You will want to use the Band Math tool for this, rather than the Sum Data Bands tool. The latter is designed to sum the different bands contained in one file. The former lets you do all types of math between bands in the same image or in different images. The Band Math expression you'll want to use will be something like: b1+b2+b3+b4+b5+b6 Regards, Peg Exelis VIS Tech Support

Thanks for that, however I have tried that approach and the follow up image I get there my data is no longer visible just a blank output. Previous to summing the bands I have already carried out a band math process to eradicate unnecessary data from my images. What I am wanting to do now is combine all of these images onto one output so they can be represented on top of a land cover image Regards Green

What is the equation you used and what is the data type of the image you are using? You may need to promote your data type. For example, if your data is stored as BYTE, you will need to promote the data type so that the resulting data can have a value greater than 256: float(b1)+float(b3)+float(b3).... The above will produce a floating point output that has a much larger data range.

Thanks again, but unfortunately it is again providing a blank output image. I have tried the float equation and the simple b1+b2+b3 etc equation and neither are working. I am using MODIS data downloaded from NASA reverb which I have then carried out band math on to eradicate data I don't required so have values of 0 or 1 for all the data in my image, where 1 is acceptable and 0 is not. All of my images I have saved as ENVI.img files so have those and hdr files saved, how do I go about finding out how my data is stored e.g. BYTE etc? Regards Green

To find out the data type, you can look at the header information for the data type (Edit ENVI Header) or if using ENVI 5 or 5.1, you can right click to get the Metadata information on a file open in the Data Manager or Layer Manager. Are you sure the data is 'blank' and all 0s? Perhaps it is a display issue that is causing it to look blank. You can calculate statistics on the data to see what the data values and ranges are to confirm. You can also pick a single pixel and look at the values for that pixel in each band and perform a hand calculation to see what value you expect. At this point it may also be a good idea to go to technical support directly for more assistance.