University of Washington, Tacoma:
Campus Buildings in 3D
Figure 2
Figure 3
The purpose of this project was to create a three-dimensional representation of the buildings of the University of Washington, Tacoma campus.
Introduction
Figure 1
LiDAR data layers, including 'All Returns' and 'Bare Earth', were turned into point features using the ‘Display XY Data’ tool. The points in each layer were interpolated into a raster surface using an inverse distance weighted (IDW) technique. These results appear in Figure 1 and Figure 2 for 'All Returns' and 'Bare Earth', respectively.
To determine the heights of the buildings on the UWT campus, ground elevation was subtracted from the building elevation. This was accomplished using two methods for comparison purposes. In the first method, ‘Zonal Statistics’ was used to create data tables containing a complete set of statistics based on the values of each raster grid within each of the building footprints. To calculate building height, the mean height of the bare earth data was subtracted from all returns data for each building footprint.
In the second method, ‘Extract Values to Points’ the cell values in the building footprints of each raster were extracted to the corresponding building points. Once again, building heights were derived from calculating the difference between bare earth elevation and the absolute height of the buildings.
Campus maps were consulted to ensure the integrity of the building footprint data, and a ground-truthing procedure was conducted to ensure the integrity of the derived building heights. Four missing buildings were drawn into the footprint data, and two buildings were split by dividing the polygons, as shown in Figure 3. Estimated building heights were assigned to these new polygons.
ArcScene was used to extrude the building heights and produce a three-dimensional model of the UWT campus buildings. The results of each building height analysis method were compared. The ‘Zonal Statistics’ method appeared more accurate to the true building heights and the extrusion was applied to each feature’s maximum height, since the buildings are on sloping ground. The results of this process appear in Figure 4. The buildings are symbolized by contrasting colors.
Method
Results
Figure 4