Elevation Image Services
The elevation, hillshade, shaded relief, aspect, and slope image services on CT ECO are now using 2023 elevation. Previously, they were displaying 2016 elevation. The 2023 (and 2016) services can all be found on the Map and Image Services page under Elevation.
Elevation Viewer
The Elevation Viewer now contains 2023 and 2016 elevation layers including slope, aspect, hillshade, and shaded relief. It also contains reference layers such as parcels, watersheds, and aerial imagery.
New Services
New base elevation 2023 and 2016 services are published. The include Statewide 2023 and Statewide2016 in Web Mercator projection (WKID 3857) and Statewide 2023 CTspNAD83 2011 and Statwide2016_CTspNAD83_2011 in, you guessed it, CT State Plane NAD 83 2011 (WKID 6434) projection. services include processing templates to easily display the elevation as aspect, hillshade, shaded relief, and slope.
2016 Services and Processing Templates
The individual aspect, hillshade, shaded relief, and slope services for 2016 are no longer available but they are not lost! The base Statewide 2016 service and Statewide 2016 CTspNAD83 2011 service are available and include processing templates for aspect, hillshade, shaded relief, and slope. Processing templates are pre-defined strings of raster functions packaged and delivered with the elevation image services. When applied, they change the way the service looks and not the underlying data. Learn more on the Raster Processing Templates: Accessing and Applying for Elevation page.
Download
Both the 2023 and 2016 bare earth elevation DEM tiles are available in the download tool on CT ECO. The lidar point clouds and contours are also downloadable, among other datasets.
Detail
DEM tiles are rasters meaning they are made of pixels. The value of each pixel is an average of the elevation of points that were captured within the pixel area on the ground. The 2016 lidar is Quality Level 2 (QL2) with a minimum of 2 points per square meter. The 2023 lidar is Quality Level 1 plus (QL1+) with a minimum of 15 points per square meter inland and 20 points per square meter along the coast.
Learn More
2023 Aerial Imagery and Elevation Info
How to add services to ArcGIS Pro
How to add services to ArcGIS Online
Raster Processing Templates: Accessing and Applying for Elevation
Under the Hood: Serving Lidar-Based DEMs