How to solve problems with VGA graphics

Geocomp uses two distinct screen display technologies, ANSI for most text and VGA for graphics.


Geocomp uses the Virtual Graphics Adapter to display most of the graphics screens such as the Spatial Data System, Main Menu and Road Design.

For graphics to display properly, the screen, video card, video BIOS and related drivers must all support standard VGA mode 12 (640 x 480 pixels and 16 colours).

Symptoms of non-conforming displays we have encountered include:

                        • All black
                        • All black in full screen mode
                        • Black with flashing cursor in top left
                        • Pulsing
                        • Missing part
                        • Relocated part
                        • Lock-up
                        • Transparent menus
                        • Invisible mouse cursor
                        • Multiple hourglass icons
                        • Flicker with mouse movement
                        • Big black borders
                        • Blurring
                        • Thick lines

If you have any graphics display problems in Geocomp like this, this is a hardware problem, that we cannot fix by software, so we suggest that you ask your computer or display manufacturer for advice.

Changing the Windows desktop resolution will generally not make any difference to Geocomp. However, try booting Windows Safe Mode which comes up in 640×480 without loading drivers such as video and Sentinel dongle drivers. This may get you past the initial display problem to find a Geocomp “security device not found” message.

If the problem is with the computer, it can usually be fixed by installing the latest video BIOS driver from the manufacturer’s web site. Even on a new computer, the installed drivers may already be six or more months old.

Sometimes, a different video card is part of the solution, however, we cannot suggest particular video cards to work with Geocomp, because the market changes much too quickly.

If the problem computer is a notebook, try using an external display. If you have a desktop computer, try swapping the external display.

If you have a wide screen, your circles will be ellipses until you adjust the display proportions at Configure Geocomp, Configure SDS Display.

Adding a DVI port makes it easy to have two screens running side-by-side in Windows XP. With this arrangement, Geocomp is displayed on your primary display. The secondary display may be black or may repeat the Geocomp shown on the primary display. To get back to to Windows, either exit Geocomp, or ALT TAB.