Dear colleagues,
I'm working with Grass Gis 6.4.4. and learning with 7.0 (GUI interface). I calculate TOA-reflectance with i.landsat.toar module. But some time I launch the module, the following warning appear.
WARNING! ESUN EVALUATED FROM REFLECTANCE MAXIMUM BAND
My Russian colleagues are sure that I shouldn't pay any attention to this warning as the output TOA-reflectance data is always the same with the data obtained by entering ESUN value for many routine kinds of work. Although they are not sure that it is acceptable for any special image processing, such as DOS atmospheric correction etc. And the problem is that my job is very special without any right for mistake. I have to do many experiments with various image processing to get acceptable results.
And so I need reliable TOA reflectance data.
My question are:
1. Can anyone tell if I can get appropriate TOA-reflectance data without entering Esun value? Can this parameter significantly influence the output data? In what cases?
2. How in i.landsat.toar module I can enter Esun value?
3. Why the warning appear not every time but after the same actions and it depend on certain image?
It might be good to ask this on http://lists.osgeo.org/listinfo/grass-user mailing list.
Thank you,
I didn't think I could ask such question there. If it is possible, I surely ask this on mailing list.
Regards,
Maria
There is a grass-dev mailing list which is dedicated to developers and others who wish to contribute to the development of GRASS GIS in some way, by coding or just by providing feedback. It is also used by people doing advanced things in GRASS GIS such as developing modules in C. The user mailing list (grass-user) is used by anybody who wants some discussion or advice on how to interpret error massages, documentation, fix some problems or solve concrete GIS or remote sensing tasks. You can have a look to the mailing list archive to see what questions are being ask, for example here is link for March: http://lists.osgeo.org/pipermail/grass-user/2015-March/thread.html
- Badges
- Science topic
- Similar topics
- Engineering
- Electrical Engineering
- Signal Processing
- Image Processing