topic Clip Outside Polygons: Vector - Raster Data in Geoprocessing Questions

Clip Outside Polygons: Vector - Raster Data

MikeMichalek — Thu, 03 Apr 2014 15:46:49 GMT

I am trying to "Clip" a vector polygon shapefile (e.g., multiple lakes) out of a panchromatic black and white aerial image (raster). I see that using the CLIP tool in ArcMap 10, that the function only allows me to clip "inside" these polygons. Is there a way that I can REVERSE this function so that I can get the lakes out of the raster, while still keeping everything else in the raster image?

Might need to convert vector to a raster? Could you please include steps?

Thanks!

Re: Clip Outside Polygons: Vector - Raster Data

HuongPhan — Fri, 04 Apr 2014 06:13:40 GMT

I never find anytool to clip outside polygons (Maybe it locates somewhere:-) ). In order to do that, I do as follows:

1. Make the polygon edittable, and select all features in this file
2. In Create Feature window, choose Auto completion Polygon in Construction tools, and draw a big rectangular covering all polygons, and covering the raster extent also. You will get a new polygon with holes which are your lakes. Export the new polygon to a new file.
3. Clip raster by this new polygon file.

It does not take much time, doesnt it?

Huong

Re: Clip Outside Polygons: Vector - Raster Data

DuncanHornby — Fri, 04 Apr 2014 12:51:45 GMT

Mike,

Would it be a better description to say you wish to erase (set to NODATA) the cells of your raster where the lake polygons are?

This can be achieved with a simple model but better still someone has created a set of very useful tools, one a raster erase tool.

The toolbox is called Spatial Analyst Supplemental Tools and is found here.

Its worth spending some time checking out what the user community has uploaded as someone has nearly always done it before, good news for the rest of us!

Duncan