mkgmap

Over a year ago I announced that mkgmap would require Java 1.6 "soon". Well that time is now finally here and further releases will no longer work on Java 1.5

Increasingly, as OSM gets bigger and bigger, people are having to face the problem that a map has to be split into tiles. There are various approaches that can be used, notably osmcut, and they work well enough at producing a map set that works. ... [More] However to produce the best map additional features are desirable. I not really interested in getting into the realm of splitting up xml files, but given its increasing importance I wrote a utility to split a large OSM file up into tiles in a way that is suitable for creating Garmin maps. I'm really hoping that others will look at this and do something better. First of all, lets look at the features that I think are essential when splitting into tiles. Adapts the size of each area based on the amount of detail present. There is a maximum size that each .img file can be. If you divide into equal sized pieces then you have to choose that size based on the most densely populated part of the map, leading to many small tiles. By having variable sized tiles, you can cover a whole country with a small number of tiles without hitting the dreaded 'Map too big' message. Breaks maps on exact low zoom boundaries. Latitude and longitude values have to be rounded to particular integral amounts. At high zoom levels the resolution is a matter of centimeters on the ground. At low zooms however the possible divisions are a considerable distance apart. The tile boundaries are recorded at a low zoom in the overview map and so unless the positions are exact at the zoom level on the map, they will be either overlap or have gaps when the boundary is rounded to the nearest unit. Features are cut exactly on the boundary. The resulting tiles do not overlap, nor do they have gaps between them. A road that crosses from one tile to another will be cut exactly on the boundary, and one part will be in the first tile and the other part in the second. Polygons are are also cut into two (or more) polygons, each sharing an edge at the tile boundary. A line that crosses a tile corner, but does not actually have a point within the tile will still be included. Although not essential, this splitter also has the following features: The calculated areas can be saved and re-used in another run. This is so you can produce an updated map that has the same tile boundaries. A template arguments file is produced that can be given to mkgmap with the -c argument to prepare the maps. It can be edited to describe the areas more accurately (for example the town or area the individual map tile covers). Can set the maximum number of nodes that are contained in each tile. To achieve some of these points, the splitter and mkgmap work together. The splitter calculates the exact file boundaries and places a <bounds> element in the .osm file with these exact coordinates. The splitter however extracts a somewhat larger, oversized, area into each .osm file and leaves mkgmap to cut the features exactly on the boundary. This overlap must be large enough so that there are nodes outside the boundary for every feature that crosses more than one tile. The default oversize amount works fine in towns, it may need to be increased in areas with widely spaced nodes. Other desirable features that you might want in a tile splitter, that are not catered for with this one. Ability to adjust the areas to match geographical areas or counties better. With the automatic way of splitting areas up, they may be hard to describe as they can cut across cities or countries in ways that are inconvenient to describe. Even an automatic way of determining the areas might be better by detecting highly feature rich parts of the map and using them as the centers of areas about which the tiles are grown around. Or alternatively explicitly using regional capitals to base the tiles around. Speed. This splitter is quite slow. It takes me 30 minutes to split the whole of Europe as defined by the Cloudmade extract, whereas it only takes 10 minutes to compile the generated files with mkgmap. A more even split. With this splitter tiles often have many fewer than the maximum number of nodes in a tile. For details of the splitter see the tile splitter page. [Less]

Today is the two year anniversary of the public announcement of mkgmap. It is interesting to look back and recall that the project started less than a month before that announcement. The map was basic and only included roads and only at one zoom ... [More] level, but it was still useful for mapping. I never imagined at that time, that two years later improvements would still be being made and there would be a separate web site and everything. [Less]

There has been a good response to the request to try out routing and lots of good feedback on the problems encountered. Robert has made a large number of fixes over the last few days and so I have put up an updated ready-built distribution on the ... [More] web-site. Updated links fixed Download as zip mkgmap-route-r806.zip Or, download as tar mkgmap-route-r806.zip I think this version is noticeably better than the previous one in many ways - give it a go! [Less]

Please help test out routing support in mkgmap by downloading one of the distributions below and testing it out. There are several known issues and routing support should be considered experimental at the moment, but we would like to get some early ... [More] feedback. In particular you need to be aware of the following issues: Only works with Polish format input files at the moment. Therefore you should get osm2mp to convert from .osm to .mp May not work well in MapSource, but if you have any success let us know, including the version number. Download as zip mkgmap-route-779.zip Or, download as tar mkgmap-route-779.zip Please give feedback to the mailing list at: mkgmap-dev (at) lists.mkgmap.org.uk or on the wiki on the routing talk page. For further information see the mkgmap routing page. [Less]

I've had word from Hanno Böck that there is a gentoo package for mkgmap. It's in the official gentoo tree, so it's just a matter of doing the following: ACCEPT_KEYWORDS="~x86" emerge mkgmap The link to the package page for mkgmap. There are a ... [More] number of other useful map related packages such as JOSM and mapnik that are used by OSM on the geosciences page too. [Less]

The subversion repository for mkgmap has been upgraded to 1.5 and at the same time it was moved to a different machine. You don't have to do anything and everything should look the same as it was, but I'm letting you all know just in case I've ... [More] forgotten to set something up properly. If you see that the latest version is 665 or above then you are seeing the new server. [Less]

There is now a Debian package for mkgmap, in "sid". Thanks to Andreas Putzo who made and uploaded the package and to the debian GIS team. Andreas also wrote the mkgmap man page which has been incorporated into the main mkgmap code base.

I stopped the nightly build that produces the mkgmap snapshots for a while as there are a number of changes being made that are large and not well tested. It has always been the case that the nightly snapshots are almost always perfectly usable and ... [More] quickly fixed if not. Usually they are better than the version that is marked as "stable". So they are disabled until this is likely to be true again after branches are merged back to the main trunk. Of course feel free to build from subversion if you want to experiment with the latest and greatest. [Less]

Just a quick note to say that in the not too distant future, mkgmap will require version 1.6 of java to run. Really the only reason why this is not the case at the moment is so that it can run with gcj. However it just doesn't really work with gcj ... [More] anyway as it either runs very slowly or goes into a never ending loop. If that were the only Free Software java then I would try to make it work, but Sun's version of Java is now available under the GPL licence and it works so much better for this application. So openJDK (also known as Iced Tea) is the only reliable way of running mkgmap and as this is 1.6 there is really nothing left preventing a switch to version 1.6. Having said all that, nothing will change until there is something added that actually requires 1.6, this is just advanced notice. [Less]