arcgis-10.0arcgis-desktoparcmapareacoordinate system
I've got a polygon featurelayer in ArcMap 10.
The coordinate system of the featurelayer's featureclass is web mercator.
The dataframe of the map uses an equal-area projected coordinate system.
I've got a field on the featureclass called Acreage.
I'd like to calculate Acreage based on the polygon's re-projected area (into that of the dataframe's projection). I don't want to create a new featureclass to do this.
Is there an easy way to do this in ArcMap 10?
The easiest way is to go to the TOC table of contents...
right click the data frame (usually named layers).
Select properties. and the coordinate system tab.
then find the gcs system you would like to have as the final output
set the "document " to that by OK'ing out of the dialogs.
Then when you right click on the layer you want re-projected and select >Data
export data.
You get the export dialog.
Select the "same as data frame" option..
Give it a location and you are done.
I think you can.
Just define the Spatial Reference in WGS-84 and use cursor using this Spatial Reference.
Coordinates are specified in the spatial_reference provided, and converted on the fly to the coordinate system of the dataset.
Fore more detail see this.
Best Answer
If you are doing this within Arcmap and you have an open table, have you ruled out using the Calculate Geometry option after right-clicking on the field. If your dataframe is already set in the projection that you want you should be able to use its coordinate system without the prior projection issue.