Connecticut Terrain Dataset, version 1 is a digital terrain model of the state of Connecticut in ESRI terrain dataset format. The primary elevation point data source for the terrain is the Connecticut 2000 LiDAR Masspoints. The USGS Topographic Map Masspoints provide additional elevation data in areas of data gaps in the Connecticut 2000 LiDAR Masspoints. The terrain also makes use of two boundary feature classes to clip the terrain to the Connecticut state boundary at different scale thresholds. This dataset is labeled "version 1" because as new LiDAR data becomes available, new statewide terrain datasets will be created.
Connecticut Terrain Dataset, version 1 has a wide range of uses including visual display and querying of elevation, slope, aspect, and contours; generation of raster digital elevation models (DEMs) and contour lines; and use as an input for analysis tasks such as creating viewsheds, calculating surface area and volume, and interpolating z-values to other data layers.
These data are not consistently accurate statewide. Users should review the following description of source data in order to determine appropriate uses of this information. The primary point data source is 20-foot posting lidar data collected in 2000, which has a horizontal positional accuracy of approximately 3 feet on the ground. The lidar point data has known limitations including data gaps. The secondary point data source that contributes to the terrain dataset was compiled by Center for Land Use Education and Research (CLEAR) at the University of Connecticut, College of Agriculture and Natural Resources. It is a collection of points intended to fill in gaps in the lidar data with coarser data based on contour lines from USGS topographic maps. Before building the terrain dataset, this secondary point data source was further edited by DEP to remove unnecessary points that occurred in areas of dense lidar point data.
79 Elm Street
The primary data source for the terrain, the Connecticut 2000 LiDAR Masspoints, was a part of the 2004 Statewide Aerial Survey of Connecticut, provided by Aero-Metric, Inc. of Sheboygan, Wisconsin on a contract with the State of Connecticut. TerraPoint LLC of Woodlands, Texas, was subcontracted to create a Connecticut Statewide LiDAR dataset.
The Connecticut 2000 LiDAR Masspoints are the main elevation data source for the terrain dataset. The data is 20-foot posting covering the state of Connecticut, and has a horizontal positional accuracy of approximately 3 feet on the ground. However, the data has known limitations, including data gaps.
These point data were used to fill in some of the gaps that are a known limitation of the Connecticut 2000 LiDAR Masspoints. This data were derived from contour lines appearing on USGS 1:24,000-scale Digital Raster Graphics (DRGs) by the Center for Land Use Education and Research (CLEAR). The data were further edited by CT DEP to remove points that occurred in areas of dense LiDAR coverage.
This boundary layer is used to clip the terrain dataset to the state boundary when the terrain is displayed at large scales (specifically, at a maximum scale of 1:25,000).
This boundary layer is used to clip the terrain dataset to the state boundary when the terrain is displayed at small scales (specifically, at a minimum scale of 1:25,001).
79 Elm Street