Worldwide blank map navigation on a pocketPC
Blank Map Navigation? Lots of people have a "GPS" and a fast growing number of them have a TomTom Go, or similar car navigation system. The real GPS enthusiasts have a handheld GPS receiver from Garmin, Magellan or similar, mapping or non-mapping. Between these two groups is a huge group of GPS users who utilize a pocketPC or GPS PDA to run a Navigator program for in the car and who use OziExplorer, Fugawi, or similar to use their own-scanned topographic maps for walking, hiking or biking in the great outdoors.
Scanning and calibrating maps is often very frustrating
For most parts of the world it is still hard to find suitable maps. And if you find a map, it often has a scale of 1 : 3 000 000 or worse and often there is not even a co-ordinate grid printed on the map. Or there is a grid, but you know nothing about it. What is the datum and what is the projection method? Especially older maps can have very unique datums. Trying to calibrate such a map is often deemed to end in frustration. Or, worse, you think that you calibrated it correctly and in the field your track is always several miles besides the road or trail on the map. And maybe the difference is not equal for all parts of the map. Blank Map Navigation is the solution here.
A blank map for GPS navigation
With your pocketPC you can use blank map navigation for the most exotic spot on our planet.
Large blank map step-by-step
For Blank Map Navigation, we will show you how we made one large blank map for the Benelux (Belgium + the Netherlands + Luxemburg). We used a 1 : 3 000 000 map from a world atlas. In a world atlas you find every spot on earth and all maps have a co-ordinate grid. We do not know the datum, but this is of no importance, as we do not use any mapping information. We only want to know roughly the longitudes and latitudes that our rectangular map will have to cover. Here is the map:
Map extract from Spectrum Wereldatlas.
© Uitgeverij Het Spectrum 1978.
From the map we learn that our rectangle will have to cover latitudes from 49° 30' to 53° 30' North and longitudes from 2° 30' to 7° 30' East. On the paper map in the atlas we measure the distances W-E and N-S in the middle of the map and find for W-E 342 km and for N-S 465 km. We know that these are three small countries, but this map will cover a surface of 342 x 465 = 159 000 square kilometers. One can walk and even drive around a lot in such an area. It also covers a nice part of the North Sea, so you can also use it on your boat.
How many pixels do we need for our map?
For the 35 x 45 km map of our region in the above article we had chosen 25 m per pixel in 100% zoom, which results in 2.5 m per pixel in 1000% zoom. This is better than any consumer GPS receiver will produce, so we decide that our new map will have 5 m in 1000% zoom, which makes 50 m in 100% zoom. So we have to create a blank image of 342 000 / 50 = 6840 pixels wide and 465 000 / 50 = 9300 pixels high. This is a large image.
In Paint Shop Pro or similar image editor we create a 2-color new blank image of 6838 x 9298 pixels and add to this a black border, one pixel large. Now we have our 6840 x 9300 image. To this we add a white border, 10 pixels large. The final image measures now 6860 x 9320 pixels and is only 25 kB on the hard disk. We save the file as "Benelux Blank.png" or .gif.
In OziExplorerPC we calibrate this new map with the latitudes and longitudes of the four corners of the black rectangle: 53° 30'N / 2° 30'E, 53° 30'N / 7° 30'E, 49° 30'N / 7° 30'E and 49° 30'N / 2° 30'E.
With Image to Ozf we create the files for the pocketPC: Benelux Blank.ozfx3 (532 kB) and Benelux Blank.ozf.map (4 kB). We transfer the files to our GPS PDA. Will it be able to handle this file and allow us to do Blank Map Navigation?
Field Test
Other than with the East Timor map, we can test this one in our own region. So we did a small trip and marked some waypoints. This is Blank Map Navigation. And, of course, OziExplorerCE immediately switched maps and choose our smaller blank map of our region, as it is more detailed (25 m per pixel against 50 m per pixel for the new map). It changed maps, because we configured it to always look for a more detailed map under the cursor. The first photo of the screen shows the waypoints and track on the small map "Blank page 1.png".
We changed the map to the new one "Benelux blank.png" and changed the zoom level. Remark that for the higher detailed smaller image the zoom level is 250% and for the large map it is 500%.
We transferred the track log file and the logged waypoints file to OziExplorerPC and on a "real" and calibrated map they look as in the next picture. The UTM squares on the map measure 1 x 1 km, so this proves that it was a very small trip that is correctly presented on our large blank map.
Conclusion
Making a detailed blank map for any rather large area of our planet is not difficult at all and this way you can use blank map navigation on your pocketPC with a GPS mouse or Bluetooth GPS receiver and on your GPS PDA.
Solution without the need to create Blank Maps
The following article shows a way to apply worldwide Blank Map Navigation without the need to create Blank Maps: The ultimate worldwide pocketPC GPS Navigation.
