Extract by mask OUTSIDE

[EleanorFerguson]

Is there a way to get Extract by Mask to extract the area OUTSIDE?
I want to use Extract by Polygon with extraction area = OUTSIDE, but my polygon is in a feature class (too many vertices to input manually) so I have to use Extract by Mask. Is there a way to quickly import the XY coordinates from the feature class, rather than 1 by 1?
Or can someone suggest another way to remove the area inside the polygon from my DEM?
Thanks!

[TarunJaiswal]

Greeting!

If you have access to ArcGIS 10. You can use the Mask button on the Image Analysis window to get your desired output.

The masked output is added as a temporary raster layer to the table of contents. Next, please export the temporary raster (right click > Data > Export Data).

Hope this helps.

Tarun

[GayathriAlallasundaram]

Hi,

You could use the mask tool from the Image Analysis Window under the Processing tab.
The output is added to ArcMap table of contents, and this output is a temporary one, you will have to right click on the output and choose Data > Export Data to make it permanent. Please see this video for reference.http://screencast.com/t/xTSlWveYqd4

-Gayu

[curtvprice]

Is there a way to get Extract by Mask to extract the area OUTSIDE?
I want to use Extract by Polygon with extraction area = OUTSIDE, but my polygon is in a feature class (too many vertices to input manually) so I have to use Extract by Mask. Is there a way to quickly import the XY coordinates from the feature class, rather than 1 by 1?
Or can someone suggest another way to remove the area inside the polygon from my DEM?
Thanks!

Creating a raster mask may be what you want to do. I think this approach may be more likely to give you a good "snap" (cell alignment) than the image toolbar approach.

1. Set the extent, snap, cellsize environment to your DEM raster 


2. Convert your polygon to a raster, "pgrid". This gives you NoData for areas you want and a value inside the area you want to remove. It's a good idea to stop at this point and make sure you have what you want (or I should say, the opposite -- the NoData areas in this grid are those you will keep).


3. Use the Reclassify tool (or in 9.3, Reclassify in the SA toolbar) to convert the NoData to a 1 and your data cells to NoData.


4. Use this as your mask for Extract By Mask.

Another approach is to do steps 3 and 4 using Map Algebra instead:

Con(IsNull("pgrid"),"demgrid")