January 26 2006, Emmen (the Netherlands)
Most of you will probably be aware of the previous GML relays. On January 26 2006 in Emmen (the Netherlands) the fourth GML relay is organized by Geo-Information Netherlands (GIN). For the first time in the relay history GML 3.1.1 will be used (as supported by both OGC and ISO TC211). Again, a topographic data set will be used, but this time it is not a prototype anymore, but the actual TOP10NL production version. Also different from previous relays is that it will be a whole day event. This gives time to validate every written GML document (by the organization) before passing it on to the next participant. The concept of the relay remains very straightforward, each participant:
- reads GML data into the system;
- edits this data (add or modify a few features);
- saves the edited data for the next participant.
For the 4th GML Relay the following procedure will be followed:
1. Someone from the audience will draw (live) the order of the relay. This will make the order random
and prove that the relay is not a fake. If there is sufficient time, the first participant should also read
the result of the last participant.
2. The whole GML document is read/written according to the structure defined in the TOP10NL
application schema and one object is edited (both geometry and attributes).
3. Everybody brings his own laptop with software, and exchange of the data will be via an USB memory
stick. Every time a new name (or directory) will be used (with the name of the participant and
number in the relay); e.g. relay_esri_1.gml.
4. After saving a GML document, the organization will check if the written document is indeed GML via
a validation tool (and check this against the schema of the TOP10NL).
5. In case of errors, there is no discussion, but we will go back to the previous valid GML document
(after the event the error will be solved and the exported GML will be put on the website
www.gdmc.nl/relay together with all the other exported files).
6. Participants should practice in advance by off-line testing. At least 3 weeks in advance (but the
earlier the better) an edited and written sample should be made available by each participant via
7. Every participant gets the same amount of time for the GML relay: 15 minutes (an additional 10
minutes may be used to explain GML related developments).
Geo-Information Netherlands (GIN and one of its predecessors, the Netherlands Society for Earth Observation and Geo-Informatics; KvAG) organized the first three GML relays (respectively June 2001 in Wageningen, December 2002 in Emmen, and November 2004 in Delft). Purpose of these events was to show that interoperability between different software products based on the exchange of GML documents does really function (also in a non-lab or test-bed environment). This did indeed work with more or less success during the previous relays and the goal of the final, 4th relay is now to show the progress in implementations via the use of the production version of the TOP10NL in GML 3.