Howto use "raster to polygone" effeciently

[Anonymous User]

Original User: suburbian

Hi

I'am new at arcgis an therefore do not have a lot of experience.

I want to make polygons out of a raster image (jpeg/tif). Before that I also want to process the picture, so that in the end there are only 5 different colors/contrast values left. Alternatively Iam looking for a tool in arcgis that can to that all in one or so.

I managed to convert my raster image [screen1]
[ATTACH=CONFIG]22776[/ATTACH] via raster calculator tool from a coloured image to a black/white image. It then looks like this:
[ATTACH=CONFIG]22777[/ATTACH]

But when I now use raster to polygone tool, because of the many different grayvalues, the tool just makes a own polygon for every pixel.

Could someone explain me a good way of generalizing the grayshades or other way of good converting this image to polygons? For example it would be cool, to define 5 clases and each of this clases has a colorvalue range (ie 23-50 or so).

Thanks, Sub

[Anonymous User]

Original User: jbswain

Since you said classes, I would recommend using the multivariate tools in Spatial Analyst to perform image classification.  Performing either a supervised or unsupervised classification would create a single band raster and have it classified out.  Simply choosing one band or another is not enough.  I would keep the 3 band and then follow the image classification route.  There are great tools there with the image classification toolbar that can make the process smooth and intuitive.