Archive for the ‘Open Standards’ Category

Geo Mindstorms

Friday, September 12th, 2008

I’ve recently purchased a Lego Mindstorms NXT. Of course for my sons, but as they are a bit too young for it now, I will have to use it.

It’s also for my work actually. The Lego Mindstorms is an affordable tool for different subjects we are researching, such as:

  • OGC Sensor Enabled Web
  • Location based services
  • Command & control
  • Automonous behaviour

OGC Sensor Enabled Web
The OGC Sensor Web Enablement is quite obvious: The Lego Mindstorms supports different sensors. Standard e.g. a light sensor, measuring light intenstities, and a sound sensor measuring Db and Dba. You can also buy additional sensors like temperature, RFID and gyrometer sensors. The sensors can be used for the different components of the OGC SWE. The first components which will probably be used are:

  • Observation and measurement (O&M) to encode the sensor data
  • Sensor Model Language (SensorML) to describe the sensor systems
  • Sensor Observation Service to request, filter and retrieve sensor data.

Later the planning and alert services could be added.

Location based services
Also location based services are quite obvious. The built robot has a location and thus could respond to it (e.g navigate, react on POI’s, etc), or other applications could react to the location of the robot. Of course we first want to show the location of the robot on the Touchtable.

Control & command
On above mentioned touchtable the user could give commands to the robot. Eg to move to another location, to send measurements etc. The robot could act as a mobile field user who receives commands from a control center. Because a PC, like a UMPC can be attached to it, it could mimic the behaviour of field user ,like measurements teams during a disaster, in a training situation.

Autonomous behaviour
Contrary to the C&C mentioned above, you can give the robot an order (e.g. to move somewhere and drop something). Also the robot has the abilities to respond to situations itself. These kind of autonomous behaviour is for example examined in disaster management but normally requires an expensive system.

Conclusions
The Lego Mindstorms is an very affordable tool to investigate different geo related subjects in a extremly easy (and cool) way. It has the potential due to its combination of sensors and intelligence to investigate even further and implement trully geo-innovative ideas for only minimal costs.

WFSHarvester on SourceForge

Friday, May 23rd, 2008

The WFSHarvester is now an Open Source project on SourceForge.
Project website: http://wfsharvester.sourceforge.net
SourceForge site: http://sourceforge.net/projects/wfsharvester

There is not a lot to find though. At this moment I am adding comments to the source files, cleaning up some stuff, writing a few lines of documentation. When this is done I will put it in the SourceForge.

After that I will create some sample files and a simple client for testing.

WFS Harvester to go Open Source

Thursday, May 22nd, 2008

Because the WFS Harvester is so simple and might be useful for other organisations as well I’ve decided to create an Open Source project. Apart from making the harvester available to other people, I also hope someone might improve it :)

WFS Harvester

Thursday, May 22nd, 2008

For a project it is necessary to harvest data from several distributed WFS’s and put the data in a central WFS. A simple and configurable WFS Harvester is developed to perform this task. Because a few easy to configure configuration files are used it can be used relatively easy for different WFS’s.

The WFS Harvester requires 4 parameters:
1. XML file
2. URL of WFS
3. URL of WFS-T (Transactional WFS)
4. XSL file

The XML file contains a GetFeature request. This request is sent to a WFS. The XML result of this request is transformed into a Transaction request using the XSL file. This transaction request is then sent to the WFS-T.

Of course it could be improved by requesting for the capabilities of a WFS and so on, but now it’s an easy simple library. The XSL file allows for example to copy WFS data from one datamodel into different datamodel and store it in another WFS.

Snowflake Software GML Viewer

Friday, March 14th, 2008

Today I came across the GML Viewer of Snowflake Software. It promises to display any GML2 and GML3 file. After testing several GML viewers I was a bit sceptical about that. However it really did open any GML 3 file I tried! Really great! I have not used it very extensive yet, but a few random GML documents I retrieved from my Deegree setup for GDI4DM were indeed visualised without problems.

There are some minor points as well, the user interface could be more friendlier and usable. Also the WFS 1.1 request didn’t work for me.

In the end it seems a nice additional tool to easily visualise GMLs without much problems.

Actually I am a bit sad as it does almost the same as I was planning to do. I was about to write a GML viewer in .NET/WPF capable of displaying any GML3 file as well by just parsing any GML without validation and simply walking through the structure and displaying any found GML geometries and their sibling elements. Well I’ll still do that, just for fun at home to play around with WPF/C# and make it open source.

Turning OpenStreetMap into a WFS

Saturday, March 8th, 2008

Yesterday I worked with my colleague Martijn on making openstreetmap data available through a WFS. First he put the data in a PostGIS database (see the post on his blog). After that it was quite easy to make the data available in Deegree WFS.

It appeared the import tool om OSM did not add primary keys, so they were made by adding a serial type column to all OSM tables and making it the primary key.

After running a java tool to create the Deegree WFS datastore XML for OSM and adding some lines to make the OSM features visible and queryable the Deegree WFS was up and running.

So now we have a WFS 1.1 service supplying OSM data in GML 3.1.1 format.

Nice result in a few hours, but I still want to do some things, namely:
- Change the default app namespace into an osm namespace. Actually this is done in 5 seconds…
- Try to output GML SF. The OSM tables are very simple and flat, so SF should be more than enough.

Dutch Government – List of Open Standards

Thursday, March 6th, 2008

In 2007 the state secretary (deputy minister) Heemskerk launched an actionplan to improve interoperability between and inside governmental organisations using Open Standards and Open Source.

On march 3th the first action was presented: a first version of a list containing the open standards Dutch government organisations should use or support. The list can be downloaded here: http://www.forumstandaardisatie.nl/fileadmin/OVOS/Basislijst_OS1.pdf

Apart from several national standards some of the choices are:

  • Support of ODF
  • Usage of PNG for lossless compression
  • Usage of JPEG for lossy compression
  • ebMS and/or WUS

Regarding GDI it is proposed to use the “Framework van standaarden voor de Nederlandse GII”, version 2.0 as defined by Geonovum.