First, you can compute the coverage and extract the topographic data from TAP, then use SURFER to plot the two types of data together.

Topo Data Area Grid

From the Topography menu, select Area Grid:

The Area Elevation Data form is displayed:

This form is used to set up the area you want define for creating a SURFER grid file. SURFER can use grid (.GRD) files to create contour or 3-D surface maps.

Click the New button to create a new task for retrieving the area grid data. You can manually enter the parameter values for the area grid, such as the coordinate boundaries and the increment or "step" of the data along each axis.

Since we will want to use the same coordinates for the coverage study, use the Template button to create a template to save the grid area boundaries. Click the Template button. The Tile Study Parameters Template form is displayed.

You can use this form to create a new template area, or to select one you entered previously. In this example, we will use the Metro Denver area as shown.

To select the area template, click the Close button. The area boundaries are returned to the Area Elevation Data form:

When the area grid data parameters have been entered, click the Save button. This will save the task information. In this example we will set up both the topographic and the coverage tasks, then execute them together.

After the Area Grid data is saved, click the Close button on the form.

Coverage Calculation

From the Coverage menu, select Area Coverage.

The Area Coverage Setup form will be displayed.

This form is used to set up the parameters for a coverage study. Click the New button to create a new coverage task.

Enter the parameters for the area coverage calculation, such as the base station or fixed facility information, the propagation model, mobile unit specifications, etc.

Since we want to specify a specific rectangular tile area that is not centered on the transmitter site, be sure the Use Advanced Settings option is checked.

To enter the area boundary limits for the coverage study, click the Advanced tab.

The Advanced tab enables you to enter the customized coordinate limits for the area to be computed.

To use the same area as previously defined for the topographic area grid, click the Template button.

When the Tile Study Parameters template is displayed, find the same template for the topographic area that was used for the area grid data. Click the Close button.

The area limits are returned to the Advanced tab of the Area Coverage Setup form:

Click the Basic tab, then click the Save button to save the task.

After the task has been saved, click the Close button.

To execute the Area Grid and the Coverage tasks, click the File menu and select Tasks:

The TAP Task List form is displayed:

Select the tasks you want to execute, and click the Add button in the Tasks To Do section. The tasks will be added to the list:

When the tasks you want to execute are in the list, click the Execute button.

A progress indicator will be displayed during the execution of each of the tasks.

When the coverage study is finished, click on the Coverage menu and select Export Coverage to SURFER Grid:

The Select TAP Task form is displayed. Select the tile coverage task you want to plot in SURFER:

Click the Continue button to select the task.

The Export Coverage form is displayed. Be sure the X-Y Units are set to Lat-Lon. The units of the Area Grid and of the Coverage must be the same to combine the plots in SURFER.

Click the Close button.

Enter the name of the SURFER Grid file you want to write:

Click the Save button.

The progress indicator is displayed while the coverage information is written to a SURFER Grid file:

When the export is complete, you can exit from TAP and start the SURFER program.

To plot the 3-D topographic surface, click the Map menu in SURFER and select Surface. Select the grid file you created with the topographic data.

Accept the SURFER default settings for the plot. The area elevation data is plotted:

Next, add the coverage information to SURFER. Click on the Map menu, but this time click Contour.

Select the grid file for the coverage information that you exported from TAP.

Use the Contour Map form in SURFER to select the colors and levels you want to plot. For example, if you have determined (using the TAP Compute Required Field function) that you want to see the levels of 20dBu, 40dBu, and 60dBu, you can specify these levels, with a color assigned to each level.

On the SURFER Contour Map form, be sure the Fill Contours option is selected. This option will draw the assigned color for each level over the appropriate area. If the option is not selected, only the contour lines themselves will be colored.

When you have made the settings you want, you can draw the coverage contour map in SURFER:

If you want to make changes to the coverage contour map, double-click the map and the Contour Map form will be displayed so you can change the settings.

For example, if you want to remove the contour lines, just leaving the colors, you can double-click and change the line settings. The contour map is redrawn as shown:

To combine the area coverage contour map and the topographic surface map, click the topo map on the SURFER drawing, then hold the Shift key and click the coverage map. This will select both maps. Then click the SURFER Map menu and select Overlay Maps. The Overlay function in SURFER combines the maps to the same scale and orientation.

You can use the SURFER Map|3D View function to change the orientation of the drawing:

If you want to add boundary files, click the SURFER Map menu and select Load Base Map. Select the file you want, such as a .BNA boundary file from TAP.

The boundary file will be displayed as a separate map.

You can double-click the map to change the color, line properties, etc.

When you are ready to combine the boundary ("base map") file, click the maps to select all of them, then again use the Map|Overlay Maps item.

If the base map boundary lines do not show on the 3-D plot, select Map|Edit Overlays. A list of the different components of the drawing is shown. Select the "Base" option, then click the Bring to Front button.

If you want to change any of the properties of a part of the drawing (such as the coverage levels to plot, etc.) you can select the Edit Overlays option and choose Break Apart. Then edit the drawing components as desired, and use Overlay Maps to re-assemble the drawing.

For example, to add a legend of the field strength values, break apart the drawing and select the coverage contour section. Double-click to display the Contour Map form, and select the Color Scale option. When you select the maps to use the Overlay Maps function, do not select the color scale. This will enable you to position the color scale anywhere you want on the drawing.