[JT] Jochen Topf's Blog
Thu 2019-03-07 16:29

The New Osmdata Service

For many year now I have been running a service at openstreetmapdata.com, first alone and then with the help of Christoph Hormann. We offered processed OSM data for download, most importantly coastline and Antarctic icesheet data. And although the service was always free to use and the software mostly Open Source, this was always our show. For a long time I wanted to change this and turn this into a proper OSM community project, and, finally, we have taken a big step towards that.

My application for some funding to the FOSSGIS e.V. (the German OSMF chapter) to pay for the servers was granted recently and the service is now online at its new home osmdata.openstreetmap.de. For the time being my old server is still running and the old address still works, but after some shakedown time for the new service, the old one will go away.

Technical background

The new service runs on the Hetzner Cloud. I have been using dedicated servers from Hetzner for many years and have been really happy with their prices and their service. For the first time I trying out their “cloud” services. While they don’t have as many bells and whistles as AWS or other cloud services, they have the essentials and they have very reasonable prices. Everything we need for this service.

The web site runs on their cheapest cloud server (less than 3 EUR/month) and that server also works as a “control server” that starts other servers as needed, currently once daily for doing the data update. When the data update is done after a few hours, the extra servers are shut down again, leaving only the control server running at all times. It is very easy to extend this to do more processing, maybe even in parallel where this make sense, on the type and size of servers that suit the need for each type of processing.

The web site and all the software controlling this service is available from this git repository. So, if you want to, you can run the whole thing yourself, or, even better, you can help us improve the service!

Information for users

If you are using the old service at openstreetmapdata.com, you should take action soon. If you are using the coastline or icesheet extracts, then download them from the new service and test them. While they should be mostly the same, we updated a lot of software and did some changes here and there, so we might have broken something. If it works for you, switch the download to the new server, if it doesn’t, tell us.

We are currently not offering the Generalized coastlines, the Reduced waterbodies as raster mask and the Reduced waterbodies as polygons on the new service. We might bring them to the new service, but this depends on whether people actually need these. Please contact me if you currently use any of them.

Why would I need this service?

If you have never heard of this before, you might be wondering why you would need this service at all. OSM data is sometimes rather complex and it is not always easy to work with it. When you are creating a map based on OSM data, you usually load the data into some kind of database and create the maps from there. But there are two special cases that are not handled by the usual software: The coastline and the Antarctic icesheet.

Almost every map has to handle the coastline somehow. You have to differentiate where there is water and where there is land. A special program reads OSM data and creates land or water polygons from it, that can be used to draw the land or water. You can run this yourself, or you can use this service to get current pre-processed data once a day.

Not quite as many people care about the rendering of the ice sheet in Antarctica. But if you want to render it correctly you have to take this special case into account: Usually if there is no land use or land cover mapped somewhere, a map will show some kind of generic land or water background color. But in Antarctica, the default color should be the one for “ice”. Because basically everything is ice down there, OSM doesn’t map the ice, but everything that is “not ice”. We offer prepared polygons and linestrings for download that take all that into account and you can simply include them into your map rendering process.

Both the coastline and icesheet data from our service is used for the main osm map and many other maps.

Wrapup

Thanks for FOSSGIS for paying for this service. And thanks to Christoph for all the work on it. If you have any questions on this, you can meet us at the FOSSGIS conference next week. See you there!

Tags: antarctica · openstreetmap · openstreetmapdata · osmcoastline · osmdata