Sustainable Urban Development Major
Environmental StudiesMinor
GIS Certificate and Restoration Ecology Certificate
LiDAR data for 3D Modeling
LiDAR - Light Detection and Ranging
"LiDAR is a remote sensing procedure that uses laser pulses to determine the distance between a LiDAR unit and another object or surface." (Lund) This data is usually collected by air and is a fairly large datasets, which requires enormous processing power to analyze.
To determine the height of the buildings on the University of Washington Tacoma's campus, LiDAR data, that was collected during an aerial overflights of Pierce County, had to be analyzed.
How do you analyze the LiDAR data? Well, there are 2 datasets. The first return, (ALL) is associated with the highest feature on the landscape. The last return is associated with the bare earth (BE).
Before being able to determine the height of the building, two rasters of eleveation will be created from the ALL and BE LiDAR datasets. From the text data in the table, two new points will be made, (X/Y). (Figure 1 and 2) In order to turn the LiDAR points to a Raster, interpolation must be done. It is suggested to use the IDW tool to convert the data from a feature into a floating -point raster. (Figure 3)
Before analyzing the data to determine height, the buildings layer needs to be converted from polygons to points though. (Figure 4) Then their heights can be calculated. There are two types of ArcMap tools/methods that could be used: Zonal Statistics or Extract Values to Points. However, Zonal Statistics is a more accurate height because it calculated mean height. To determine the height, the bare earth (BE) is subtracted from the absolute height of the building (ALL). (Figure 5)
UWT Campus
ArcMap
Creating Raster Elevations
Figure 2.
Figure 1.
Figure 2.
BE Returns
ALL Returns
ALL Returns
Figure 3.
ArcScene 3D
From 2D to 3D
In Arc Scene, the 2-D layer created in Arc Map is made into a 3-D image. (Figure 5)
Figure 5.
Final Poster of UWT Campus Building Heights
