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I have a land cover classification derived from Landsat TM imagery - I created this classification using ENVI. I would like to edit individual and groups of cells in some areas of the classification in order to improve the accuracy of the output by comparing it with aerial imagery.

Is there a way, using ENVI or ArcGIS, to manually edit large groups of cells by selecting them and assigning them to a new or existing class? I am aware of merging methods based on class statistics, but the area I'm classifying has a high amount of spectral confusion due to thin cloud cover - it seems like a manual edit is the only way to go.

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1  
Have you considered running atmospheric correction on the base image, such as dark body subtraction? – Aaron Nov 13 '12 at 13:24
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@Aaron Could you guide a sort of tutorial how omitting atmospheric correction increases misclassification. Thanks – SIslam Feb 22 at 10:11
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@Sislam I would refer anyone interested in atmospheric correction to the following paper: Song, C., Woodcock, C. E., Seto, K. C., Lenney, M. P., & Macomber, S. A. (2001). Classification and change detection using Landsat TM data: when and how to correct atmospheric effects?. Remote sensing of Environment, 75(2), 230-244. unc.edu/courses/2008spring/geog/577/001/www/Song01_RSE.pdf – Aaron Feb 22 at 12:18
up vote 14 down vote accepted

I don't think there's a really simple way to do this, but one way would be to:
Create a new polygon layer and create polygons over the areas you want to change the values of.
Code the polygons with the desired land cover value.
Convert the shapefile to a raster.
Use the Raster Calculator to substitute the new values.

Con(("POLYRAST" > 0),"POLYRAST","CLASSIFIED")

That's about the simplest way I can think of. :-/

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That's a decently simple solution - I can just digitize polygons over the aerial imagery and follow the steps you outlined. I wish there was a way to do it simply like MSPaint for rasters, but as far as I know MSPaint doesn't support Geotiffs :$ – Radar May 9 '12 at 23:10
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@radar, it's possible to use any graphics program that understands regular tiffs: 1) save georeferencing, 2) paint image -- being careful not to change dimensions, or using colour values outside the valid data range, 3) save, 4) restore georeferencing from #1. This work flow is worth a new question on it's own; the closest answer I see so far is gis.stackexchange.com/a/24798/108, while the subject for this Q gis.stackexchange.com/questions/76572/touch-up-tool-for-rasters is perfect (body is a bit too specific). – matt wilkie Mar 7 '14 at 23:01
    
Thanks forestman - your "Con" statement just saved me a bit of time, and I learned a new little trick. Much appreciated. I 1 upped you!! – dklassen Apr 4 '14 at 22:40

The editing can be done with the ARIS Grid & Raster Editor for ArcMap: www.aris.nl/gridrastereditor_arcmap

The ARIS Grid & Raster Editor adds a toolbar to ArcMap. This toolbar provides a set of tools to change the value of one or more cells. With these tools it is possible to:

  • change the value of a single cell or pixel (pencil)
  • draw a free line (pencil/freehand)
  • draw straight lines from one point to another (line)
  • draw a solid polygon (polygon)
  • set pen size in cells to be affected while drawing
  • change the value/color of a zone of cells with identical values (paintcan)
  • replace one value with another value in the entire raster (value replacer)
  • create a selection area in the map to limit the working area for the above operations (edit area)
  • select new cell value from the grid (color picker)

Grid & Raster Editor for ArcMap example: pixel edit of single cells with pencil/freehand

Supported raster formats

Most single and multi-band raster formats editable by the ArcGIS Object Model are supported by the ARIS Grid & Raster Editor. The supported raster formats include:

  • Band interleaved by line (BIL)
  • Band interleaved by pixel (BIP)
  • Band sequential (BSQ)
  • Bitmap (BMP)
  • ENVI Raster (e.g. DAT, BIL, BIP, BSQ)
  • ERDAS IMAGINE Image (IMG)
  • ESRI GRID
  • File Geodatabase Raster (GDB, FGDBR)
  • Personal Geodatabase Raster (MDB, PGDB Image)
  • Tagged Image File Format (GeoTIFF, TIFF)

For multi-band rasters the Red, Green and Blue bands (RGB) can be edited simultaneously.

Available as 5-day free trial on www.aris.nl/gridrastereditor_arcmap. Current pricing is 330 Euro.

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1  
Very nice, but rather expensive. – nadya Nov 13 '12 at 22:49
    
Very good tool! Thanks. – SIslam Feb 22 at 11:12
    
Please, merge your acconts. @Rinke. – Andre Silva Mar 1 at 14:14

At first try to lessen manual work! Use post-classification tools to do this. If you need to refine further then try below--

I follow two ways- First one is vector editing and converting vector to raster if needed and second one is editing raster directly.

  1. In ArcGIS: Export classification into vector and use attribute transfer tool to manually refine your classification as you,this may need editing. want.
  2. In eCognition: If you have access to eCognition you can use several way to refine your classification one of these are import classified image into eCogniton and segment (with proper algorithm and parameters) based on color thereafter use manual classification as below-

demo

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I've used arcscan and the paint tool to edit individual pixels but this was on a grid which had only 2 values for pixels.

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Yeah! This very much effective for monochrome cadastral maps!! – SIslam Feb 22 at 10:13

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