LiDAR

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.
 
The RIS Department is now offering two types of LiDAR. 

 

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 1 Default/unclassified
Class 2 Bare earth
Class 3 Low vegetation
Class 4 Medium vegetation
Class 5 High vegetation
Class 6 Building
Class 7 All noise
Class 9 Water
Class 17 Overlap default/unclassifed
Class 18 Overlap ground

 

 

Single Photon LiDAR

 

For large project areas (1000 sq. miles or more), NCTCOG is now offering Single Photon LiDAR, which captures data at the lowest cost per data point using 100 outlet beams.   The Leica/Hexagon SPL allows you to create the highest density point clouds by collecting 12-30 points per square meter.  The scope of any LiDAR project is dependent upon the needs of that year’s participating entities.   

0.5 meter LiDAR from the 2015 & 2017 projects may be viewed and printed from DFWMaps and purchased in digital format through the DFWMaps Marketplace

For more information on LiDAR, visit the SDCP FAQ page or contact Shelley Broyles (GIS Project Coordinator).

 

 

Past LiDAR Projects

 

2017 LiDAR
2015 LiDAR
2007 Autocorrelated Surface
2001 LiDAR