Monthly Archives: October 2007

I’m on National TV :)

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OK, maybe not the same nation as y’all, but it’s still pretty cool.

This morning, a segment on CTV‘s Canada AM called "Canadians on the Cutting Edge" featured the work I’ve done with Google Earth for my employer, the City of Nanaimo.

Jason Birch on Canada AM CTV

(click image for video, or follow this link: http://tinyurl.com/2oshr7 )

I’m still playing on my 15 minutes of fame from some articles in the Vancouver Sun and Globe and Mail (paid content, but there’s an excerpt on Carsons Post). At the time, local papers picked it up, as well as local broadcast and cable TV.

I think that this puts me over the 15-minute mark, so hopefully it’s over now :)

-J

OSGeo BC – Formation and First Meeting

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Just a quick note about the formative OSGeo British Columbia Local Chapter

If you are in BC and interested in the promotion or use of open source geospatial (and I haven’t already hit you with the flood of spam to my frequent hangouts), make sure you get signed up and plan to attend our first meeting on November 15 between 11:00am and 2:00pm. For this first session, we will be meeting simultaneously in Victoria and Vancouver, with videoconferencing connecting the sites. A tentative agenda has been drafted in the wiki, but if you have strong feelings one way or another, speak up on the mailing list.

I am extremely happy with the interest in this organisation from all levels of government (with a strong showing by local government – yay team!), private industry, and consulting agencies. I believe that this shows two things. First, that hosting FOSS4G in your region helps to build an awareness of the capabilities of open source geospatial software, and second, that open source geospatial is now at the level that it merits serious consideration as part of any enterprise geospatial strategy.

Even if you cannot attend the initial meeting, I would strongly encourage you to sign up for the mailing list (or its web-based shadow at Nabble) and spark up a conversation.

-J

Better Network Links in Google Maps

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OK, so I’m breaking a promise; guess I’m a certified fanboi.

Over at Google LatLong, they just announced increased limits for KML in Google Maps. The real news, though, is that they are now following network links based on zoom extent. This means that there are more applications where you can just publish a KML service rather than messing with the Maps API.

For example (careful, it can be pretty sluggish in certain browsers) here’s my city’s main KML file displayed in Google Maps:

Nanaimo KML Master File in Google Maps

As cool as this is, in many cases you still have to design your KML files differently than you would for Google Earth. The browser is very limited in the amount of data that it can display–so you have to send back less data–and certain visual elements are handled differently in Maps. To deal with these limitations, there are several things that immediately come to mind as potential performance gains:

  • In your network links, check the bounding box extents before returning data that is too dense for the current zoom level. Basically you just take the max (or average) of width and height, and don’t return data unless it’s lower than a predetermined value. This was the original method for controlling content in Google Earth before Regions were introduced, and is quite effective in two dimensions.
  • Stay away from fancy elements like multi-geometry for mouse-overs. They don’t work in Maps. If your information can be communicated using points, then stick with points.
  • If you must use lines/polygons, simplify your data so that unimportant vertices are removed
  • Keep the information in your descriptions to a reasonable level.

It may also be worth experimenting with Regions to see if they are supported and make a performance difference.

Check out the original post for more examples of KML in Maps.

-J

Circular Reference: Google Earth and YouTube

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I wonder how wrong the infamous 80% rule is. It seems like more and more content which has not been thought of as geospatial is getting added to the world’s most popular geo-browser.

Here’s a funny shot, it’s me and my boss talking about Google Earth in a YouTube video, inside of Google Earth. Don’t look too close or you’ll get sucked in by the infinite recursion :)

Jason and Guillermo Talking about Google Earth INSIDE Google Earth

Sorry for jumping on the “everyone posts about Google announcements” bandwagon… I usually try to avoid it.

-J

Who said web-based GIS was hard?

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Whoever it was, they apparently forgot to tell Christopher Schmidt. When you put OpenLayers together with his new WPServer application, several standard GIS operations are as easy as clicking a button. And WPServer is available under the same license as FeatureServer OpenLayers .

Here’s an animated GIF showing the fun I had playing around with the WPServer Demo:

WPServer Demo

What I did:

  1. Added several polygons in stream mode representing the Mediterranean and islands
  2. Ran a symmetric difference on all of these polygons, to create a single hole-y polygon
  3. Smoothed (a bit too much) the polygon
  4. Buffered the entire polygon
  5. Generated a convex hull
  6. Added another polygon (it looked too much like a mushroom to resist)
  7. Buffered the new polygon
  8. Dissolved the two polygons together
  9. Replaced the dissolved polygon with a centroid
  10. Buffered the centroid
  11. Generalized (not as much this time) the polygon

What was the point? Well beyond having fun, just being able to create the initial complex hole-y polygon was something that I hadn’t seen in web-based GIS before. Very cool. All of the other operations were useful too, though maybe not so much in this example. Do yourself a favour and play around with it a bit.

What’s the downside? Christopher can no longer say that he doesn’t do GIS :)

-J