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[McIDAS #MHL-637032]: question about imgremap

Hi Ying,

> As you know, I'm using "imgremap" to project NEXRCOMRP data to GeoTIFF image.

Yes, I have been conversing with Yi about attempts of converting the 4 km 
total precipitation composite to GeoTIFFs.

>The current output projection is Rectilinear. To me, common
>long/lat projection is preferred.

In McIDAS, RECTilinear is a generic Lat,Lon grid.  The PRO=RECT keyword of
IMGREMAP will create a Lat,Lon grid where the increments in latitude and
longitude are fixed and equal.

> I tried MERC, it returns "imgremap.k: Navigation type MERC not supported".

There is something wrong here.  I just did an IMGREMAP of the 4km NTP composite
into a MERCator projection, and it worked as expected:


Beginning Image Data transfer, bytes= 889004
IMGREMAP: transformations complete ... begin data move
Transferring AREA data outbound, bytes= 308128

The image was remapped as hoped/expected and displays with no errors/problems.

> And so do other projection keywords.

It sounds like there may be something wrong with your IMGERMAP binary.

> Is it possible to map the image into projections other than RECT?

Yes, IMGREMAP supports a variety of output projection types:

  PRO=DEST | use the navigation of ddataset (def)
     =LAMB slat1 slat2 slon | Lambert Conformal, standard latitude
                              and standard longitude (slat1 def=30,
                              slat2 def=50, slon def=center longitude)
     =MERC slat | Mercator projection and standard latitude (slat def=0)
     =MOLL slon | Mollweide projection and standard longitude (slon def=0)
     =PS slat slon | Polar Stereographic projection, standard latitude
                     and standard longitude
                     (slat def=60, slon def=center longitude)
     =RADAR rot | Radar projection and rotation angle (rot def=0)
     =RECT | Rectilinear projection
     =SIN | Sinusoidal Equal Area projection
     =TANC slat slon | Tangent Cone projection, standard latitude and
                       standard longitude (slat def=30 if center latitude
                       is in northern hemisphere, -30 if center latitude
                       in southern hemisphere; slon def=center longitude)

The question is why your McIDAS installation is not behaving correctly.
Is this the same machine that Yi allowed me to login to? (unidata.scs.gmu.edu)
If yes, I could login and take a look for you.

Also, I previously advised Yi that the filing of the composite radar images
from the IDD FNEXRAD feed should be organized so that there were fewer images
in output directories.  The reason I advised this change was the ADDE server
was spending inordinates amount of time creating lists of the products
(the server has to open each file to determine if it is of the correct
type and get the date, time, etc.) that are used in the selection of the most
recent image.  The ADDE server code that does the searching/indexing is based
loosely on Unix 'ls', and I noted that one is no longer able to do an 'ls -alt'
of files in your output directories.

In reflecting on the advice I gave (which I still strongly recommend), I
forgot to include that the v2005b version of Unidata McIDAS-X has a code
modification that allows one to specify search of files from "TODAY"
only.  This code might be useful if you feel that you must keep all files
in a single output directory.

> Thanks a lot for your help!

No worries.


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Ticket Details
Ticket ID: MHL-637032
Department: Support McIDAS
Priority: Normal
Status: Open

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