Adding Overlays

Adding Geodata Overlays

To add Geodata Overlays to a frame in INTERDLG simply click the check box for the geolayer you wish to add and then click the "Add" command button. INTERDLG will prevent you from adding a layer twice unless you defeat this feature by clicking a geolayer check box as many times as it takes to return the check mark to the box.

The following layers are available in INTERDLG's basic package:

State Borders Colored Dark Blue

Shorelines Bright Green (Does not include islands)

County Lines Dashed Purple

County Names Light Blue

US Cities Bright White (larger evenly spaced cities)

Every City Bright White (32,000)

4 Lane Highways Bright White (Bureau of Transportation Statistics)

2 Lane Highways Gray White (B.T.S.)

Lakes & Islands Light Green

Railroads Rust Red

Rivers & Streams Green

The US Geodata overlays have been digitized by the Department of the Interior, US Geological Survey from an original scale of 1:2,000,000 maps. Of course the data is re-scaled each time you use it to fit the needs of the frame you draw.

Adding Tic Marks & Labeling

If you check the "Tic Mark" box INTERDLG will place a "+" mark at each major latitude and longitude intersection point.

Enabling Tic labeling will identify each tic mark with its latitude and longitude .

Cardinal Radials Overlay

You may also check the cardinals box within the geodata overlays frame. This will cause the computer to ask you if you desire a cardinal radial lines drawn at even intervals from the transmitter site. INTERDLG draws its cardinal radials from 3 km to 16 km and then leaves a small blank. The cardinal lines then continue on to cross the station contour. If you carry out a new coverage study and have "cardinals" selected the program will ask you if you want to place a cardinal radial through the city of license. If you respond yes the program will ask you to pick out the city of license from the cardinal city screen.

The following additional overlays are optional:

Airports Overlay:

Public, Private and Military with three letter designations

Population:

Block Group statistics, PL 94-171, Code 740, coded to race

Towers:

FCC Antenna Survey Branch database, coded to height

By turning on the "Show Values" switch on the "Map Default Set - Options" screen you can set the program to display the text information next to the symbol used to represent the overlay object. For airports the designators plotted next to each symbolic "A" represents the airport's identification. Adjacent to each population symbol is the block value for the population centroid. For towers, the coordinates and height above mean sea level can be displayed adjacent to the tower symbol. To read these plotted values the user needs to zoom in on the symbol of interest.

Duopoly Overlays

AM (1 and 5 mV/m groundwave signal contours

FM (1 and 3.16 mV/m F(50-50) signal contours

TV (Grade A and Grade B F(50-50) service contours