USING ArcScene FOR 3D VISUALIZATION IN THE CLASSROOM AND FIELD

ArcScene is an exceptionally useful, but underutilized, aspect of the 3D Analyst extension in ArcMap for visualizing both topographic and geologic data interactively in three dimensions. ArcScene can be used in a number of ways with different types of 3D data.

Base heights from DEMs can be used to create 3D images of corresponding digital orthoquads, digital orthophotos, and satellite images that can be rotated, flown through, and viewed from any angle. This technique can be used to help students visualize landscapes, the connection between topographic contours and 3D topography, and the correlation between bedrock geology and topography. In the field, 3D models in ArcScene can be invaluable for plotting traverses on imagery and for visualizing sample locations in their respective 3D positions.

A number of factors are crucial to creating a good model in ArcScene. First, 3D model quality will be best if the DEM resolution is appropriate for the scale of the image. The second key is matching the sun illumination direction in the model with that of the original raster image so that the artificial shadows and real shadows do not conflict. Date and time of acquisition for a given image (from the image metadata) can be input into NOAA’s Solar Position Calculator (www.srrb.noaa.gov/highlights/sunrise/azel.html) to determine solar azimuth and elevation at the time of imaging and be used to set the lighting angle in ArcScene. The third key to a high quality 3D model lies in the settings of the Layer Properties Rendering tab. Selecting “Shade area features” (which is unchecked by default) and changing “Quality enhancement” to High is crucial, although it takes lots of video memory.

Students can use ArcScene to plot point data in three dimensions. Being able to rotate the model helps students visualize the data distribution much more easily than by viewing a static perspective model. Earthquake data downloaded from the USGS Earthquake Catalog (neic.usgs.gov/neis/epic/epic_rect.html) for any location and time range can be imported into ArcScene and plotted quickly in three dimensions, allowing students to visualize the depth distribution of earthquakes. Similarly, data on temperature, salinity, dissolved oxygen, etc. from NOAA’s National Oceanographic Data Center (www.nodc.noaa.gov) can be plotted in ArcScene as a rotatable 3D model.