2000.10.06 14:44 "RE: Old-style JPEG and HP 9100C Digital Sender", by Ed Grissom
Transparent Value (not a mask)
Yes to both
"No Data" value
It has been pointed out to me that these two (TransparencyValue/NODATAValue) are essentially the same. Graphics Arts folks want transparency whereas Remote Sensing types say "we did not collect data for this point in the grid". Also, when images are warped from one projection to another, it is very likely that there are edge pixels that do not map to anything in the original image and should be recorded as "NO DATA" for this position.