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. 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. 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: 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: 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. 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. Source.