LIDAR stands for LIght Detection and Ranging. It uses the same principle as RADAR except that it uses a laser instead of radio waves. One of the principle uses for LiDAR is for the measurement of elevation. For a more complete explanation of LiDAR, visit the NASA's LiDAR tutorial page at http://www.ghcc.msfc.nasa.gov/sparcle/sparcle_tutorial.html.

When will the entire state be covered?

The file format of the LIDAR will depend on the form of representation of elevation data. In its raw form, LiDAR is a series of points stored as x, y, z where x and y can be longitude and latitude; z is the elevation in meters or feet. A simple ASCII file where each line has a coordinate (x,y,z) separated by commas (tabs, spaces, etc.) can be used to represent the data.

Another representation for LIiDAR data is as contours lines. The lines can be stored in a number of different CAD and GIS file formats.

A third representation for LIDAR data is as a digital elevation model (DEM). This is a raster format with a matrix (grid) with rows and columns. Each cell is of a fixed sized relative to the earth's surface; each cell holds the average elevation calculated from LIDAR points for that area of the earth's surface represented by the cell.

There are additional ways to represent LIDAR data such as triangular irregular networks (TIN) and profiles.

Currently, Atlas has LIDAR data in four different forms: contours, digital elevation models, edited points, and raw points. The contour data is in shapefile format. The digital elevation models are in the USGS DEM format. The point data - both raw and edited - are in ASCII csv (comma separated value) files.

Any program that can read a USGS DEM file. Bentley Inroads, ERDAS Imagine, ESRI ArcInfo, ESRI ArcView (with the 3D Analyst extension), KeiganSystems MFWorks, and Intergraph MGE Terrain Analyst are a few of the programs that can read USGS DEM files.

CAD programs such as AutoDesk AutoCAD and Bentley MicroStation can not read DEM files directly, but there are extensions (or companion products) that allow a CAD user to use DEM files with these CAD programs. Examples are Bentley's Inroads and Intergraph MTA. Most Civil Engineering applications read USGS DEMs.