I have a site (polygon) of irregular shape and need to define an area around that polygon. The buffer only allows to calculate distance from the sides of the polygon. Is there a way to define a buffer based on area or create an area of specific size (say 10000 ha for example ) around a polygon ?
If you have a single site... create a new featureclass, draw a rectangle and edit the coordinates of the corners to give you the desired area from your chosen width and height. You can then shuffle it around and/or rotate it to get the layout you want. Humanware is going to do a better job in this case
Kind of an interesting puzzle! Maybe you could explain your use case (that is, what are you trying to accomplish). I am curious!
Here is a way to create a circular buffer, centered on the centroid of the polygon, of a specified total area outside your source polygon.
Watch your units, if you are using Shape_Area everything should be in map units or square map units (ie feet, meters).
1. Add a field of type Double to your polygon feature class. (xarea)
2. Calculate this field to the area plus your desired buffer area
3. Calculate the radius of a circle for this area, the Python expression would be (math.pi / xarea) ** 0.5
4. Convert your polygons to points with the Feature To Point tool.
5. Buffer these points using the calculated radius value.
Does the buffer polygon around the site polygon need to be a specific shape? For example, Curtis suggested a circular buffer polygon, does that work? Would a rectangle be better, or worse?
It can be done
but not without coding. It entails some work.