Hi, I created a layerstack of two images in IDL using the following code. Let's say IMAGE A and IMAGE B have been chosen. both are of samples 2179 and lines 761. CODE: layerstack=fltarr(2179,761,2) layerstack(2178,760,0)=A layerstack[2178,760,1]=B envi_write_envi_file,layerstack,out_name='D:/filename.img' I get the result subscript out of range subscript encountered: layerstack. All i'm trying to do is to say the A is the first band of the layerstack and B is the second band. Where am i going wrong ? Thanks, Raghu