GPS points on regular maps - countrywide.

[Chuangt2u]

Whether you've been wandering in the Cardamons, 7 days from the road in Virachey, out on the islands, or lost somewhere in Mondulkiri reserve, see your position via GPS coordinates or tracks very accurately on fully-featured maps that cover the whole country.
Take a netbook and GPS handheld unit with you and see your exact position in the country on a regular map.

Follow the steps below to install the system on your computer - it's a 20 minute job, plus map downloads.

1. Download and install Quantum GIS
in Ubuntu, go to Applications > Software Center > QGIS
for Windows, Download the .exe file from here and install it.

2. After installation, start QGIS (Ubuntu - Applications > Science, Windows has a desktop shortcut installed) and go to Plugins > Fetch All Python Plugins and install all available plugins.

3. Create a folder on your computer called GIS

4. Go to CambodiaMaps click on and download the Index Image.jpg and the Index Image.wld files - place them both in your new GIS folder. The displayed image is the .jpg file. The .wld file tells QGIS how to position the .jpg image - the Index Image is just a guide, but the maps are accurate to within a few meters.

5. In QGIS, go to Layer > Add Raster Layer > navigate to your GIS folder > select the Index Image.jpg file.

6. Maximise the QGIS display area, right click on the top, grey toolbars and deselect everything except: Layers, Map Navigation.
Next, click "Zoom Full".

Your screen should now look like this... (in Ubuntu)



Click File > Save Project As and save to desktop.
In Windows, now delete all other QGIS desktop shortcuts as this will be your program start-point.

To view available maps in QGIS, scroll down this page and download both the .jpg and the .wld files to your GIS folder. Add the map.jpg to QGIS in the same way you added the Index Image above. In the Layers window, click and drag the Index Image and place it at the bottom of the list of maps.

Zoom by using the + or - symbols and clicking on the map, or by selecting + and click/drag/select a square on the map to zoom directly to that square.

Below are some links to files containing GPS tracks. Download and save them to your GIS folder, then load them to QGIS via the "add delimited text layer" plugin in QGIS. Plugins > Delimited Text > Add Delimited Text layer > navigate to your GIS folder and select the file
Keep the text files at the top of the list in the layers window.

Andoung to Koh Kong

Chuuk to Kep

Kho Neak to Banlung via Lumphat

To view your own tracks and GPS coordinates, save them to a text file in the same format as the above examples (UTM - zone 48 north), place the text file in your GIS folder, and display in QGIS as above.

The following photos show map number 6435 and the above Kho Neak to Banlung via Lumphat trail.











Continued to map 6335...

[Hoopharted]

Any chance you have the calibration files for Oziexplorer ?

[Chuangt2u]

Sorry, mate - I don't have them for Oziexplorer

My calibration files (world files) are for QGIS.
Try them - see if they work... they're the .wld files here - I've no idea if they'll be any good for Oziexplorer though.

[Typhoon]

Been looking into doing this for a while, any advice on which GPS to get for the Cambodian terrain? How good are the ones with a camera so you can link photo with location? I'm currently in the UK and thought I may be better off buying one here before returning to Cambo.

[Chuangt2u]

PM member "Arunadude", he knows far more about that than I do.

http://www.khmer440.com/chat_forum/memberlist.php?mode=viewprofile&u=3367

It's been a while since his last post, but he's still around, I believe.

[Hoopharted]

Sorry, mate - I don't have them for Oziexplorer

No probs. DO you know the map projection and map datum that was used and I will calibrate them for Oziexplorer (and send you the calibration files if you want to host them)

[Chuangt2u]

That info is on the maps...



Sure, I'll host the Oziexplorer calibration files . Mail them to cambodiamaps AT gmail.com

Cheers

[shitegeist]

That info is on the maps...



Cheers

... but that doesn't mean the digital images in your GIS remain in that datum and projection. It depends on what data you used to georeference the images against in your GIS (?). If GPS data aligns nicely then I'd strongly suspect that the images are now actually in WGS84 datum, UTM Zone 48 North.

