Table 1. Lidar data is created using a laser, and made up of thousands of sample points. With the data can be broken out into multiple “layers” depending on what is needed. The bare earth return is data only from the ground. All return is data from everything such as trees, buildings, and also bare earth.
To start the analysis raw Lidar table data for bare earth and all returns were taken and converted into points. The points were then interpolated into a raster using inverse distance weighted (IDW) analysis (Figures 1 & 2).
The next step was to determine the heights of the buildings on the UW Tacoma campus. Two different methods were used to accomplish this, Zonal Statistics using the Zonal Statistics as Table tool and Extract Values to Points. Once this was accomplished ArcScene was then used to convert everything into 3D.
Fig 1. The all returns after running an inverse distance weighted (IDW) analysis.
Fig 2. The bare earth return after running an inverse distance weighted (IDW) analysis.
Fig 3. The buildings data was overlaid onto an aerial photo to see how well the buildings lined up.
Fig 4. Building off of the original building data, the campus was then field verified. Buildings that were not part of the original building data were added and all of the heights were checked in the field.
Fig. 5. The original building data overlaid with the new building data.
Fig 6. Using ArcScene, the data was then converted into 3D. Once in 3D the buildings were then extruded.