Q: How can I save and reuse elevation data for an area coverage study?

A: For radial and contour studies you can save the topographic elevation data along the radials used from a site, and then reuse the same data for subsequent studies from the same site. (Elevation data cannot be saved for tile studies.)

Normally, TAP retrieves and uses topographic elevation data along radials directly from the topographic data files. However, you can save the data for use later. This is especially helpful if you want to run a preliminary study and save the elevation data, then edit the elevation data to improve its accuracy (using the TAP Elevation Data Editor under the Editors menu), then run additional studies using the edited elevation data.

First, on the Advanced tab of the Area Coverage setup form, in the Topographic Data section, select "Save New Elevation Data" and enter a description of the data to be saved. This description will be used later when you want to lookup the saved data.

Then run the study. A data base of the elevation values, keyed to the coordinates of the site, will be created.

When you want to run a new study (from exactly the same site) using the saved data, go to the Advanced tab and select "Use Saved Elevation Data", then click the Lookup button to find the data you want to use:

If radial values are already defined, a warning message will be displayed:

Select the radial specifications by clicking the selection button to the left of each row. You can select the first radial, then hold the Shift key while selecting the last radial to select the entire list.

Click the Remove button to delete the radials from the list.

When the radial list is empty, click the Lookup button to find the saved elevation data for the site to be used in the study:

A form will be displayed listing all of the available saved data for the specified site. Select the data set you want to use and click the Continue button.

Then continue the study normally. The previously saved (and possibly edited) elevation data for the radials will be used.

If you save the studies for execution later (from the TAP File|Tasks menu), be sure that you execute the study where the data is to be saved first, so the data will be available when the other studies (using the saved data) are executed.