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Scaling Polygons using Latitude and Longitude

August 08 2010 | 3 comments
Categories: Map Data

I have project where I need to take a polygon on a map and draw a shape around it that is X number of feet. Is this possible to be calculated?

Mapping Center Answer:

An easy way to do this is to set the properties of the data frame to a coordinate sytem that uses feet (e.g., State Plane), draw the polygon in the data frame and then use the drawing toolbar to draw the shape around the polygon. Once you have drawn the shape, you can modify its dimensions to get the units you need. (e.g. a square of 100 ft. on each side to make a 100 sq. ft. polygon or a circle that is 100 sq. ft. so its radius is 5.64 ft. - or the diameter is 11.28).  Once you've drawn the polygon, right click the data frame and select the Convert Graphics to Features option.  Note that you will likely be then saving the polygon you draw in the coordinate system of the data frame, so if you project it to some other coordinate system, the shape of the feature will change.

Shape Change posted by Branden Allmon on Aug 10 2010 5:23PM
I don't think this will provide an exact X' buffer. It needs to be X' feet from any point on the polygon. A square with a 100' buffer would be a larger square with rounded corners. A drawing tool is not accurate enough. Thank you for your help. I am really struggling with this one. I think this is the solution http://resources.esri.com/help/9.3/arcgisserver/apis/javascript/gmaps/help/google_start.htm#topics/samples/util_buffergraphic.html
buffer tool? posted by Christopher Johanson on Aug 24 2010 1:53PM
Why wouldn't the buffer tool work?
Buffer will work for ellipses posted by Aileen Buckley on Aug 24 2010 5:26PM
Thsi will work for an ellipse but if you need to draw any other shape, e.g., a rectangle, it won't work. The example in the answer is for a square or a circle.

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