topic Re: How to get the pixel counts. in Data Management Questions

How to get the pixel counts.

Anonymous User — Thu, 15 May 2014 17:06:00 GMT

Original User: takeofuture

I have a trouble with getting pixel count on the attribute tables.
The below is what I did
1) Download USGS imagery (glovis.usgs.gov)
     Downloaded like follows
[ATTACH=CONFIG]33841[/ATTACH]

2) Raster Processing -> Composite Band Function Create Composite Image
     (Follow the Link below: http://www.uvm.edu/~joneildu/Video/GIS_Open/LandsatArcGIS/Landsat%20ArcGIS.html)

3) The view looks fine by RGB=321 or RGB=432 etc, I clip the image.
   (I follow the supervised classification, following the instruction the esri book: Using GIS and Remote Sensing Workbook)
   [ATTACH=CONFIG]33842[/ATTACH]

4) After I classify by supervised classification and export the data, It prompt to pixel depth and I clisk yes

5) The resulted attribute table looks very strange.
[ATTACH=CONFIG]33843[/ATTACH]
    Is this something wrong with data?

Ok, My question now is,
Is there any way, I can get the pixcel count from here,
If not, what is wrong (Seems to be original raster data?)? and how to fix it.

Re: How to get the pixel counts.

Anonymous User — Fri, 16 May 2014 14:18:20 GMT

Original User: iamurray

Looking at the attribute table you posted, the red blue and green fields are showing the amount of r/g/b respectively that are used in your classification symbology(represents their colors on the maps.

Statistics about rasters can be found by right clicking on the raster in the Table of Contents, and selecting the source tab.

If you need to calculate statistics you can use the Calculate Statistics (Data Management)

Re: How to get the pixel counts.

TakeoShibata — Fri, 16 May 2014 15:50:13 GMT

Hi Thank you fro your reply.
The issue is I am not intrested in RGB count (How each color formed from 3 basic color)
I rather want to get the count of pixel.
When I followed the workbook with the data included the book, this is automatically created
But when I did the same procedure using the downloaded data by myself, it does not counted and seems to be some issue.

[ATTACH=CONFIG]33873[/ATTACH]

Counting should be straight forward since the classification is there but I do not know how.
Statistic does not show any and source does not have any count.
Any advise?

Re: How to get the pixel counts.

Anonymous User — Fri, 16 May 2014 16:17:03 GMT

Original User: iamurray

Again, have you tried to run the Calculate Statistics (Data Management) Tool? It will generate statistics for your raster since it does not already have them.

It can be found in ArcToolbox>DataManagement>Raster>RasterProperties>CalculateStatistics.

Re: How to get the pixel counts.

TakeoShibata — Fri, 16 May 2014 16:39:42 GMT

Hi Thank you!
I got the result by Build Attribute Table processing

Thank you