How to get an offline map on your phone and use your phone as a GPS

When my last classic phone died and I replaced it with a new "smart" one, I was immediately interested in the possibility of using it as a GPS.
I tried every possible program I could find. Most wanted an online connection, so I paid for internet and tried further. Eventually I found out that this was not the way to go. The connection was (and is) poor quality, slow and relatively expensive, plus it tends to drop out at the exact moment you need it most. Although with apologies to the operators - where we like to go most (forest, creek cuts, roads ...) the sun doesn't even shine, let alone any signal from the transmitter.

I started looking for a combination of software and offline maps. In the end I stuck with Locus and I make my base maps in MOBAC (MOBile Atlas Creator). As a basis for fast and reliable orientation, I use a vector map that can be downloaded under the name czech-republic-20120218.map It is fast and, as I have verified, quite accurate. So far, it hasn't let me down, and I use it as a GPS when travelling around the Czech Republic - so far it hasn't driven me anywhere in the field like the latest map from the unnamed branded GPS manufacturer that I have in my car.

There is no point in describing both programs here, there are extensive discussions and tutorials on the internet.

Instructions for making a map in MOBAC for Locus can be found here: http://www.geocaching.cz/forum/viewthread.php?forum_id=7&thread_id=21539
Right at the top of the page you have a link to download the MOBAC program, including downloads of many of the underlying maps (including orthomaps and tourist maps), which I hope everyone can choose from. What I didn't find there are the maps we are interested in - the II and III military mapping and the historical orthophotomap from Cenie.

So I'll take the liberty of describing one way to get these maps offline on your mobile. I'm not a professional cartographer, nor a programmer, nor any kind of mobile app expert. Maybe someone has a better or simpler approach, but I've tried this and it works.

What we need:
1. A "smart mobile phone" with GPS and Android
2. MOBAC
3. Locus
4.A computer with an internet connection
5. Time and patience

Adding a map source to MOBAC - II and III military mapping.

Programmers and people otherwise knowledgeable can write their own xml code to attach the WMS layer. The rest of us pick some ready-made code (from the mapsources directory), and get to editing by trial and error. When the map we want appears in MOBAC, we can start making the map.
Just a technical note - Locus is said to work poorly with a map that is more than 2 GB in size. So it is better to make more maps in smaller units, it is probably not worth trying to make the whole Czech Republic in zoom 16. For information and idea - South Bohemia region, III Military, zoom 8-15 has about 1GB and the map took about four hours to create in MOBAC.

I managed to make the following connections for the II and III military mapping.

Simply copy the code into notepad (or another text editor that saves it as plain text) and save it under the selected name with the xml extension in the mapsources folder of MOBAC. The program must not be running. After copying and running the program, the source should appear in your map selection under the name given in the . The custom file name under which you saved this to the MOBAC folder is ignored by MOBAC.

Code for II Military Mapping:




II_MILITARY
8
16

PNG

1.1.1

0

http://mapserver.ujep.cz/ArcGIS/services/Geolab/IIVM_WMS/MapServer/WMSServer?

EPSG:4326

&Styles=
#000000


Highlighted (edited parts):

II_MILITARY
This is the name under which it appears in my program. If it doesn't appear, there's an error somewhere. Either I deleted something, or I overwrote something, or the editor saved it with some other extension (e.g. II_vojenske.xml.txt).

8
At this zoom I can see the whole map on the screen.

16
There's no point in higher resolution, even the 16 is with a question mark, I think 15 is enough for reference.

http://mapserver.ujep.cz/ArcGIS/services/Geolab/IIVM_WMS/MapServer/WMSServer?
Address to the WMS server containing the required data. Various WMS servers can be found via Google, and then just experiment ....

Code for III Military Mapping:




III_MILITARY
8
16

PNG

1.1.1

0

http://geoportal.gov.cz/ArcGIS/services/CENIA/cenia_rt_III_vojenske_mapovani/MapServer/WMSServer?

EPSG:4326

&Styles=
#000000

And how do you get a historical orthophoto map on your mobile?

I'm sure you all know the site kontaminace.cenia.cz with a beautiful historical orthophotomap from the 1950s.
It's not so easy with that one anymore, because Cenia is not allowed to provide this map as a WMS service based on licensing conditions (I recently checked. I use the map at work, where we have
stored on a map server, and I would occasionally need it for off-site meetings. I raised the query with Cenii and got this response).

But a certain cutout is relatively easy to get into the navigation:

We need some program that can calibrate (georeference, adjust ...) the images. MAPC2MAPC is most often recommended. It's shareware, so you have to buy the full version for 10 GBP, otherwise the output will be like this:

10 GBP is at the current exchange rate some +- 300 CZK. If this is too much for someone, or if they don't want to pay someone via the internet, they can use the freeware program OkMap:

Procedure:
1. Find, download and install OkMap (http://www.okmap.org/en_download.asp), there is also a tutorial.
2.On the website kontaminace.cenia.cz you can find the desired area - I chose the centre of Jílovy u Prahy for the example - out of respect for the hunters.
3. Save the selected cutout via the Export Map button. It will offer you the name of the km without the extension - so change it to the desired name and add the png extension (Jilove.png).
4. Keep the pages open, we'll need them for calibration in a moment. Run the OkMap program.
5. Select File - New - Raster map from the menu. A classic browse window will open, find our image - Jilove.png
6. The image will load and the calibration window will appear at the same time. To make the output look like something, it wants at least 4 points as close to the corners of the image as possible. The more points, the better the calibration.
7. I chose 4 points (something a bit distinctive that can be found on the original map). Then it's easy - I set the calibration point in OkMap to the desired location, go to the contamination pages, click on the same location and the coordinate window will show WGS coordinates of that location, copy to clipboard, click on OkMap, paste the coordinate and watch out - don't forget to overwrite the decimal point with a comma (if you have CZ wokna).
8. When I have enough points, I click Accept and the image appears as calibrated. File - Save map.
9. The next step is to convert the acquired map to a format that Locus understands - in this case it is the KMZ format.
10. In the Utilities menu I select Map tiling / Garmin custom maps.
11. A new window opens, in the upper left corner I open the saved Jilove.okm file and save it as KMZ (via the Generate button - pyramid on the right).
12.
If I am satisfied with it, I upload it to my mobile phone to the Locus\mapItems directory. I can turn on the map from the Maps - Items tab.

Map calibration in OkMap:

Export map to KMZ:

Test in Google Earth:

Turning on the map in Locus and displaying it:

What to do at the end?

I'm using a Sony XPERIA NeoV phone, which is, let's say, a mid-range phone. I only use GPS via satellites (and I have verified that it's free) and the accuracy of targeting in the field is about 3-5 m, in the forest depending on the situation, but often you can get within 10 m. I think this is more than enough to find the place again.

I am not a promoter of any of the above programs and am in no way affiliated with their providers. It's just my advice for someone who might have thought of making something similar, or doesn't want to lug another device.

The programs and data used are in the public domain, so I believe that as long as you do not use the above methods for commercial activity, but only for your own use, you are not committing a breach of the license terms. So everything is free and legal.

Mivl

And while you have the map on your phone, don't forget your metal detector at home.