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Land area calculation spreadsheet 3
- Thread starter RMPE
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DMD is double meridian distance. It’s the basic calculation method for areas when you have coordinates or latitudes and departures for a traverse.
For more information see any basic survey textbook.
Rick Kitson MBA P.Eng
Construction Project Management
From conception to completion
For more information see any basic survey textbook.
Rick Kitson MBA P.Eng
Construction Project Management
From conception to completion
Look up Double Meridian Distance (DMD) in old Surveying books. You'll find a great way of calculating enclosed irregular areas using the coordinates of the points. Takes a little imafiniation but is really expedited using computerized spreadsheets.
DMD is a simple method to program into a spreadsheet.
I once programmed a HP-25 that only had 49 program steps to calculate areas using DMD. (Took all 49 steps but was able to do it.)
If you need someone else to program the sheet for you then you do not understand DMD or spreadsheets or both and should get back to basics before you use the results so that you can fully understand them.
Basically you calculate the coordinates of the end points of every line in the traverse. The x coordinate is known as the dep or departure and the y coordinate is the lat or the latitude. This calculation is basic trigonometry.
DMD is simply the sum of the deps for each end point of the line. The area is then the DMD multiplied by the difference in the lats divided by 2. You continue this around the traverse for every line in it and sum all the areas. Simply proceed in the same direction around the traverse for each line.
For example consider the simple traverse bounded by the points (0,0), (1,1) (1,0). This forms a right angle triangle with an area of 0.5 units.
First line (0,0) and (1,1) Area = DMD x delta lat/2=(0+1)(0-1)/2=-0.5
Second line (1,1) and (1,0) Area =(1+1)(1-0)/2=1.0
Third line (1,0) and (0,0) Area= (1-0)(0-0)/2=0
Area is then –0.5+1+0=0.5
Note that you might get a negative area for some calculations. This is normal and would depend on the configuration of the traverse.
Rick Kitson MBA P.Eng
Construction Project Management
From conception to completion
I once programmed a HP-25 that only had 49 program steps to calculate areas using DMD. (Took all 49 steps but was able to do it.)
If you need someone else to program the sheet for you then you do not understand DMD or spreadsheets or both and should get back to basics before you use the results so that you can fully understand them.
Basically you calculate the coordinates of the end points of every line in the traverse. The x coordinate is known as the dep or departure and the y coordinate is the lat or the latitude. This calculation is basic trigonometry.
DMD is simply the sum of the deps for each end point of the line. The area is then the DMD multiplied by the difference in the lats divided by 2. You continue this around the traverse for every line in it and sum all the areas. Simply proceed in the same direction around the traverse for each line.
For example consider the simple traverse bounded by the points (0,0), (1,1) (1,0). This forms a right angle triangle with an area of 0.5 units.
First line (0,0) and (1,1) Area = DMD x delta lat/2=(0+1)(0-1)/2=-0.5
Second line (1,1) and (1,0) Area =(1+1)(1-0)/2=1.0
Third line (1,0) and (0,0) Area= (1-0)(0-0)/2=0
Area is then –0.5+1+0=0.5
Note that you might get a negative area for some calculations. This is normal and would depend on the configuration of the traverse.
Rick Kitson MBA P.Eng
Construction Project Management
From conception to completion
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