calculating areas from co-ordinates

[construct06]

i recently had an exercise where i had to calculate the cross sectional area at a road cross section. The information i had was in the form of levels and widths.

i had the following data,

eg: (x,y format)

(0, 103.21)
(0, 103.25)
(3, 103.32)
(6, 102.22)
(6, 102.27)

So basically its a trapezoidal shape taht i need to calculate area for. i solved this problem by creating a lisp in autocad, which could generate points which were in a text file. then i joined up and used area command. this was tedious and im sure there muist have been a way to do in excel.

 

[corus]

Use yakpol's famous spreadsheet for defining an area by co-ordinates.

http://yakpol.net/SectProp.html

corus

 

[SteveGregory]

Check out a surveying book. There are a couple of different methods of calculating land areas from a closed traverse. The same methods may be used for cross sections.

 

[IDS]

The spreadsheet here:

http://newtonexcelbach.wordpress.com/2008/03/25/section-properties-of-defined-shapes-spreadsheet/

will find area (and other section properties) both from coordinates and for a range of defined shapes.

Doug Jenkins
Interactive Design Services

http://www.interactiveds.com.au