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Elevation | LiDAR

A coordinated effort with the federal USGS 3D Elevation Program (3DEP) Program

Download LiDAR (compressed .las files) or Download DEMs (Digital Elevation Models)

Business Plan | LiDAR FAQ | Inventory Map | Resources

In December 2017, The Department of Finance and Administration, STS-GIS Services was awarded $731,122 from the USGS to support another 3DEP project.  Starting in February 2018, lidar data for 18 counties in middle TN will be collected to support geospatial data development in Tennessee.  In addition to the USGS funding, other partners for this project include:  the Tennessee Department of Transportation,  the Tennessee Valley Authority, Department of Agriculture and F&A, STS-GIS Services along with Rutherford and Williamson counties.  With this acquisition, the four year plan to acquire lidar for all of Tennessee will be complete.

*Note:  the map below depicts the counties in TN that were collected through the USGS 3DEP program only.  Lidar data for a portion of west TN and other counties scattered across the State were collected through other programs.

The following sections provide detailed information about the project's Business Plan/Tech Specs, a LiDAR FAQ sheet, a LiDAR Inventory Map, Business Plan Events and a LiDAR Resources page.

Business Plan

The first step to accomplish our mission on this project is to create a business plan that identifies the business requirements, costs, and benefits of creating a LiDAR derived elevation GIS dataset. In addition, documenting the appropriate technical specifications, and related processes to the LiDAR data, is a foundational element associated with this project.

Using grant funding from FGDC and the NSGIC "50 States Initiative", STS - GIS Services and Applied Geographics conducted regional GIS coordination meetings and stakeholder interviews to gather detailed business requirements that support the argument of why Tennessee should invest in LiDAR/elevation GIS data products.

Here are the results from these coordination/outreach efforts:

LiDAR FAQ

1. What is LiDAR?

LiDAR is an optical remote sensing technology that measures properties of scattered light to find range and/or other information of a distant target. This technology is used to measure distance and derive highly accurate elevation data.

2. Does Tennessee have existing elevation data?

Yes. Through the original Tennessee Base Mapping Program (2000-2007), STS - GIS Services developed digital terrain models (DTM) primarily for ortho rectification.

3. Why does Tennessee need LiDAR "enhanced" elevation data?

While very useful, the original DTM data doesn't meet the vertical accuracy requirements for all digital elevation needs in the State.

4. What are the differences between the original DTM data and the LiDAR derived "enhanced" elevation data?

The original photogrammetric derived standard DTM data has a vertical accuracy of +/- seven feet; suitable for a 10 foot contour that meets ASPRS class 2 standards. LiDAR derived "enhanced" elevation data can achieve a vertical accuracy of up to +/- 9cm, suitable for a 1 or 2 foot contour that meets ASPRS class 1 standards.

For more FAQ's regarding LiDAR in general, please see the following document developed by USGS as part of a national assessment for enhanced elevation:

Inventory Map

Inventory Map

Click image to view a larger version.

Project Summary Details:

Resources

LiDAR, or Light Detection and Ranging, is an evolving technology used to support a wide variety of geospatial business needs at all levels of government and in the private sector.

Instead of defining our own interpretation or understanding of LiDAR, we are providing the following URL's that best describe the technology, resources, associated elevation data products, and how to apply the technology for specific applications.

Contacts

Dennis Pedersen

Director of STS GIS Services
615-741-9356
dennis.pedersen@tn.gov

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