# largest area polygon

I have a layer of polygon shapes, I know this could be a quite easy question to answer but I am a beginner and probably I am not using the right concept or terminology when looking at the desktop help of ArcGIS as I have not find anything useful. I would like to find the polygon with the largest area, and from it then calculate its center coordinate, any suggestion it would be very helpful thanks!

• how can I sum all the polygons into one and crea a layer of them which it result it will be one big polygon from the previous one do you know what I mean? – Enriue Nov 13 '14 at 11:41

I would do this in two steps. Firstly add a new field to contain the area of your polygons (see below) give it a basic name such as Area and make the type double (see this for more details).

You can then calculate the geometry of your polygons in your new field by right clicking the field heading and selecting Calculate Geometry. Which will bring up the window below:

Once you have done this double click the field heading and that will sort your polygons by size allowing you to identify the largest.

The second step is to run the Feature to Point tool creating your centroid. You can either run this for every polygon in your layer, or if you select the largest (it will be highlighted in bright blue in your attribute table) it will create the point just for this polygon.

Then if you want the co-ordinates for the centroid add two fields to this point layer - an X and Y field, then as before open the calculate geometry window - you will then be able to select to either calculate the X or Y coordinate.

Hope that helps!

• Thanks a lot is really helpful! I would like to ask another issue, how can I sum all the polygons into one and crea a layer of them which it result it will be one big polygon from the previous one do you know what I mean? – Enriue Nov 13 '14 at 11:14
• theis tool is called "dissolve", but please ask new questions in new posts. – radouxju Nov 13 '14 at 11:19
• Glad it helped, please mark as the accepted answer so other people can find it in the future. As @radouxju said it's best to ask new Q's in a new post. But dissolve is what you are after: resources.arcgis.com/en/help/main/10.1/index.html#//… – MAJ742 Nov 13 '14 at 11:22