August 5th, 2008
I’ve been a geek for awhile now, but I knew I had taken it to another level when I realized I was excited about the data coming off Jason-2, the new NASA-CNES (French space agency Centre National d’Études Spatiales) oceanography satellite. In this article, Michael Freilich says,
“Precision measurements from this mission will improve our knowledge of global and regional sea-level changes and enable more accurate weather, ocean and climate forecasts.”
I expect data collection efforts like this to be available through GEOSS in the near future, so the question is, where are the WCS and WMS services?
Get more details here:
Tags: climate, wcs, wms
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July 22nd, 2008
I was at the Earth Science Information Partners (ESIP) meeting last week, and was a little surprised at how much these folks like KML and GeoRSS. OGC stalwarts generally think of simple encodings like these as just good enough to get the job done, if the job you’re doing is pretty simple. The jobs of ESIP members is not, however, simple.
This group is comprised of NASA researchers and other earth, air and water scientists who regularly deal with multi-terabyte databases of satellite imagery and other GIS data sets, so you’d imagine that they would be quite content with their high-end GIS systems. But while there was certainly plenty of industrial strength GIS going on, a good third of the attendees came to the KML and GeoRSS Birds of a Feather session. This made me realize two things:
- The work we did in OWS-5 on defining how to output KML from a WFS will be very useful
- We’d better tell people about it so they don’t duplicate our efforts
So at this point you’re probably saying, “get to the point. How do you output KML from WFS?” The easy way is to just get software that does it. In OWS-5, the open source Geoserver and Galdos Systems’ commercial product Cartelinea implemented this functionality. If you have your data in PostGIS, ArcSDE, Oracle Spatial, or Shapefiles, just set up the Geoserver or Cartelinea to server that data via the WFS API and you get KML support for output automagically.
If you want to know how to code your own support, you’ll need to read the upcoming revision to the “Styled Layer Descriptor profile of the Web Map Service Implementation Specification”, but I’ll give you the 30-second version here.
A WFS outputs only data (usually in GML format). KML, however, is data plus styling rules. So to control the output of KML from a WFS, you specify the data you want with a normal WFS request, but you also specify the styling rules using the Styled Layer Descriptor (SLD) language. We call this combination of data request API and style configuration a Feature Portrayal Service (FPS). It’s pretty much a melding of the WFS and WMS APIs. So if you’re familiar with WMS, WFS, and SLD, implementing FPS is straightforward. Just read that SLD profile of WMS document and let me know how it goes.
Tags: fps, galdos, geoserver, kml, sld, topp, wfs, wms
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April 15th, 2008
After a little less than a year of great work by the KML SWG, we have a standard! The OGC press release gives some facts and a link to the OGC KML 2.2 Standard, and John Timmer at ars technica has a nice piece on the significance of this step. His article won’t offer anything new for geo industry veterans, but it’s great to see the mainstream IT media “get it” when it comes to our technologies and markets.
This is hopefully a big win for individuals who contribute data to one site, and would like to use it in many others — not to mention the companies whose business model revolves around these altruistic, bottom-up data providers. One small step for OGC, and one big step towards breaking down data silos!
Tags: kml, ogckml
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March 27th, 2008
This morning at the OGC Technical Committee meeting, the Google Earth & Maps team announced an alpha of libkml, an open source (BSD) library for reading/parsing/writing KML 2.2. It’s a C++ library, but includes SWIG bindings for Java, Python, Ruby, Perl and PHP. The hope is that this piece of code will help developers build comprehensive, robust KML support into their applications. But note, this is NOT a mini-Google Earth. You just get KML support – there’s no way to get that streaming earth imagery goodness that you see in GE, although I suppose you can combine this with a map access API (from Google, Virtual Earth, Yahoo!, etc.) to get nice base maps in your app. Enjoy!
Tags: kml, mass market, ogckml
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February 25th, 2008
Needless to say, I was shocked and amazed when I saw this statement on Microsoft’s new Interoperability Principles this weekend. To summarize, they are committing to make open and public the protocols and APIs for their major products, including Vista, Exchange, SQL Server, and Office. And, wait for this, access to those documents will be free. Is your mind blown yet? How about reading on and seeing that they plan to embrace non-Microsoft standards, and “increase interoperability with open source solutions”? I’m going to take all this at face value and say, “Bravo Microsoft!” I hope it all plays out according to this plan. The IT world will be a much better place if it does.
Tags: mass market, microsoft, standards
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