TileSeeder
Design for a python based GUI program for tile management.
(Image taken from the presentation I’m giving at foss4g 2010)
Creating a timelapse movie with ubuntu
It has been a while since I made my last timelapse movie and I figured that today was a good day to check the status of linux and timelapsing. A quick google gave me gTimelapse which should allow my to use my dSLR as a timelapse camera. This would give me two advantages over my old set-up (and one disadvantage). My old set-up was a Nikon S4 with a power adapter and a reasonably big SD card. Having a power adapter meant that I could leave it running for months, which gave me for instance:
Visualizing gps tracks with Processing
At work we got an i-gotU (a GPS logger) as a Christmas present. To show what one can do with it I decided to ask a few people to use their i-gotU to record their travels for two weeks. This resulted in over 42000 locations done by 8 different persons. Each person got his/her own color in the visualization to be able to see when people were near one another. Since the office is in Amsterdam and most people live in (different parts of) Amsterdam you can quickly see the contours of Amsterdam’s city-plan appear. Also interestingly is to note that people have their own specific areas where they spend most of their time.
Perceived WCS inaccuracy
Working with WCS I discovered a small but noticable shift of data in all three major OSS WCS applications:
- Geoserver 2.0 (SNAPSHOT downloaded 8 december 10.19UTC)
- Mapserver 5.6.0 (MS4W Base installer v3.0 Beta 7 + MapServer 5.6.0 release Upgrade)
- Deegree 2.3rc1 (Apache Tomcat 5.5.28)
To find out what the problem exactly was I’ve done some testing. I’ve taken a GeoTiff and configured all three the WCS applications to serve it. Gdalinfo gives us the following information, basically it is a GeoTIFF in epsg:3035 with a native resolution of 100m/pixel.
WFS 1.1.0, GML 3.1.1 and OpenLayers
In the INSPIRE framework we are working on the ESDIN project and are using the EuroGeoNames (EGN) project as an implementation of ESDIN. INSPIRE is a big thing within the GIS world in Europe and loads of documents have been written so far.
We’re involved in both ESDIN and EGN and we decided to use the latter as a trial for the first. Together with our partners we’ve setup a series of servers to fulfill the needs of the projects. The main standard used is the latest WFS and GML versions, which have the annoying disadvantage that there are few clients available.
State of the Map
My friend and colleague New Folder is organizing the State of the Map conference this year. He asked me to design a banner for the official site. The conference is, apart from the usual OSM gathering, also focusing on businesses/governments and how they can use OSM data in their line of work. So I decided to create a banner which reflects the transistion OSM has been through. It started with a single idea and a few people collecting GPS tracks. Slowly from these tracks roads could be destinguished. Different types of roads where classified and more and more data was included and suddenly you got a map which at some points was more detailed than a ‘commercial’ map.
First draft SoftM'09 banner
OSGeo dances the Tango
I finally did the right thing and emailed OSGeo that I’ve stopped coding and would like to use my designer skills instead. I was pointed to this wiki which pointed me to the site of Robert Szczepanek. He had created an entire iconset for QGIS inspired by the tango rules. I contacted him and he was very much interested to extend his work for a broader iconset for the OSGeo community. So where I expected to start from scratch I’m kickstarted to the point that I have to think of secondlevel issues like hosting, naming-schemes etc.
Still I’m very much excited by the prospect of creating beautiful GIS applications and so far I’ve had enthousiast reactions from developers as well.
TileCache in the cloud
Since cloud is the buzzword of the month I decided to have a look at TileCache‘s support for Amazons cloud storage S3. Since TileCache version 2 the whole architecture is much more modular. It is easy to write new backends for different kind of caches. One of those backends is AWSS3 (Amazons S3 storage service).
For EduGIS we figured that it might be easier and more scalable to serve all tiles from S3, using the bandwidth and storage space of amazon, instead of buying more servers and bandwidth ourselves. Already we use tilecache in a test setup and the initial idea was to replace the diskcache for an AWSS3 cache. This was we could tap into the vast storage space of amazon, however, since every request had to be forwarded to S3 and back, the bandwidth-load was doubled. So instead of hosting the TileCache on our server we moved the TileCache instance to a virtual computer on Amazons EC2 platform.
To do this, I picked a sample machine-image of a small, headless, ubuntu 8.10 setup. Installed tilecache (apt-get install tilecache 
) and changed it to use mod_python instead of the default cgi in apache. Since this means that the machine-image is changed, you need to bundle it into a new machine image and register it with amazon. this way you can easily create multiple instances, also if you powerdown your machine it gets destroyed so you loose all your changes.
So once I mastered the art of cloud-herding I pointed our test environment to TileCache in the cloud to see if it would work at all and how quick the bill would increase. After a few days and some seedings I noticed that the AWSS3 backend uses a simple dump in a single folder backend. This quickly produces insane amounts of files and it becomes impossible to have a quick look at the status of your cache with tools like S3fox. So I wrote a patch for the AWSS3 cache module to store the tiles in a TMS style folder structure.
Now all we need to do is to create a tilecache.cfg with all 200+ layers we have and start seeding.
Cape Town day2
My lightning talk yesterday went pretty well, there is a flickr photo of me stating “Steven gave a great lightning talk obituary for MapBuilder at the Plenary session.” There was a wonderful talk by Schuyler, which fortunately is videotaped, but due to the insane slow internet I haven’t seen yet. Also fun was the talk by Ed Parsons from google. He talked (amongst others) about Map Maker and a fairly though discussion resulted about OSM, map maker and data sharing. The interesting bit is that they’re not against sharing their data, it is just that they don’t have a proper license to do so (nor does OSM for that matter). It will be interesting to see what is going to happen in this space. Apparently the lawyers think that it is all public domain and don’t fancy writing a proper CC/FOSS-style license for geodatasets. They state that geodata are facts and facts are not copyrightable.
Unfortunately today was slightly less successful, apparently quite some presenters couldn’t make it after all and three of the talks I was looking forward to weren’t there. SO hopefully the BOF on openlayers and extjs will be better. Interesting projects to look into at home so far are: QGIS-mapserver and Mapfaces.
netatalk and os x playing up
I’ve spent my entire evening fixing my appletalk set up after I accidentally ‘upgraded’ my handcrafted netatalk with the stock ubuntu one. I crafted my own because the stock package doesn’t support encrypted passwords.
I’ve reinstalled, rebuild and rebooted netatalk on the server and I kept getting this error:
“The operation cannot be completed because one or more required items cannot be found. (Error code -35)”
Googling this error didn’t give me much and it took me a while to realize that googling for: error code -35 will give you no useful results do to the minus sign. In the end I discovered that it is not ubuntu but Apple to blame for the error. Apparently at some point in time the globalpreferences get fcked. So the solution is:
rm ~/Library/Preferences/.GlobalPreferences.plist