dataset for the entire project renders the feature class un-usable. Enclosed contours completely within building footprints were removed from the final contour dataset.

Coordinate System:

The data was developed based on a horizontal datum/projection of NAD83 (2011), State Plane Connecticut, U.S. Survey Feet and vertical datum of NAVD88 (GEOID18)

Contours were cut by Town then merged into COGs

Geographic Extent

• Coverage: State of Connecticut

Classifications

• Sensitivity: Public
• Usage: Public Use
• Quality: High Quality
• Known Quality Issues: None known, but subject to standard limitations of third-party commercial data
  Organization: State of Connecticut
  Last updated: 2025-11-29T22:12:04.243046
  Tags: 1-foot-contours, 2023, connecticut, ct-gis-office, elevation-data