LiDAR (Light Detection and Ranging) is a surveying method that measures distance to a target by illuminating that target with a pulsed laser light, and measuring the reflected pulses with a sensor. Differences in laser return times and wavelengths can then be used to make digital 3D-representations of the target. (Source: Wikipedia)
Since 2001, NCTCOG's RIS Department has coordinated the purchase of LiDAR for interested entities. Until recently, elevation data was only collected approximately every 5-7 years. Now with technological advancements in how LiDAR can be used and the data becoming more affordable, entities are purchasing it more frequently and using it to create derivative projects like topographic contours, impervious surface analysis, change detection and 3D planimetrics.
NCTCOG has contracted with a vendor to acquire 2 different types of LiDAR, when needed.
0.5 Meter LiDAR
LiDAR is collected at a density sufficient to support a nominal pulse spacing of 0.5 meters or less (i.e., with no less than 4 or more points per square meter). NCTCOG LiDAR, which includes hydrologic breaklines, is delivered in a LAS-formatted file based scheme set using the ASPRS LAS format 1.2 specifications and includes the following classifications.
|Class 2||Bare earth|
|Class 3||Low vegetation|
|Class 4||Medium vegetation|
|Class 5||High vegetation|
|Class 7||All noise|
|Class 17||Overlap default/unclassified|
|Class 18||Overlap ground|
0.5 meter LiDAR projects may be viewed and printed from DFWMaps and purchased in digital format through the DFWMaps Marketplace.
Sample LiDAR File (LAS format)
For more information on LiDAR, visit the SDCP FAQ page or send us an email.
Past LiDAR Projects