NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
Current content can be found at unidata.ucar.edu.
To learn about what's going on, see About the Archive Site.
Hi Gilles, I apologize for the slow response to your emails. We are in the middle of hosting the triennial Unidata User's Workshop, and the time I have for attending to support inquiries has been limited... re: > me again, sorry, > > I custom-made an inversed color table from the Gempak color table I > normally use to enhance IR imagery (it is not perfect but it is OK) > > If you know anyway a way to inverse the scale (if it is in IDV it is even > better), that would be really appreciated, In the IDV all you have to do is to invert the range that the enhancement is mapping to. This can be done by right clicking on a color bar for an image that has been displayed and selecting Change Range, or you can create a new color table from an existing one in the Color Table Editor. In the color table editor, simply swap the low and high data values in the Range entry boxes and then save the enhancement under a different name whose name will remind you that the values have been inverted. re: > For time of operation and corresponding satellite number I gathered some > information so it should be fine (see attached screen shot for time of op) OK. Just to make sure that I am understanding your comment "so it should be fine": Are you saying that you now have enough information to allow you to get archived images from GOES-East and GOES-West datasets for the time periods you are interested in? re: > I also tried to download data from the CLASS website (that allowed me to > see which GOES number I should use), > > I attached the imagery for a specific date in 2011 in McIDAS data format > (at low resolution) FYI: The image you downloaded from CLASS is 10-bit imagery. The images that are distributed in the Unidata-Wisconsin (IDD feedtype UNIWISC) datastream are 8-bit. re: > Once uploaded in IDV, I noticed that the scale is inversed compared to what > I normally download from adde.ucar.edu server That is correct. The color table is being applied to the range of values in the image, and because the image is infrared, the higher values pixels are warmer temperatures (higher pixel values -> more blackbody radiation -> warmer). re: > I think I remember during a workshop I assisted at UNIDATA that you > mentioned something about the scale in which satellite imagery comes as > original format and how to inverse it but I cannot find it in my notes > What is the way to inverse the scale? (or should I design a specific scale > equivalent to the one I normally use in IDV (I am pretty sure there is a > way...frustrating to not remember)) As I noted above, you can simply edit the color table (which I typically refer to as an enhancement since that is called in McIDAS-X) and change the low value of the range to what the high is and the high value to what the low was. re: > I would not be surprised that the data in the UNIWISC IDD Datastream will > come the same way than the CLASS data, so I think that I have to solve > that detail anyway. The default in the IDV is to recognize images that have had their raw, 10-bit counts mapped into brightness values and automatically flip the application of the enhancement. This is so that the display of cold cloud tops in IR imagery looks like clouds (meaning bright white). Please let me know if the above was understandable. Cheers, Tom -- **************************************************************************** Unidata User Support UCAR Unidata Program (303) 497-8642 P.O. Box 3000 address@hidden Boulder, CO 80307 ---------------------------------------------------------------------------- Unidata HomePage http://www.unidata.ucar.edu **************************************************************************** Ticket Details =================== Ticket ID: SXB-674928 Department: Support Datastream Priority: Normal Status: Closed