Use this "Special value replace",you can see the blog:http://hi.baidu.com/dyqwr...fefd71a4a90a79b.html Sorry that it was in chinese,while you can see the pictures.

Sorry, I can't find the download link of that sav file. Would it be possible to upload it to the code library? This little functionality would sure benefit others. Mike

Setting the data ignore value will not cause ENVI to display the file any differently. The data ignore value in the header is only used in certain programmatic processes. These ***** values are typically some very small value such as 1^-32. It can happen if you export a file from ArcGIS which uses the 'nodata' concept to a format that does not use this concept (such as TIFF or ENVI format). A better way to handle it is to create a mask of these values in ENVI and then apply the mask to the dataset. If you know the dynamic range of the dataset, then you can generate a mask based on band data values of less than 0 (or whatever is the lowest value of your actual data). Then apply the mask to the data. Now when you open your file, the data should be stretched and displayed appropriately.

Hi MariM, This sure makes sense with the mask, but it would be nice if there were some functionality (a sav file or something) that does all that in one step. For example, just 'replace' any of these 'special' values with a desired value. The sav file mentioned in the link seems to be doing something similar. Since many ENVI users are using outputs from ArcGIS and the two software packages are integrated in certain ways, this additional functionality would be quite beneficial. It sounds fairly simple and straightforward to me but not as simple unfortunately for me just to create this kind of tool. :) Cheers, Mike

he has to study chinese first