LiDAR – Case Studies

Project Name: Albany County Storm Water Mapping Project
Period of Performance: 2010
Budget: ~$50K
Customer: Storm Water Coalition of Albany County

CS-LiDAR1This project was conducted by GroundPoint Technologies as part of a larger project to create high resolution elevation and hydrography data and host it in a web based application supporting storm water infrastructure mapping for a coalition of MS4 regulated municipalities led by Albany County. The Project Area was approximately 523 square miles and involved processing classified LiDAR point cloud data into various derived GIS data such as elevation models, 2-ft Contours, Void Areas and Steep Slopes.

In order for most regulated MS4s to use a LiDAR based DEM for drainage analysis and catchment level mapping, the elevation surface models must be “hydro-conditioned”. This includes “hydro-flattening” as described in the current USGS standards for large water bodies, and “hydro-enforcement” which integrates the drainage network into the elevation model. Hydro-conditioning goes further to support additional post-processing of the entire terrain surface that results in an “artificial DEM” that becomes the basis for accurate flow direction and flow accumulation modeling used in hydrologic analysis. This is an essential pre-requisite for assessing mapped storm water outfalls and their contributing catchments.

This effort involved compiling hydrographic updates (streams) and, and hydro-conditioning the digital elevation data for surface flow modeling to account for artifacts and errors inherent in the laser scan data. Final deliverables included both topographic (i.e., for contour mapping) and hydrologically enforced (i.e., for hydrologic analysis) Digital Elevation Models (DEMs), as well as derived flow direction and flow accumulation raster data to support drainage catchment mapping.

 

 

Project Name: LiDAR Data Processing
Period of Performance: 2009-2014
Budget: ~$5-$50K
Customer: Various

CS-LiDAR2GroundPoint staff has been processing LiDAR data into derived products for over 10 years. Typical derived products include:

  • reclassified point clouds (ground, water, trees),
  • 3-D breaklines for terrain mapping,
  • Bare earth digital elevation models (DEM),
  • first return digital surface models (DSM),
  • contours (2ft, 1ft),
  • analysis of void areas,
  • gridded slope, and
  • intensity data.

In the past three years we have performed over 25 data processing projects across the continental United States. In addition, we have performed more than a dozen formal Quality Control and Accuracy Assessments based on current ASPRS, FEMA and USGS standards.
GroundPoint staff have also coordinated and contracted for the acquisition of airborne LiDAR data on behalf clients. Example Projects include:

NY Capital District- Brokered a ~$400K LiDAR collection covering almost 800 square miles for the counties of Schenectady and Albany.

NYS Combined Collection Brokered a ~$1.2M LiDAR collection covering over 2000 square miles, supported by three separate funding agencies. The collection effort included subcontracts with two different collection vendors, two survey subcontracts, and a contract for Quality Control and Accuracy Assessment. The collection covered five locations around NYS including all of Chemung and Cortland Counties, and portions of Onondaga, Ulster, and Herkimer Counties. The ability to broker the collection resulted in a coordinated effort that reduced the overall cost per square mile for each of the funding participants.