Elevation Contours


In cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. 

Over the years, NCTCOG has been partnering with remote sensing consultants to create contours for varying parts of the 16 county region.  In 2020, NCTCOG created a new, highly-accurate "multi-year" contour layer by aggregating NCTCOG LiDAR data from 2015-2019 where available and TNRIS LiDAR data.  The resulting dataset covers the majority of the 16-county region and is available for purchase on the DFW Marketplace.  More information on the multi-year contour layer can be found here.  

For future contour projects, NCTCOG’s chosen consultant will utilize 0.5 meter LiDAR data to create 1-foot or 2-foot contours for any defined project area.  Breaklines and  can be added to better depict edge of drainage feature, road edges and other sharp breaks or discontinuities in the terrain.  Data will meet or exceed NMAS vertical accuracies for 2-foot (1.0’ RMSE).  If requested, consultant will apply smoothing to create a more traditional looking contour dataset.  If desired, entity can choose to have 1-foot contours created.  However, 0.5 meter LiDAR is not considered dense enough to consistently produce accurate 1-foot contours, so consultant will need to use surface data from 3-inch imagery to bolster the LiDAR data if 0.5” RMSE is required. 

Contour data is available in GIS (shapefile) and CAD (DWG) format and will contain an elevation attribute that will hold the photogrammetrically obtained elevation.

The scope of any Contour project is dependent upon the needs of that year’s participating entities. Contour data from previous project years  may be viewed, printed, and purchased in digital format after a project completes through the DFW Marketplace.  

Sample Contour File


Past SDCP Contour Projects

2015-2020 Digital Elevation Contours
2007 Digital Elevation Contours
2001 Digital Elevation Contours

 

For more information about contours, send us an email.