kõik – drawing menu
The first short movie in the kõik on the MS Surface series; the drawing menu:
TileSeeder
Design for a python based GUI program for tile management.
(Image taken from the presentation I’m giving at foss4g 2010)
Visualizing OpenStreetMap history – part 2
Thanks to the hard work of Vincent we now have a database with the average version and average age of nodes per grid cell. Now we can start to get a feeling of the data. I’ve rendered both datasets for Amsterdam on a 10x10m grid. In general the idea is that red is bad and green is good. The younger a node is, the more likely it reflects the current situation in the real world. Also the higher the version number, the more people have been looking at that node and corrected it.
At least that is the theory Martijn tries to work with.
The age in days for OpenStreetMap nodes
Visualizing OpenStreetMap history
I’m working with Martijn and Vincent on a way to visualize the history of OpenStreetmap data for their analysis of the ‘crowd-quality’ of the data. I used my favorite visualization tool Processing to visualize the history of one node:
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.
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.
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.
Is it better to burn out, or to fade away?
Last week we, the Mapbuilder PSC, have decided to gracefully terminate Mapbuilder. We found that other webmapping projects (notably OpenLayers) had passed us in userbase, developbase and finally also in features. We decided that the answer of the ageold question is to burn out. We’ve sent out an announcement that we have reached the end of life of Mapbuilder. It is a sad day…
Dark skies are looming over me
But in general I think this is a good thing and OpenLayers will grow even faster, it is a great package after all.
Tilecache seeding for .nl in 900913
For the new EduGIS webmapping client we are using mapbuilder 1.5, openlayers 2.6 and TileCache 2.0.1. We have around 30 layers containing data for the Netherlands. To seed the tilecache for these layers takes quite some time, especially if you do not give the proper bounding box.
Tilecache_seed.py, the simple seeding client that comes with TileCache, takes the following parameters:
tilecache_seed.py <url> <layer> [<zoom start> <zoom stop> [<bbox>]]
The url parameter apparently doesn’t matter, it just uses local python. The layer is the layer you want to seed. Optionally you can limit the number of zoomlevels which you want to tile and the bbox of the area to be tiled. If you leave these out it will default to the entire world and all zoomlevels.
For .nl in google-projection I’ve used these parameters:
python.exe tilecache_seed.py "http://url.to.tilecache/TileCache.py?" layer 1 18 "350988,6571138,827965,7133714"
This will generate 2870400 tiles on zoomlevel 18 and it takes some time (think days). It is probably more useful to seed until level 17 or maybe even 16 and tile everything else on the fly.
OSGeo conference in .nl
Yesterday was the dutch (mini) conference on open source geospatial software, organized by osgeo.nl. I was too late to join the technical workshops, but the talks turned out to be fun as well. The different talks mainly showed of projects which somehow worked with open source. The most interesting talk for me was probably the one by Dirk Frigne of DFC. He showed of Majas, a new application they have been developing for the past two years. Majas is a browser based vector editor (amongst others) which supports snapping etc. They started developing it before OpenLayers existed and are now considering to write OpenLayers into Majas as their map renderer.
Apart from having good vector editing capabilities it has a nice architecture which resembles Mapbuilders MVC. From what I’ve seen it has the potential to become a widget framework around OpenLayers, what Mapbuilder tried to become and mapfish is currently trying. In Capetown they will talk further on integrating with OpenLayers, so to be continued.
There was an interesting discussion on what it meant to ‘do’ open source. Just using it was found to be not enough, you need to contribute your code and preferably also make the source code of your project available. The discussion went on for a while on whether or not we needed more legislation to force open source into the public sector. (Bad idea IMHO) At the end there was a smart remark on the sorry state of OSS, we are needing/using legislation to get people to use open source software. The guy stated that we needed to work on our marketing, so people want to use it, I totally agree on that!