Thursday, March 22, 2012

Calculating Land Lot Area with GPS Coordinates


As many readers are looking for a reference to calculate land lot area and perimeter with GPS coordinates data (Global Positioning System), so I create an Excel program specifically for that purpose. Download here.

Simply by writing longitude and latitude data of each vertex of a land lot, then the program will instantly calculate the area and perimeter. To avoid confusing, always use a clockwise direction to input vertex coordinates of the land lot. Counter clockwise direction will get negative result of area calculation.

In the picture below, I calculate area and perimeter of an area around National Monument (Monas, Jakarta). Picture shows GPS coordinates obtained from Google Maps. Please note that Google Maps uses latitude-longitude order.




Shown in the picture above the land lot is an irregular shaped polygon with 8 vertices (octagon). The starting point is the vertex at bottom left, then this point is also used as an end point to form a closed irregular polygon so that the program can calculate it’s area and perimeter. Total 9 GPS coordinates are written, as the starting point and end point at the same vertex. Coordinates are written in yellow cells, and they are sorted in clockwise order. On the right, there is a graph illustrating the measured polygon shape. In this example, octagonal polygon area is 231,339 square meters, and the perimeter is 1782.7 meters.

In the attached Excel workbook, there is also formula to convert GPS data with sexagesimal (degrees minutes seconds) format to become decimal format, then that decimal format will be used to calculate the area and perimeter of a land lot with irregular and regular polygon shaped.

This article is related to previous articles: calculation of polygons and calculate distance with GPS coordinates.

There are two methods for calculation of polygon area, by matrix and by rectangles. Matrix method is rather difficult to understand but the formula is simpler. And there is an article that explain about polygon perimeter calculation.





If you are looking for a reliable and high quality GPS equipment such as Garmin and Tom Tom, please check at "Best Sellers in GPS & Navigation Equipment".

17 comments:

  1. Thank you. Your area calculation spreadsheet was very helpful in the calculation of the area of body of water I own. Dan

    ReplyDelete
    Replies
    1. You are welcome...I use that spreadsheet to calculate GPS data at field. Once I get data and put it into that spreadsheet, it calculates immediately. No need special application, no need internet connection.

      Delete
  2. Could not download file. Is it still available?

    ReplyDelete
    Replies
    1. I've checked already with different computer and found no problem, the file is still available publicly for download.

      As that Excel file also contains other GPS calculations such as: heading, bearing, distance, etc; you can download the same Excel file from other articles about GPS in this blog. Please select 'Global Positioning System' label to find more articles about GPS.

      May be you should open it with Firefox or Google Chrome web browser in your computer.

      Thanks for your input, Heru.

      Delete
  3. Thank you so much! This is an amazing free tool that made my life so much easier as I was calculating the land size of over 100 farmers in Mali, West Africa!

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    Replies
    1. You are welcome, hope the tool will help you to produce more food in the future, and better economy for Mali's farmers.
      Rgs, Heru

      Delete
  4. magnificient..solved a big headache for me

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  5. Hi Maruza,

    Is the excel sheet still available? I need one to do my field work ..

    ReplyDelete
    Replies
    1. Hi JD.. just checked, the file is still available for download..
      You can check to below Google docs address also

      https://docs.google.com/file/d/0B-nhsU-fDuE6XzJLaEt2cDNJU0U/edit?pli=1

      Delete
  6. where is this file? the .xls or .xlsx file. The link does not link to an excel file.

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  7. Sorry..Got the file now but it is not working even in a new version of excel.

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    Replies
    1. I just checked and found no problem at all.. tx

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  8. i think the area is plain area how can i get the actual surface area of land using GPS?

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    Replies

    1. That Excel program has already calculated area on sphere surface, not plain area.

      If you need to calculate area with texture or with elevation, then you need 3 dimensional calculation. Surveyor softwares can do that, and AutoCad also can do.

      Regards, Heru.

      Delete
  9. Hi..
    Im working at several sites in Indonesia. Thanks to your Excel program with English and Bahasa guidance. Myself and my Indonesian crews can calculate and report land lot areas with their smart phones, helped by your Excel spreadsheet.
    Regards JJ

    ReplyDelete
  10. tnx

    area table works very nice! :)

    keep it up

    ReplyDelete

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