Natureshadow's diary

Recent diary entries

Easily create OSM-based apps in Python with OSMAlchemy

Posted by Natureshadow on 22 September 2016 in English (English)

At the Python Unconference in Hamburg, we released the new OSMAlchemy library, which allows for the simple creation of arbitrary, OSM-data based applications with a low resource footprint in Python. It wraps around the popular SQLAlchemy database library and allows access to the whole world of OSM data as if it were in a local SQL database, and uses such a local database for caching.

See the GitHub repo for the code and a README, and find the original presentation from the release talk.

You can write to if you have questions or comments, or use the GitHub issue tracker.

Making OSM data mor compact

Posted by Natureshadow on 23 June 2013 in English (English)

Right now, I am trying to reduce data in the region I currently reside in. There is lots of different landuse around here, and the borders of these areas are often duplicated, so that there is approx. 1m of void between the areas. I have started to unite these borders by merging nodes, so that data load on mobile devices (that use OSM data rather than Mapnik tiles) is reduced and the map looks cleaner. After all, there is no such thing as void in the real world out there ...

Furthermore, what was mapped here is unlogical: In the real world, there is a track, and on the one side there is farmland and on the other side there is a meadow. What was done is: Create two areas for the landuse by drawing them on a Bing background, leaving approx. 1m of void in between, then draw the track by following GPS data. Now the way crosses the farmland, which, in the real world, it doesn't - it's right in between the two areas, so the areas and the way should share nodes.

I just killed more than 100 nodes by merging them in a logical way, while not loosing any map detail. Why was that map pollution necessary?

Location: Hof Waldeck, Ro├čbach, Hachenburg, Westerwaldkreis, Rhineland-Palatinate, 56271, Germany

Back to mapping thanks to Vespucci

Posted by Natureshadow on 18 June 2013 in English (English)


I started mapping again after I found the Vespucci editor for Android. With it, I can create and tag nodes and ways in the field, upload it as a draft and make some improvements and corrections back home with a "proper" editor.

Thanks, Vespucci devs!


Maps for limited groups of people

Posted by Natureshadow on 28 November 2008 in English (English)

I am jsut wondering whether trhere is a way of mapping elemenst only for certain groups of users.

For example, there may be areas that may only be passed by certain groups who are allowed there by their job or something.

It would be good to have a way of sort of "categorizing" map objects, for example there could be a field "limited_to" that the ncould contain something like "oxford_students".

When downloading maps, these areas could be enabled or disabled in some way.

Any ideas about that?


Mapping forest trails

Posted by Natureshadow on 17 July 2008 in English (English)

As I am an active geocacher, I am currently mapping forest trails (footways, bridleways) everywhere I go caching (mostly somewhere around my home). I think that is a useful improvement to the many roads that do already exist in OSM in this area.

I can't figure out why some mappers mark those way as "track", while it can easily be classified as "bridleway" or "footway" - not sure whether I should change that if I find clear hints on the official type of way ...


GPX Import failure

Posted by Natureshadow on 5 July 2008 in English (English)

My mailbox just showed up a mail reporting that my last (and first ;)) GPX file failed to import. I figured that the reason for this is that the timestamps are missing in the track log points.

However, my Garmin GPSmap 60CS **never** records timestamps - how can I upload a track then ??