Find Stuff By Minimum Bounding Rectangle

MySQL offers ENVELOPE() to find the minimum bounding rectangle of a geometric object. The result is a polygon with four segments, defined by five points. It took me a while to make sense of it, partially because the only documentation that I’ve run across so far for POLYGON() syntax is in the ENVELOPE() function mentioned […] » about 200 words

Working With Spatial Data in MySQL

It’s MySQL spatial data week here, though I am spreading out the posts to, um, ease the pain (or boredom). Anyway, here are some commands/functions I don’t want to forget about later:

Start with an existing table called geometry, add a spatial column and index it:

``` ALTER TABLE geometry ADD coord POINT NOT NULL; CREATE SPATIAL INDEX coord ON geometry (coord); ```

Insert some data; think in terms of POINT(X Y) or POINT(lat lon):

``` INSERT INTO geometry (coord) VALUES( GeomFromText( 'POINT(40 -100)' )); INSERT INTO geometry (coord) VALUES( GeomFromText( 'POINT(1 1)' )); ```

Get those X,Y coordinates back from the table:

``` SELECT X(coord), Y(coord) FROM geometry ```

Get points within a bounding rectangle:

``` SELECT MBRContains( GeomFromText( 'POLYGON((0 0,0 3,3 3,3 0,0 0))' ), coord ) FROM geometry ```

Calculating Distance Between Points In MySQL

MySQL has some powerful, and perhaps underused spatial extensions, but the most interesting functions are still unimplemented: “Note: Currently, MySQL does not implement these functions…”

Among those as-yet unimplemented functions is DISTANCE(). Alternatives can be found here and here, though neither is clean or simple. I wonder if a simple MBRContains() is good enough, though…

The New Plazes

Plazes, a kinda-cool, formerly networked-based geolocation tool has just been revamped. They’ve been promoting this change for over a month (I got a cool invite to the launch party, but couldn’t make the flight to Germany), and they’re continuing the push now that it’s live. I’ve used the new service for a few days, the […] » about 400 words

Plazes Updated

Wearing the badge “still beta,” Plazes, the free, network-based geolocation service, now sports a new coat of paint. Among the improvements is the Flash-based badge (above) and a much improved frontpage/dashboard that combines the map of known locations with the map of active users, formerly two separate screens. On the downside, I sort of miss […] » about 300 words

Google Geo News

This post started with Ryan sending me this link demonstrating a KML overlay of county borders of his bifurcated state in Google Maps.

Then I found this Roundup of Google’s Geo Developer Day (btw, I so wanted to be at Where 2.0) with tales of the new geocoding feature of the Google Maps API, more details about KML-in-Google-Maps, geotagging in Picasa, and the new Google Earth 4.0 beta.

And somewhere along the line, I ran across a link to SketchUp, Google’s 3-D modeler that seems built especially to put dimensional structures in Google Earth.

bsuite_geocode Plugin For WordPress

I’m a big fan of the WP Geo plugin, but I want more. My biggest complaint is that I want to insert coordinates using Google Maps or MultiMap URLs, rather than insert them in the modified story editor. So I wrote a bit of code that reads through the URLs in a post, finds the […] » about 400 words

Skyhook WiFi Geolocation

Old news from Gizmodo and Wi-Fi Networking News (quoting WiFi NN):

Skyhook has assembled a database of information about 1.5 million access points across 25 major cities in the U.S. by driving every street in every city. Their software records multiple data points per sample for directionality. Fire up their software on a laptop, and it compares the Wi-Fi information it sees with what’s in the Skyhook database, popping out a latitude and longitude within 20 to 40 meters.

Also geolocation related: Monopoly Live: London style.

GeoTagging Gets A New Meaning

Who doesn’t love tagging? No, tagging as in annotating, not graffiti. Anyway, Rixome is the latest among a bunch of plans/projects to enable tagging of geographic spaces/real-life environments. The good people at We Make Money Not Art had this in their post: rixome is a network and a tool that turns mobile screens into windows […] » about 300 words

When You Don’t Have A GPS…

Geolocation by GPS my be the most straightforward approach, but we mustn’t forget the other ways to get lat/lon coordinates. All current cell phones support aGPS positioning to comply with federal E-911 mandates, but not all phones make it easy for the user to get that information out of them. Still, some do and GPS-enabled […] » about 400 words

Geolocation Stumbling Block: GeoURL Host Down

A an old John Udell piece at InfoWorld hints at GeoURLs, but the GoeURL site is down, and has been for a while. The concept sounds interesting: you mark pages with coordinates, then use GIS to map those pages to geographic locations, finding pages and people of interest along the way.

To join GeoURL, you add this kind of metadata to your homepage:

I got interested in this sort of thing (geolocation) a while back, and I haven’t quite given up.

Update: Bjørn is right, GeoURL is back and I should have updated this post ages ago. Look here for more about geolocation on MaisonBisson. …And Bjørn’s website is worth a look too.