McIDAS User's Guide
Version 2019.1
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This keyword specifies whether to request the expanded stretch option with image data. The keyword can also be specified as MCS= (as well as MCSTRETCH=).
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MCSTRETCH= |
EXP |
requests use of the expanded stretch option to increase the detail shown in specific visible, water vapor and short-wave infrared imagery when displayed with IMGDISP or copied to a 1-byte Area file using commands like IMGCOPY with STYPE=VISR or IMGREMAP; this option is available in McIDAS-X versions 2017.2 and later, and requires that the image matches one of the satellite and band combinations in the file MCSTRETCH.TXT (run command SEE MCSTRETCH.TXT to view the file) |
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ORIG |
requests use of the original stretch option that was used in all McIDAS-X versions prior to 2017.2; see the file MCSTRETCH.TXT for the ranges used in both the ORIG and EXP options |
The default (if you don't specify this keyword) is to use the method set in the MCSTRETCH environment variable; if it is not set, EXP is assumed. So unless you set the environment variable to MCSTRETCH=ORIG or specify it as a keyword in your IMG* command, the expanded stretch option is used. Likewise, if you change the environment variable setting to MCSTRETCH=ORIG you must specify keyword MCSTRETCH=EXP in your IMG* command to request the expanded stretch option. See Setting the Expanded Stretch Option for more information.
Below are two examples.
IMGDISP GOES16/CONUS BAND=9 MCSTRETCH=EXP
This entry displays band 9 of image GOES16/CONUS while also requesting use of the expanded stretch option. The satellite and band combination matches an entry in the MCSTRETCH.TXT file so if GOES16/CONUS is a local file or is on a server running McIDAS-X 2017.2 or later it is displayed using the expanded stretch option to provide more detail in both the colder and warmer temperatures of this water vapor band. If you replace MCSTRETCH=EXP with MCSTRETCH=ORIG the image is displayed using the original stretch option so it appears the same as it would if displayed in McIDAS-X 2017.1 or earlier.
IMGCOPY HIMAWARI/FD LOCAL/HIM8 BAND=3 STYPE=VISR MCS=EXP
This entry copies band 3 of image HIMAWARI/FD to local dataset LOCAL/HIM8 while also requesting use of the expanded stretch option. The satellite and band combination matches an entry in the MCSTRETCH.TXT file so if HIMAWARI/FD is a local file or is on a server running McIDAS-X 2017.2 or later it is copied using the expanded stretch option to provide more detail in the higher reflectances by expanding the range of those data values over a larger range of 8-bit brightness values. If you replace MCS=EXP with MCS=ORIG the image is copied using the original stretch option so the output Area file has the same data values as it would if IMGCOPYed in McIDAS-X 2017.1 or earlier.
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