Image Preparation
Before you can register a map image you must first scan the image(s) of the map(s), or alter an
existing image you have, to ensure compatibility with the Barrett 977 Software.
The map must be scanned in using an external graphics package.
This map must have two or
four known points, identifiable on the map and defined using latitude and longitude or
AMG co-ordinates to enable registration into the Barrett 977 System.
The map images may be in the following file formats; BMP, PCX, TIF, TGA, JPG, GIF or DIB.
These file formats are identified by their extension. Note that PCX, TIF, GIF and JPG employ
some form of image compression and may take longer to display. The smallest of these is JPG
and picture quality can be lost with this format. Images should be saved as 256 colours. Images
with more than 256 colours may not display correctly.
Large maps can be scanned in sections and then registered with the same map level. For
example, each state of Australia can be scanned in separately at the same resolution, registered
with 977 and set to the map level ‘AUST STATES’.
The size (in pixels) of the maps is very important as the maps are displayed in their normal
resolution (or greater) on the screen, ie. if your screen is 800 x 600 pixels and your map is 1600 x
1200pixels you will only see ¼ of the map, you cannot zoom out. It is advised that you scan the
map in at the maximum resolution that you will require, then resize the map in your graphical
editor to create the resolutions you need for the different mapping levels, ie. have the first level at
800 x 600 pixels, the second at 1600 x 1200pixels and so on until you reach the resolution you
require. This will allow you to see the entire map at the first map level and to increase the
resolution if need be. Store the images in the Internav directory.Run the Barrett 977 Internav
program. Now it is necessary to register the map images as useable map-levels using the
registration process described below.
Installing the map images
Image registration is relating (geo-referencing) an image (produced using the process described
in Image Preparation) to two or four known positions defined using latitude and longitude or AMG
co-ordinates.
From the
Registration Menu
select either “Add to Register - 2 points or 4 points”. For best 2
point results select the points from the bottom left and top right corners of the image, respectively.
For best 4 point results select the registration points as close to the 4 corners of the image as
possible. Four point registration is selected mainly when working with conic coordinates.
Click on “Load Image” button and select a map image from the image selection file. The map you
wish to register is then displayed on the screen. A cross hair cursor is then displayed on the
screen. Place these cross hairs in the position of the first known point of latitude and longitude
and press the left mouse button. The following screen will then appear:
BARRETT 977 VEHICLE TRACKING SYSTEM
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