Area of Irregular Polygon

[Alex Tweedly]

Roger,

try this (I've done some minimal testing, so do please check it ...)
it assumes the polygon is closed

function getArea pPts
    if line 1 of pPts <> line -1 of pPts then return 0
    put 0 into tArea
    put empty into oldL
    repeat for each line L in pPts
       if oldL is not empty then
          put item 1 of L - item 1 of oldL into dx
          put item 2 of oldL + (item 2 of L - item 2 of oldL) / 2 into avgY
          put dx * avgY into thisArea
          add thisArea to tArea
       end if
       put L into oldL
    end repeat
    return abs(tArea)
end getArea

NB you could shorten it, but I left each math step separate to make it 
easier to debug / check

-- Alex.

On 07/11/2015 22:29, Roger Guay wrote:
> Thanks very much, Scott. I do have a long points list that I would have to manipulate even before apply this technique. I’m not looking forward to that, but I may have to go this route.
>
> Cheers,
>
> Roger
>
>
>> On Nov 7, 2015, at 12:05 PM, Scott Rossi <scott at tactilemedia.com> wrote:
>>
>> It looks like this could translate to LC if you have the point locations
>> of your polygon:
>>
>> https://www.mathsisfun.com/geometry/area-irregular-polygons.html
>>
>>
>> Regards,
>>
>> Scott Rossi
>> Creative Director
>> Tactile Media, UX/UI Design
>>
>>
>>
>>
>> On 11/7/15, 2:01 PM, "use-livecode on behalf of Roger Guay"
>> <use-livecode-bounces at lists.runrev.com on behalf of irog at mac.com> wrote:
>>
>>> Can anyone think of an easy way of getting the area of an Irregular
>>> polygon?
>>>
>>> Thanks,
>>>
>>> Roger
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