LXGPS Map Conversion and Calbration notes.

The following is a list of steps using Delorme Street Atlas, IrFanView to Pre-Prepare map clips from any map display software for use with Dos LXGPS software.  Note!  The maps generated with any propritary software program are themselves propritary and copyrighted.  The following assumes that you have purchased the rights to the program that generates the maps.

The steps below use Delorme's Street Atlas as an example of a Windows clipboard clip of a currently displayed map, but you can use Windows to capture clips of displayed maps generated by any software.  Delorme has the option "Copy Map to Clipboard" in the edit menu.  If other map software does not offer this option, press <Alt-PrintScreen> to generate a clip.  In addition to capturing the map, <Alt-Printscreen> will capture the toolbars, menu and borders as well which can be "cropped" using the IrFanView program below.

While the Delorme map images and clips are full color, the LXGPS software will be displayed on a black and white LCD screen, so the maps have to be processed from color to black and white, and then converted to a "1 bit" black and white PCX file.

The Delorme display colors create a complication to this process.  Delorme's default background color is light yellow and a high percentage of the roads are displayed in red.  While this provides great readability in color, when you attempt to convert to black and while, yellow and red "contrast" in the same direction resulting in all red streets disappearing into the yellow background.

While I have accomplished the image processing with a variety of image programs, the freeware image program IrFanView is universally available, free, easy and has all of the tools necessary to complete the conversion from a Delorme color clip to a 1 bit pcx file.  Most importantly for this process, it provides a complete set of tools to deal with both the red/yellow contrast and the direct generation of a 1 bit PCX disk file.  IrFanView is available at available at http://softwarecenter.net/irfanview/

Basic Windows Setup Before Copying

Set your Windows Desktop to maximum pixel resolution.

For larger images, use "Virtual Desktop" if available (you may have to reduce colors)

Preparing to Capture a Map Clip from Delorme Street Atlas

Start and Maximize Street Atlas

Turn off all toolbars and status bar

Size and position the map to display the area you need to convert. (Scroll to confirm if using Windows' "Virtual Desktop")

Select "Copy Map to Clipboard"

Paste into image editor (IrFanView)

Return to Delorme (Note avoid normal "Left Clicking" in Delorme as this will reposition center of map)

 Pick and note the names two landmark "diamond" marks near opposite corners of image you just copied.

Zoom in to maximum resolution on each of the landmark diamonds you picked.

Right Click on landmark and select "Lat/Long on Map Note."   (Note, if you did not "zoom in" to the maximum resolution, the precision of numeric Lat/Long value on the map note is not going to be very precise.)

Right Click resulting "Note"

Select Properties

Copy Lat/Long and paste into text file for future reference

Repeat for second diamond

(Note... for maps displayed by other applications that do not have a copy option, press the <PrtScreen> key to copy the current screen to the clipboard)

Converting Map image to a 1 bit PCX File using IrFanView

Time to process the image you pasted. 

Select "Greyscale"

Select "Sharpen" several times (to your taste)

Select Image/DecreaseColorDepth

Select 2 color

Save as PCX file.

As an example of the processing of the colors, note the street in red and the small rectangle of side streets near the lower left corner of the example above and compare the change in appeaance though the process.  In addition, note the light green area along the left border.  The "sharpening" process is necessary to keep these areas from swallowing up the greyscaled streets.

Final Stretch... the LXGPS Calibration Process

On the LXGPS menu, Specify the PCX Map File Name you generated with IrFanView in Settings/Files/Map

LXGPS will automatically go to "Calibrate" mode with "crosshairs" at upper right of map

Find the diamond near the upper left of the map clip that you identified when you made the map clip in Street Atlas.

The pixel structure of these "diamonds" will fit exactly into the LXGPS map "cross hairs"

In LXGPS, the cursor moves about 5 pixels per cursor arrow press... When the crosshairs get close to the diamond, use <Shift-Arrow> for 1 pixel movements. (If running on non LX machine, numeric pad must be used instead of cursor pad for 1 pixel movements.)

Don't move too fast... if you go off of the lower or right corners of the map, a divide error will occur.

Select "point-1" and enter lat/long that you saved during the Delorme part of this process in following format;

N 30 58.946
W 98 42.444

Repeat using the diamond near the opposite corner for "point-2"

Select "Calibrate"

Select Invert for LCD displays

Select Save

Select Done

Exit LXGPS to assure CFG file settings are written

Repeat for each map


The above process will result in an amazing level of accuracy on the HPLX.  On maps where the width is about 40 miles, the GPS tracking cursor is precise enough to indicate which side of a interstate you are traveling on.  In addition, LXGPS allows you to "zoom in" to more detailed maps.  You can generate a county map, and then generate downtown maps that are 20 times more detailed and use a single key to have LX automatically pick the appropriate map and display it with the GPS tracking information continuing.

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