Many people have asked me about software that supports GML 3.2. This version of GML is pretty new, but it’s probably the most important version of GML since it’s the one that has become the ISO standard for geographic encoding in XML. Recently I got at email from the folks at The Carbon Project, announcing GML 3.2 support in their free geographic data viewer, Gaia 3.3. Check it out. Lots of documentation, even in video format. Gaia is slick, stable and has a ton of features built on OGC standards.

In the OGC Mass Market Geo Working Group meeting yesterday, I presented the preliminary findings of the group brainstorming about the future of KML in the OWS-5 testbed. Most of what was discussed isn’t ready for prime time, so I’ll wait to talk about for a few months, but one critical point that everyone should understand is that KML is, always has been, and will continue to be about mapping/geospatial visualization. Don’t use KML as a data storage or archival format. That’s what GML is for. Yes, KML has some geographic coordinates in there, but KML’s ability to act like a GIS format–attaching other data properties to the geography, typing them, and putting metadata on it all–is weak.

The right way to think about the geographic information “workflow” is to have a spatial database that serves up data to the Web via the Web Feature Service (WFS) API in some flavor of GML. Soon, OGC will specify how that WFS should serve up KML using the existing WFS API plus some extra information to describe the transformation–probably using SLD. The authoritative data will still reside in the spatial database. The KML will just represent one cartographic view of the data at a particular point in time.

See my post on the GeoRSS blog. Hope someone can help out.

In the OGC meetings last week WFS Simple was presented to the membership as a part of the “OWS4 GeoDSS Mass Market (formerly GeoRSS) IPR” (note this link will only work for OGC members for a few more days). It was approved as a discussion paper, which is a document that’s worth making public, but is not necessarily an “official” position of the OGC (as a Best Practices paper is).

There were two major areas of discussion at the meeting. One was around whether WFS Simple should harmonize with WFS and become the most basic WFS implementation. The other was related to Basic XML Feature Schema (BXFS) as the default output schema for WFS Simple. These are actually related items as the biggest problem with rolling WFS Simple into WFS would be the issue of having GML as a required output format.

Although at first blush it sounds nice to bring this work into an existing service, I agree with the opinions that it should stay separate. GML as a required output format is too important of a foundation of WFS to tinker with. Therefore I propose maintaining the separation and pursuing the following work items leading to a 1.0 specification.

1. keep WFS Simple focussed on being the generic geospatial data query language for mainstream web data formats like Atom+GeoRSS, KML, etc.

2. Componentize the design of the service, so that this is not really one service, but a simple, clear way to design services focussed on a particular data type like Atom+GeoRSS by adding or removing a parameter or two.

3. Re-emphasize the separation from WFS by moving towards a 1.0 specification with a new name, Geodata Query Service

The big news of the week was Microsoft Virtual Earth’s announcement of a new version of Live Maps, and Google following days later with a new feature called My Maps. These are both ways, put simply, to do heads-up digitizing in a Web browser!
The importance of this is development is hard to exaggerate. For years the consumer marketplace has done street mapping extremely well. But that was just streets. “Real” GIS folks need to overlay data from various sources, right? Then last year OpenLayers let you have the best of both worlds, overlaying any arbitrary WMS on top of a Google Maps base map. With the merger of OpenLayers and Community Mapbuilder, expect to soon see a Google Maps base map under your choice of WMS and WFS services and/or embedded GML data, styled with SLD and all wrapped up in a nice KML or Context document.
Add to this the ability to create geographic content in your Web browser and access it via a URL, and a very interesting vision of Web-based GIS begins to emerge. It’s a vision that’s very different from the one the GIS conference circuit has been giving us all decade. I could expound on what I think that vision is, but that’s not really important. The most interesting thing I see here is that the architecture is so beautifully loosely-coupled that there is room for everyone’s vision to be realized. One thing I will predict is that the truly interesting time for Geo-startups begins now.

p.s. Does anyone else find it odd that such a major new feature was introduced by two pretty big companies in the same week? Coincidence, or something else? Please Adena get some dirt on this! inaccurate statement, see comments –Raj