[Chuangt2u]

When the images are displayed in QGIS using my georeferencing, yes, they are in WGS84, zone 48 north - but that's just QGIS setting the image against that datum by using the world files I supplied... (QGIS can display the maps in any datum once the maps have been referenced in any datum.)
For Hoopharted, he would have to georeference them against whatever datum he wants to use or has the data for. To do that, he needs to know the original datum the map makers used, or he needs to already have reliable images/data to georeference the map images against. The image doesn't change; the mapping software fits it into whatever display reference system/datum the user wants.

[shitegeist]

When the images are displayed in QGIS using my georeferencing, yes, they are in WGS84, zone 48 north - but that's just QGIS setting the image against that datum by using the world files I supplied... (QGIS can display the maps in any datum once the maps have been referenced in any datum.)
For Hoopharted, he would have to georeference them against whatever datum he wants to use or has the data for. To do that, he needs to know the original datum the map makers used, or he needs to already have reliable images/data to georeference the map images against. The image doesn't change; the mapping software fits it into whatever display reference system/datum the user wants.

Right, but what Hoopharted wants is your world files to translate... in which case the datum/projection of the original maps is irrelevant, and the important info is what coordinate system your world files are in. I assume they must be in WGS84/UTM48, and not Indian54/UTM48, because world files don't store coordinate systems and so you'd have to go through an additonal step to tell QGIS that your map is Indian54 to display it correctly in relation to GPS data...?

[Chuangt2u]

Yup, I think I see what you mean... in which case, I missed an ambiguity here -

Sorry, mate - I don't have them for Oziexplorer

No probs. DO you know the map projection and map datum that was used and I will calibrate them for Oziexplorer (and send you the calibration files if you want to host them)

I georeferenced the maps using WGS84 / UTM zone 48 north data, so my worldfiles for QGIS will display the maps in WGS84 / UTM zone 48 north in QGIS. I checked my georeferencing against random Google Earth feature coordinates for each map (road junctions and river branches) and also against random GPS tracks/waypoints/POI that I took from the internet - one of those random-check GPS tracks is shown going through Lumphat in my OP.

The map makers used



My bad - should've seen that one.

[Hoopharted]

That info is on the maps...Cheers

Ahh, different map set ... Not for the RCG roadmaps I downloaded from you here ..

http://cambodiamaps.blogspot.com/2009/0 ... nload.html

(well I checked 3 maps randomly and no datum or projection info. that I could see

Which are the better maps for touring by car/motobike etc ?

[Chuangt2u]

Hahaha, ok.

I wouldn't use the RCG roadmaps with Oziexplorer; they're nowhere near accurate enough, but they're good enough to be a reference guide without GPS. Another set has been produced recently that shows new roads and renamed roads, but I don't have that set yet.

If you've a laptop in the car and have Oziexplorer or want to try QGIS, then use the JICA maps downloadable from here
http://cambodiamaps.blogspot.com/2010/12/gps-coordinates-accurately-displayed-on.html

If you're on a bike and have a GPS system, then there are various options from taking your chances with the freely downloadable GPS datasets on the internet, or getting the fully supported and licensed commercial Garmin product from Aruna Technology in Phnom Penh.

If you're on a bike and traveling tech-light, then get yourself a paper Gecko Map, they're available from various places in PP - Monument Books has them, iirc.

[nightmare.believer]

I have a Tom Tom GPS. Do you think it can be cracked to add cambodia maps to it?

[Chuangt2u]

I've no real idea, but would suspect that the maps would need to be calibrated in a way to suit your device, and I highly doubt that the software for doing that came with your GPS unit - it's basically just a viewer.

I used QGIS open-source GIS software to display these maps for precisely that reason - it's designed to let you input data and is not a protected or closed proprietary system. The main drawback, though, is that you need to get your hands a little dirty and do the work that the GUI in commercial devices helps you with or their software handles automatically... for example, the Oziexplorer system will automatically jump to the next map and can remove map collars when you're moving between maps on the ground.
QGIS has many functions - but you need to do these bits and pieces yourself manually. It's not that difficult once you've figured it out and there's an instruction manual and tutorials to help with that.
http://www.qgis.org/en/documentation.html

It all depends what you want, really. Drop a system in your car and push a button and go, or get more involved with what that system's doing.