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Thursday, December 18, 2008

Google Mapping a CBC Circle

I've previously posted about how to use Google Earth to plot out a Christmas Bird Count circle (mainly riding on the coattails of Bootstrap Analysis)- a great way to virtually scout and see count territory boundaries, etc.

Recently, I had correspondence from Chris Hill who decided to use Google Maps to set up his count circle territories, citing the ease of sharing the maps and for the potential of letting others add to the map, too. The only hitch seemed to be getting a good 7.5-mile radius circle drawn- Google Maps has line & polygon tools but not a circle generator. Curious, I did a search and it turns out that you can import a .KMZ file that Google Earth generates into Google Maps- easy directions are posted on the Google Lat Long blog. Ba-boom- the best of both worlds. You can work up your circle &/or territories in Google Earth, import it into Google Maps, and then share the URL with whomever. You can even embed the Google Map in your blog or other web page- see below.

Basically, here are the steps, summarized from Bootstrap Analysis and then adding the step of importing the .KMZ file into Google Maps. First, you've got to get the Lat/Long coordinates of the count circle center. You can get this by hovering your pointer over the spot in Google Earth and noting the coordinates, or you can get the coordinates that are on record with Audubon through the compiler's page (although many of these aren't too accurate, having been estimated from paper maps, often not at very good resolution. National Audobon is requesting updated count center coordinates and descriptions-see here.)

If your Lat/Long is in minutes/seconds then you will need to convert them to decimal- easily done here. (Note that if you acquire the coordinates from Google Earth they will already be decimal if you set that format in the preferences- also the default setting, I think.)

Then you link to the free KML Circle Generator, plug in your center coordinates, and set the radius to 12,070.08 meters (the equivalent of 7.5 miles.) This will return a link that you follow to download a .KML file which will open in Google Earth as a nice circle demarking your count boundary. Right-clicking on it and selecting "Properties" (or "Get Info" on a Mac) will let you re-name it, change the color, change the thickness, change the opacity, etc. Then, if you want, you can use the line, polygon, and placemark tools to further divide and/or organize your circle. I also put a placemark at the count center. Now you've got a collection of map elements that you can save as a .KMZ file by right clicking on the folder and choosing that option.

Finally, go to Google Maps and choose the "my maps" option. Select "create new map", and give it a name. Right above the name there are two links- "collaborate" and "import". Choose the import option and find your .KMZ file wherever you saved it. Google Maps will pull the circle and whatever else you created in Google Earth to your new custom online map. You can further edit it in Google Maps with the line tool, polygon tool, placemarks, etc. I haven't explored the feature much, but using the "collaborate" link lets you give editing privileges to others. Once your map is ready and saved, you can use the print, send, and/or link options to share it with others.

Anyway, another great, free way to share and collaborate with your fellow counters or other organized birding tasks requiring maps. Lots of CBCs still to come- good luck & have fun out there! Update: I've got all of the Boulder CBC territories on my Google Map but they don't all show up on the little embedded version- click on it to get to the bigger version with all territories, navigable between pages 1 & 2 of the map. ;-)

View Larger Map

3 comments:

Left Handed Birder said...

Yay! Thanks Bill. I was pondering using Google Earth. I think I'll give it a go.

Patrick Belardo said...

Awesome! I had wanted to do this for my count, but couldn't easily figure it out.

Bruce Webb said...

Last year I realized it is possible to get my miles walked using Google Earth's "show ruler" feature.