View Full Version : DIY electronic ICAO charts for a portable GPS


Ultranomad
10th May 2012, 20:28
In recent months, I have been experimenting with various GPS solutions to supplement my onboard GNS 430, which is a good piece of kit for IFR, but not always so for VFR. One of the hardware platforms I tested was a Chinese navigator with SiRF Atlas IV chipset (http://www.dealextreme.com/p/5-0-touch-screen-wince-6-0-gps-navigator-w-fm-sd-slot-black-blue-4gb-67146) running Windows CE. The device itself is very decent and more than worth its price of $70.
Of the sofware I tried, SkyDemon was an undeniable leader in terms of functionality, but it was just too slow, so I settled on the old trusty OziExplorer, and will probably be using it in my routine flying.
An electronic ICAO chart for Germany (plus adjoining areas) for this year was pulled off the web. It does cover my base airfield in Czech Republic, but not much further eastward, so I embarked on making my own ICAO chart of Czech Republic.
Air Navigation Service of the Czech Republic (http://lis.rlp.cz/) does offer a current airspace chart in PDF format (http://lis.rlp.cz/info/ANC_ICAO_2012.pdf) for free download, but it's only an airspace layer in Lambert projection, without the underlying topo base, and the file is not georeferenced. I opened it in Global Mapper and calibrated it by hand (took me 10 minutes), then started looking for a suitable base map. As it turned out, there are quite a few maps available for free download. My favourite ones are a 1:500000 Land Cadastre topographic map available through WMS from http://geoportal.gov.cz/ArcGIS/services/CENIA/cenia_rt_RETM/mapserver/WMSServer and the World Topo Map (a link is included in Global Mapper). The former is more informative (and ostensibly more accurate), the latter is sharper and better coloured. Here is how to make an ICAO chart out of the above:
1. In Global Mapper, load the base map as the bottom layer and the airspace on top of it.
2. To make the airspace borders clearly visible, use the control centre in Global Mapper to lighten the base map layer to your own taste (I used -100 for colour intensity).
3. Set the blending mode of the airspace layer to "darken" (also in the control centre). Play with other display parameters if you want.
4. Once satisfied with the look of the overall combination, export it into GeoTIFF.
5. Import the GeoTIFF into the desktop version of OziExplorer, creating a .map file.
7. Use Img2ozi utility from OziExplorer to convert the GeoTIFF into .ozfx3.
8. Load the .map/.ozfx3 set into your navigator and check if you like how it looks.
9. If an additional colour correction is necessary, you can just edit the GeoTIFF in an image editor. The calibration is already stored in the .map file and won't be lost. Then go back to step 7.
10. If the default scale on the navigator screen is inconvenient, go back to step 7 and change the initial resize factor.

As it turns out, EU has recently mandated all member states to create public geoportals, and this is where one can hope to get standard base topo maps for free; if none is available, one can always use World Topo Map. Now, the question is about the airspace layer. So far, I am only aware of the Czech one in PDF format. There are digital airspace descriptions avialable for many countries, but I am not sure whether they can be easily transformed into nicely looking graphic images. Your input on that will be greatly appreciated.



Jan Olieslagers
10th May 2012, 20:36
I am angling in the same pond, and recently came upon Worldwide Soaring Turnpoint Exchange: Airspace (http://soaringweb.org/Airspace)
I intend to import data from there into my homebrew GPS, which is written in C and runs on Ubuntu Linux on an eeePC. Not clear when and where I will find the required time, though.

Feel free to get in touch!

Ultranomad
10th May 2012, 20:41
Jan, I found the same site yesterday :) The only question is how to make nice images out of those files - you can get the airspace borders themselves, but things like runway characteristics, radio frequencies, shading in the restricted/prohibited areas, isogones, etc. remain to be done by hand.

Jan Olieslagers
10th May 2012, 20:57
question is how to make nice images

Beauty is handcrafted, by its very nature. Nice presentations are nice to have. I'll be proud and happy to have accurate and reliable data, presented in a manner a pilot can use. Everything else is icing on the cake, expensive (in time! my precious time!) and not really required.

And of course the site mentioned is about airspace only; for other information other sources are required. I am typing some into a spreadsheet table, and am VERY grateful for the French guys that make their data available in the same form, even if it takes some polishing.

Prop swinger
10th May 2012, 21:06
Why not just use software designed to display the data?

XCSoar (http://www.xcsoar.org/) is free & very configurable. You will have to make your own waypoints though.

Ultranomad
10th May 2012, 21:23
Prop Swinger, thanks! It's a pity the powered flying community is rarely aware of the useful developments in the gliding one. Another good example is FLARM - it could certainly be very useful to the powered GA as well, but only if most aircraft had it.