Routing issue with OpenStreetMaps with Map Source

[kujo4pm]

Hello

I'm planning a trip through the Caucasus and I'm testing out a GPS. I've been told that OpenStreetMaps is the best for this area but I keep coming up against some pretty serious limitations. For example even when plotting a route from Dresden to Prague - which I would imagine would be fairly simple MapSource just plots a straight line see image:


Is this an issue with tiling? Do I need to compile them into a single map before I upload them or is it just a limitation with the software? Apologies if this is a newb question.

Thanks.

[Toyark]

Best map would be Garmin's City Navigator but it is not free whereas OSM is.
Not all OSM maps/sections route. Some do, some don't depending on the level of data available/contributed.

You might also want to adjust your zoom settings.

[Sam I Am]

Where did you get the maps from and how were they installed into MapSource? It's possible to generate maps with routing data turned off. I'm not a MapSource user and so probably not the best to ask but a little red light went off when you asked whether you needed to compile your data into a single map.

I would suggest you go to Free worldwide routable Garmin maps from OpenStreetMap , go to the top of the page and select "enable manual tile selection". Mark the tiles you need, provide your email address on the left side of the page and watch your email. You will be sent a few messages, and a link after your customized map is generated. Download the MapSource version and install it. That may solve your problem.

Unless the OSM data is broken there, the routing will work. If the routing still doesn't work and it's not a MapSource issue, report back and I'll take a look at the OSM data in that area. Major routing problems like that are very rare.

[Sam I Am]

Just had a flash and tested the route Dresden-Prague using Routing Demo | Geofabrik . It is a site that is used for testing the OSM routing engine... as such, data is restricted to western Europe. No problems.

I think that your problem is either with your map source or your MapSource

[kujo4pm]

Hey Sam - yeah that's what I did: I highlighted the relevant tiles from Free worldwide routable Garmin maps from OpenStreetMap and downloaded the mapsource installation. I opened them in MapSource and this was the result I got. I noticed that small routes were not an issue (it maped the route correctly to roads) but longer ones were - just drawing a straight line between the two points. I was reading about intertile routes being a problem - perhaps this is what it is. I tried loading the maps onto my Garmin Nuvi 350 and when I tried the route (from Dresden to Prague) it said "Route calculation error" or words to that affect.

[Ekke]

I don't have the OSM maps for those areas but have just recently downloaded a whole bunch of OSM maps for our trip across Russia. I tried a route on a long distance from Kiev to a random town in Romania. Straight line. Interesting. I zoomed in on Kiev and the starting point for the route was not on a road. I then tried putting the route tool directly on a road in Kiev and the end point on a road in Romania and it worked.

Perhaps that's all that's happening with your route? Try using the Route tool to place the start and end points right on a road.

[Sam I Am]

I'm in the process of downloading that area now in order to check things out myself, but was wondering if you have tried bypassing MapSource by just downloading the gmapsupp.img version produced by the website and placing that file in the /Garmin directory on a chip. That's how I get the maps.

In general, though, routing across tile boundaries is not a problem. Splitter, the program that breaks raw OSM data into workable chunks, and MkGMap, the program that combines it all into MapSource or GPS usable formats, work pretty well together.

[Sam I Am]

OK... so I downloaded a new set of tiles between Dresden and Prague and surrounding regions, dusted off my Windows and MapSource and had a look. One thing I did, however, was delete the existing OSM map set that I had previously installed in MapSource. To do that I went to the /Garmin/Maps/OSM World Routable directory, and uninstalled using Uninstall.exe. I also deleted the .img tile files remaining in the directory (not sure that was necessary). I then installed the new map, making sure MapSource was closed. Started MapSource and had no problem with the routing.

Do you have any other OSM maps installed in MapSource? That may cause an issue. I understand that MapSource needs maps with distinctive "Family Names" or some such, and maps from Free worldwide routable Garmin maps from OpenStreetMap are always generated with the same default name. Installing two at once can cause problems I guess.

Ekke had a good point about zooming in and making sure that you were actually starting and ending on a road. Also, it took a good 30-40 seconds or so to do the routing. I had thought it hung. MapSource definitely does not have as fast a routing engine as the OSM engine.

[kujo4pm]

Hey Sam,

Yeah I installed it on another computer at home and it seems to have worked. Thanks for you help.

[Sam I Am]

Great, glad that worked for you.

If you're ever interested in rolling your own maps in order to customize them to your liking, take a look at Mkgmap - OpenStreetMap Wiki . It's a bit of a process and works best on a fast computer with lots of memory, but it is possible to make your own at home instead of downloading the pre-made ones.

I've had a lot of fun with it.