asr99slg

Correct garden sizes using intersect, but a step too late!

Discussion created by asr99slg on May 20, 2011
Latest reply on Jun 13, 2011 by asr99slg
Hi GIS forum,

I want to calculate the area of polygons (gardens) for each cell within a 250m grid. I have used the intersect function to ensure that garden polygons overlapping the grid lines are truncated so that there is no double-counting of gardens. Now I have garden polygons that have been artificially split by 250m grid. Unfortunately, when I check the sum of gardens within each grid cell, it tells me the original larger garden size (e.g. 1185 sq. m.) instead of the new smaller sum (e.g. 1060 sq. m.) when the area that should have split off is the difference (125 sq. m.)

But when I recalculate geometry it of course, gives me the 250m x 250m grid size = 62500 sq. m!! Interestingly, if I put in an extra calculation step, e.g. create buffer -1m around all gardens - it then gives me the correct answer - but a step late. I verified this onscreen using the measurement tool.

Can I streamline my method so it I get the correct answer at the point when I expect it?

Thanks,
Sarah

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