Evaluation of lidar data for engineering design

Topographic information is needed for the design of several conservation structures such as grassed waterway and subsurface drainage. There are various ways to obtain the topographic information such as GPS and total station surveys. Another option may be to utilize Light Detection and Ranging (LiDAR) data, which covers larger swaths of land and requires significantly less labor to acquire. This paper explores the differences in the elevation and slope data of LiDAR data and total station data in a flat farm in Champaign County, Illinois. The accuracy of each point was evaluated using root mean square error (RMSE), mean absolute error (MAE), and mean biased error (MBE). The elevation points of the raw data from each source were converted into contours using Kriging. The contours were compared at 0.5 ft contour intervals to determine if there were any visual trends in the differences in the data. To check for relative errors versus absolute errors in elevation, the elevation values in the LiDAR dataset were lowered by the average error. Contours were made once again to analyze these differences visually.