Process

Digital Earth Weblog on WMS integration

Andrew Hallam at Digital Earth Weblog writes his third installment in a detailed series on Google Earth. This time he posts on getting WMS servers to show up in Google Earth, and homes in on those places where both Google Earth and WMS protocols have room for improvement.

Some notes on his notes, then:

1. Finding a WMS: One place to look is Mapdex (no surprises there). Do a search for “WMS” in Service and you’ll get 394 services from 109 servers. That’s a good start for experimenting.

2. WMS Reflector Script: I like the “reflector script” (great name) that Andrew uses, as it is quite versatile and robust, certainly more so than the one I used when experimenting on Canada, in this post.

He notes of the script that he uses, however, that “the big limitation with this approach is that the user has no control over what gets displayed. They cannot turn the individual WMS layers on or off.” He proceeds to try to work around this limitation by constructing a KML document that contains multiple network links, all containing one layer. The end result is understandably a bit clunky looking.

Unless I’m mistaken, however, and perhaps Andrew has already considered this route but dismissed it for reasons I haven’t figured out, there is a conceptually simpler way to construct the reflector script, involving multiple <GroundOverlay> elements inside one folder (which is allowed), each of which holds an individual layer that can be turned on or off separately. This is what I did for the Canada reflector script [txt], and it means you only need one network link, and it can be at the top layer in your Places. (The full post, with KMZ network link)

As for HTML legends — these are nice, but if you’re not so wedded to it having to be HTML, then you’ve already done most of the work if you make a PNG out of it, and then display that as a ScreenOverlay. Here is an example using Andrew’s PNG [KMZ]. All we need then is a web service that turns HTML into a PNG and returns it, and we’ll suddenly have a nice pipeline for generating floating legends for Google Earth. Of course, there are no links this way, but you could keep those in the descriptions in the Places window.

7. The XSL Stylesheet is extremely cool, and it is exactly what WMS needs for automated delivery to Google Earth. Jeremy at Mapdex, is that something you could use to generate a network links with component &lt:GroundOverlay> tags for layers, much like you did with ArcIMS?

Uncategorized

Katrina Catch-up

Although this blog sometimes succumbs to mission creep, I usually try to keep it on target: Documenting new and innovative uses of Google Earth, as well as the social issues raised by the sudden democratization of GIS tools.

I didn’t blog weather map overlays of Katrina, as that is now a pretty mainstream use of Google Earth, and the obvious place to look for these resources is on Google Earth Community and Google Earth Hacks (I try to avoid me-too blogging). Then I was at a work retreat for a few days, only to find Katrina had turned into a category 5 story in the meantime.

The images from the ground in New Orleans are truly moving. Is there anything worth reporting from the periphery, from the perspective of a Google Earth-centric blog?

Yes, two things: First, Google Earth and its imaging provider Digital Globe, are intent on providing a much accelerated response time for image updates when it comes to mapping significant natural (and man-made) disaster news stories. If this continues, this will turn Google Earth into a much more useful real-time tool than the reference work it amounts to currently.

Second, many news organizations added their own overlays in Google Earth and used them prominently on screen — CNN in particular. The best way to grasp the extent of environmental disasters like Katrina is Google Earth, and now many more people know it.

[Update 2005-09-02: Google has a page up with overlays for Google Earth.]

Opinion

Onwards to Russia

2 Comments

Mosnews sometimes has stories of dubious quality, so it is by no means clear in this story whether their “source” speaks for the Russian Special Services, but he’s quoted as saying that with Google Earth “terrorists will see all that they need to carry out an attack in any part of the world.”

If the source is real, what scares me then is that the Russian Special Services are complaining due to ignorance of a fact that any intelligence service should know: These images have been readily available for ages. Either that, or they just hate openness. Or both.

Opinion

Privacy luddism

3 Comments

Whenever somebody begins a rant with “Who gave X the right to…” I reach for my polemical guns. In this particular case, Sean Copeland at EarthHack.net begins badly by asking, “Who gave Google the right to web publish photographs of my backyard so detailed that I can see the details of my landscaping?” He’s “working on a legislative and lobbying strategy to drive action in Washington on this assault on our privacy.”

Does he really not know? The answer is: Because the technology and the imagery is available; because information wants to be free; because it is more equitable to have unfettered access to such information than to have access determined by the ability to pay or governmental fiat; because I’ll buy the high-resolution image of your backyard from a French company and overlay it on Google Earth and publish this to a German forum if I want; because somebody else will provide access to a server that does this for any region, from outside any jurisdiction you care to name, using any arbitrary web platform; because nobody cares about your landscaping, except for the people who do, who will find a way to see it; because the circumvention of whatever measures you propose will cost less in time and effort than the measures you propose.

Matt McIntosh calls Copeland’s stance privacy luddism. What a great term that is. (Via Internet Commentator)

PS You find privacy luddites in the strangest places.

PPS. Should I not post over the next 3 days, it’ll be because this place has no wifi.

Opinion

The Meaning of Google

9 Comments

Everybody is trying to figure out what it all means regarding Google, and depending on your focus, you get different answers. Daring Fireball’s John Gruber goes the Noam Chomsky route, where newspapers don’t sell news to readers but sell readers to advertisers, ditto Google with search, and Spatially Adjusted buys that argument:

For all those thinking Google Earth is the next GIS platform, think again. Google only views it as a way to push ads on to your desktop.

But I think that is landing a little too harshly on one side of the debate about what Google means. I think there is more room for nuance, certainly when it comes to Google Earth.

Continue reading The Meaning of Google →

Notes on the political, social and scientific impact of networked digital maps and geospatial imagery, with a special focus on Google Earth.