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.

To be able to show nicely (as in not an XML file) that everything worked I was asked to build a webclient which would show a map and the data from the EGN service for that area. I figured that this was once again a good reason to look into the latest developments for OpenLayers. I quickly discovered that the released version (2.7) doesn’t support WFS 1.1.0 so I asked on the mailinglist if people already tried to implement it (and if not, pointers how to do so). Luckily people already did the work and created various patches for the support. (thanks tschaub, bartvde and others)

The most important patch is the one which implements protocols for WFS: ticket 1648 and its wfs.patch The main disadvantage of this patch was in my case that it tried to minimise the number of requests to the WFS server (which in general is a good thing). It requests all the features which are within twice the size of the viewport and it doesn’t request new features when you zoom in. However our server is limited to 10 features per request this results in very interesting behavior. For a starter all the 10 feature could be outside your viewport and also very funny is that shown feature might dissappear when you move the page too much (it requests new features in that case and the first 10 might be outside the viewport). A second patch, on ticket 1830, provided a more aggressive feature update: each zoom action triggers a new request and I set the request-boundingbox-ratio to 1, meaning only those feature within the viewport are requested. This means that every action triggers a new request, which is heavy on the server.

However this is just a reference implementation and hopefully for actual implementations they remove the 10 feature limit. For those interested the reference implementation can be found at http://research.geodan.nl/egn

Finally it has arrived the ‘The Internet‘

I was curious what kind of feedback you get from the Wii-mote and where it fails (in light of the news about the Wii motion plus). There are some issues around getting your Wii-mote connected to a PC by bluetooth, not every stack is good, nor areall bluetooth chipsets, however the MacBook supports the Wii-mote out of the box. So I connected the Wii-mote to my MacBook instead and used the DarwiinRemote application to get a reading from the sensors.

DarwiinRemote sensor readings.

The wii-mote is equiped with an accelerometer, which does not record the position of the wii-mote. What is does is that it records the different forces (accelerations) that are applied to the controller. So in rest it will record a force of 1G down (z= -1). If you hold the controller upside down it will record a force of 1G up (z = 1) (seen from the point of view of the controller). If you hold it on its side the reading will be x=1 or x=-1 or y=1 or y= -1, depending on the side. The other axis will be 0 in rest. Actually since in rest the only force acting on the controller is earth gravitation, which is 1, the absolute sum of the forces on x, y and z will be 1.

Wii sensor reading in three orientations.

With this knowledge you can deduce the orientation of the Wii-mote from the readings above. In the beginning the Wii-mote is held horizontal pointing forward (blue line at -1). Then the Wii-mote is rotated along its body, the left side is pointing up (red line at 1). Finally the Wii-mote is pointing downward (green line at 1). Note that we do not know how the Wii-mote is pointing downwards (whether the buttons facing forward or sideways). When you start moving the Wii-mote the forces applied on the Wii-mote easily surpass the 1G and when that happens it is much more difficult to deduce the orientation. The new Wii-motion Plus extension is supposed to solve this problem. From what I’ve seen and read it most likely will use a gyroscope to calculate the orientation of the Wii-mote regardless of the forces applied to it.

Obviously since there are a tens of thousands cyclists in Amsterdam, so injuries are bound to happen, even deadly ones. I’m not sure of the statistics involved: whether everyone buying and wearing a helmet would have a big impact in the total population of cyclists. However if one ignores statistics I’d argue for compulsory shin-protection as well.

As it happens, this morning I was cycling to my work, managing all the busy intersections with trams, trucks, road construction etc without any incident. Just before I arrived at the office, I cycled through a quiet little street, here, where a van was parked in the middle of the street. To avoid the van I had to squeeze my self between the van and the underground garbage containers at the sidewalk. However one of those was mysteriously not totally underground leaving a sharp metal plate at shin level. It happened to be able to slice both through my pants and my leg. Resulting in this very nice gap in my shin (gore-warning!). Right now I’ve got 7 stitches and am pretty much immobilized by a non-functioning right leg

I like the new focus on security; I’m waiting for the moment that it will warn the user when booting Windows: ‘Warning: Turning on your computer might allow the execution of malicious software ….’

I love Eastern!

Since one of the reasons to buy a macbook was to try Mac OS X I’ve postponed the ubuntu install and work solely on OS X. I’ve to say as an ubuntu junky and windows drone, it’s a bit tough to get used to it. I miss the total control of linux (full cli amongst others) and the keyboard navigation of windows/linux. The bright side is; it is absolutely stunning (as long as it works) the nifty animations, front row and iSight don’t fail to amaze my fellow workers.

So after my first 48 hours of OS X I’d advise a intelMac to anyone who likes to play around: it looks funky, it works (most of the time) and you can always destroy everything and install windows

Note the just bit; there are no backups of all the tweaks, most of them we still know, so it should be possible to recreate them in a few days, but due to holidays it might take several weeks before we have it up and running again and syncing with the other server. So we’ve adapted DNS to point www.edugis.nl to the old server again, which is qutie fast as well, but just not as fast as the other :’(

IE7 however is a much smarter browser, so I liked to test it there as well. Apparently, however, IE7 is too smart for its own good. It doesn’t want to show me a webpage. For the record, the (virtual) computer was connected and I could access the site with another browser.
Maybe it has a build in filter that knows which pages are dangerous to the user, since FF did work on the same computer and showed non-dangerous sites without a problem.