topic Re: Raster Pixel Selection in Data Management Questions

Raster Pixel Selection

DaniMaynard — Wed, 09 Nov 2011 17:08:40 GMT

Ok...this seems like it should be a very basic function to me...but I have a raster (DEM with elevation values) and I would like to select all the pixels with an elevation of 1500-1600 meters and show them as a different color, or even create a new raster with just those pixels. How can I do this without converting this to a vector first?

Using Arc 10 sp2.

Re: Raster Pixel Selection

EricRice — Thu, 10 Nov 2011 14:31:57 GMT

Hi Marie,

In terms of showing/displaying the data, you need the classified renderer to do this. You can set class breaks at 1500 and 1600 so that range will have a specific color. Is your data integer or float? If you make a new raster with those values do you want the new raster to maintain the orginal values, or would you be fine with a binary output where 1 means the pixel is within those values and 0 means its not? Depending on what you say, I'll either direct you to the Raster Calculator or the Extract by Attribute tool. There are multiple ways to do this in ArcGIS. I just need to know what you want for your output. If you want to discuss your goals offline, let me know and I'll shoot you an email.

Best Regards,
Eric

Re: Raster Pixel Selection

DaniMaynard — Mon, 21 Nov 2011 17:01:36 GMT

Hey Eric -

Let me take this a bit further and say that I only want to select the pixels within my AOI which is a very small subset of the original world wide dataset. I have a shapefile of the boundary that I'd love to use as input to a tool, but I have not yet found a tool that will take a polygon vector as input for a selection on raster pixels.

Once I have my AOI pixels selected I would like to create a new raster, complete with the original values (not binary).

Re: Raster Pixel Selection

EricRice — Tue, 29 Nov 2011 16:37:19 GMT

Hi Marie,

Both of the tools I mentioned honor the Mask Environment Setting. You can set your polygon as the mask. Alternatively, you can Clip the data using your shape to create a subset, then perform any additional processing on the smaller dataset.

Regards,
Eric

Re: Raster Pixel Selection

MaitphangSyiem — Wed, 28 Dec 2011 09:10:42 GMT

Hi everyone need help, georeferencing of the raster data works fine, the pixles values also are shown but when view the same raster data in another system it shows another pixels value...........is this a bug.....well using Arcgis 10 editor evaluation licence........can any one explain....

Re: Raster Pixel Selection

GayathriAlallasundaram — Wed, 28 Dec 2011 14:16:32 GMT

Hi everyone need help, georeferencing of the raster data works fine, the pixles values also are shown but when view the same raster data in another system it shows another pixels value...........is this a bug.....well using Arcgis 10 editor evaluation licence........can any one explain....

Hi,

Please try to install the latest sevice pack which is ArcGIS Desktop 10SP3 and then try to see if the issue occurs, click the link below to install 10SP3

http://resources.arcgis.com/content/patches-and-service-packs?fa=viewPatch&PID=17&MetaID=1807.

Regards,
Gayu