I have found a new subject to scratch my head: i’m trying to work with OSM XML files (geographic data used to draw map). I made a program to convert the file into an sqlite database (nodes, ways, relations). The latitude-longitude values are converted in planar coordinates (to draw on screen) with a Lambert azimuthal projection.
MVD is very efficient for this. A lot of SQL statements are required which consume a lot of time. I choose to put the sql file on a RAMdisk. Even if the RAMDisk is 200X more faster than my hard drive, the import of the XML file (a big one) take near 10 minutes. Fortunately, the import is only required one time.
Now, I’m able to draw streets and houses. It was a very interesting thing to explore. I have a lot to optimize and maybe some bugs to catch. I’m not sure I will release an application, more surely some tricks how to process.
Now, I would like to implement some aspect of the graph theory but that is another story 😉
Lambert azimuthal equal-area projection
Show a part of an opentreetmap.org export