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Blended Technologies » Blog Archive » Google Earth - Draw an n mile radious circle around a point

Google Earth - Draw an n mile radious circle around a point

Trying to visualize your non-compete agreement?
Trying to decide what jobs are in your commuting range?

Use my convoluted method below to do it in Google Earth:

1. Create a placemark in Google Earth where you want your circle centered.
2. Right click placemark.
3. select edit.
4. select advanced.
5. copy out the coordinates.
6. visit this page and turn them into decimal coordinates .
7. Then visit this page and enter the decimal coordinates.
8. Click generate and tell your browser to open the resulting link with Google Earth.

Note:
If your circle ends up in China, or you live in China and it ends up in America, then probably your Longitude should have been negative or vice versa.

And finally, after repeatedly following these steps.. here are the places my girlfriend can’t work!

Update: This bird watcher person has taken these instructions and made them even more detailed. So give that a try if you get confused from my instructions.

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14 Responses to “Google Earth - Draw an n mile radious circle around a point”

  1. bootstrap analysis Says:

    using google earth to map christmas count circles

    This is Christmas Bird Count (CBC) season, the roughly three-week period at the end of each year where teams of determined folks do single-day bird surveys of established 15-mile diameter circles (history here). Typically, participants are given a phot…

  2. Chris R Says:

    Thanks for breaking down the instructions. Another step might help us non-metric americans in converting miles to meters or feet to meters:
    http://www.metric-conversions.org/length/miles-to-meters.htm
    http://www.metric-conversions.org/length/feet-to-meters.htm

  3. Micah Says:

    A way to eliminate step 6 (and the issues with positive/negative coordinates) is to do this:

    1. Create a placemark in Google Earth where you want your circle centered.
    2. Right click placemark.
    3. select copy
    4. open Notepad (or other text editor)
    5. paste (CTRL + V) into Notepad
    6. Near the bottom you should see something that looks like
    7. Copy the values from and just below the
    8. Then visit this page and enter the decimal coordinates.
    9. Click generate and tell your browser to open the resulting link with Google Earth.

  4. Micah Says:

    Sorry for repost, but previous post was mangled (due to “<” and “>” characters)

    # Micah Says:
    October 12th, 2006 at 5:31 pm

    A way to eliminate step 6 (and the issues with positive/negative coordinates) is to do this:

    1. Create a placemark in Google Earth where you want your circle centered.
    2. Right click placemark.
    3. select copy
    4. open Notepad (or other text editor)
    5. paste (CTRL + V) into Notepad
    6. Near the bottom you should see something that looks like <LookAt>
    7. Copy the values from <longitude> and <latitude> just below the <LookAt>
    8. Then visit this page and enter the decimal coordinates.
    9. Click generate and tell your browser to open the resulting link with Google Earth.

  5. Micah Says:

    Could you post the source code to your PHP script? I’d like to use/modify it to generate several circles. I’m doing basically what you’re doing and I’d like to input all the coordinates at once and get a single KML file that has all the circles.

  6. Greg - CEO/Founder Says:

    Hi there, Micah.

    You must be mistaken, I don’t have any PHP script. The links I point to in the post are external pages so you’ll want to contact those authors if that’s the functionality you need. But in any case I’d certainly be interested to see your final solution, so keep me posted.

  7. Jack Harlan Says:

    This worked great! Couple of minor points:
    It’s not necessary to do the conversion of your lat/lon
    points by writing them down, then going to that external
    webpage.
    In GEarth, go to “Tools”,”Options”,”View” and change the
    Lat/lon view to “Degrees” instead of “Degrees,Minutes,Seconds”.

    This is a mysterious webpage:
    http://dev.bt23.org/keyhole/circlegen/
    Doesn’t seem to have any real home page….
    I’d like to know how to create circular arcs rather than
    complete circles.

  8. Elliot Says:

    Hi All Experts,
    Does anyone use google earth images as ground image planes for use in aerial scenes. I know how to stitch them together but are there any tools or tricks to make sure that the images are at the same height, angle and such to make sure they stitch well. I know in the pro version you can get bigger images but im not going to pay for the pro version when i could stitch multiple images together…

  9. Drawing circles in Google Earth | Juicy Geography’s Google Earth page Says:

    […] I looked around for a neat way to draw circles in Google Earth and discovered this KML generator page via Blended Technologies that will create perfect circles drawn to scale and based on the positon of your choice. […]

  10. jenny Says:

    please i need know how get the radious

  11. R Jolly Says:

    I saved the circle in ascii format (.kml). This file shows that the circle has been created as a string of tiny straight lines drawn on the surface of the earth. The line coordinates are in terms of (latitude,longitude,altitude=0). Can someone tell me the equation used for defining a circle on the surface of earth given its centre and radius? This can then be used for writing your own code to create multi-circles or arcs, as required by some people on this page.

  12. R Jolly Says:

    I spent some time searching for equations to generate a circle on the earth’s surface. I found two indpendent methods that I programmed, uploaded the circles into Google Earth and compared with those from Blended Tech. There are not so insignificant differences. The Ruler tool shows that the circle from Blended Tech is the most accurate. Can someone share the equations used here so that I may incorporate them in my software?

  13. Greg - CEO/Founder Says:

    R Jolly, this is the website does the actual circle generation. So you’d want to contact that creator of that page to find out the algorithm he/she uses.

    I didn’t find any contact information on that page though. The next best bet would be for you to post your question on this thread where the author of that page announces his circle generator.

  14. nickg Says:

    Hi folks, I came up with my own circle generator, which also does regular polygons and star-like things.
    The code is open source and can by found at

    http://code.google.com/p/kmlcircle/

    Take a peek.

    –nickg