Point Selection & Verification

Point selection can be done with the mouse by roaming over the map, watching the coordinates in the panel at the bottom of the window, and double clicking at the desired location. The accuracy with which you can select locations will depend upon:

• The scale of the DEM
• The size of the window on the screen
• Your manual dexterity

With a large DEM or a small window you may not be able to be very precise—you can only select those points that exactly correspond to pixels on the screen. The screen pixel size shown on the Information menu choice will show you the resolution with which you can graphically select points--note this is a best case, and assumes you actually can pick the pixel you want.  You can increase your precision by setting the Verify Coordinates setting on the Coordinates  tab of  the options menu. This offers the following choices:

• None: all coordinates selected with the mouse will be accepted. This will provide the fastest operation, but potentially lowest resolution. 
• Reasonable: coordinates where you might want to be the most precise (e.g. weapons fans or line of sight placement) will be verified. You have two choices, described below, for verification.
• All: any coordinate will be verified. This will probably be overkill, but if you wanted two three dimensional views to cover exactly the same ground you should select this option.

You have two ways to verify coordinates (also set on the Coordinates tab of  options menu):

• Graphical blowup: you will get a contoured blowup of the region around the point you selected with the mouse. Select the exact point you want by double clicking on the blowup map.
• Keyboard selection: enter the exact coordinates you want, with the mouse selection as the default. This does not let you verify that the hill top coordinates read from your map or GPS receiver are in fact those in the DEM.

Last revision 12/3/2011