netCDF to color GEOTIFF

[Andrea MARELLI]

Hi Alaric,

I've spent 2 weeks trying to display maps from netcdf files and now, with
Norman Barker's help, I can do it.

You don't need to convert into GeoTiff, but you can open directly from
NetCDF.
Try to open the mapfile below with this URL:
http://myhost/cgi-bin/mapserv?map=test.map&mode=map&layer=sst
&map_projection=init=epsg:4326 

ATTENTION!!!: you must force the projection in the URL

##########  MAP FILE ##############

MAP
  NAME "test"
  EXTENT  -20 22 45 75
  SHAPEPATH "/data"
  IMAGETYPE PNG24
  SIZE 740 602
  UNITS dd
  DEBUG on

PROJECTION
      "proj=latlong"
      "init=epsg:4326"
END

LAYER
   NAME "sst"
   STATUS ON
   TYPE RASTER
   DUMP TRUE
   DATA "sst.nc"      #Your NetCDF file. It MUST be CF compliant!!!!!!
    PROJECTION
      "proj=latlong"
      "init=epsg:4326"
    END
    PROCESSING "SCALE=-10,40"
    PROCESSING "SCALE_BUCKETS=50"
   CLASS
     NAME "30"
     EXPRESSION ([pixel] >= 30)
     COLOR 79 8 8
   END
   CLASS
     NAME ""
     EXPRESSION ([pixel] >= 29 and [pixel] < 30)
     COLOR 104 8 8
   END
   CLASS
     NAME "28"
     EXPRESSION ([pixel] >= 28 and [pixel] < 29)
     COLOR 176 8 8
   END
   CLASS
     NAME ""
     EXPRESSION ([pixel] >= 27 and [pixel] < 28)
     COLOR 200 8 8
   END
    CLASS
     NAME "26"
     EXPRESSION ([pixel] >= 26 and [pixel] < 27)
     COLOR 224 64 8
   END
   CLASS
     NAME ""
     EXPRESSION ([pixel] >= 25 and [pixel] < 26)
     COLOR 224 112 8
   END
   CLASS
     NAME "24"
     EXPRESSION ([pixel] >= 24 and [pixel] < 25)
     COLOR 224 160 8
   END
   CLASS
     NAME ""
     EXPRESSION ([pixel] >= 23 and [pixel] < 24)
     COLOR 224 208 8
   END
   CLASS
     NAME "22"
     EXPRESSION ([pixel] >= 22 and [pixel] < 23)
     COLOR 232 232 8
   END
   CLASS
     NAME ""
     EXPRESSION ([pixel] >= 21 and [pixel] < 22)
     COLOR 160 224 8
   END
   CLASS
     NAME "20"
     EXPRESSION ([pixel] >= 20 and [pixel] < 21)
     COLOR 112 208 8
   END
   CLASS
     NAME ""
     EXPRESSION ([pixel] >= 19 and [pixel] < 20)
     COLOR 72 184 8
   END
   CLASS
     NAME "18"
     EXPRESSION ([pixel] >= 18 and [pixel] < 19)
     COLOR 56 152 8
   END
   CLASS
     NAME ""
     EXPRESSION ([pixel] >= 17 and [pixel] < 18)
     COLOR 8 136 8
   END
   CLASS
     NAME "16"
     EXPRESSION ([pixel] >= 16 and [pixel] < 17)
     COLOR 8 128 80
   END
   CLASS
     NAME ""
     EXPRESSION ([pixel] >= 15 and [pixel] < 16)
     COLOR 8 144 80
   END
   CLASS
     NAME "14"
     EXPRESSION ([pixel] >= 14 and [pixel] < 15)
     COLOR 8 160 80
   END
   CLASS
     NAME ""
     EXPRESSION ([pixel] >= 13 and [pixel] < 14)
     COLOR 8 184 112
   END
   CLASS
     NAME "12"
     EXPRESSION ([pixel] >= 12 and [pixel] < 13)
     COLOR 8 224 112
   END
   CLASS
     NAME ""
     EXPRESSION ([pixel] >= 11 and [pixel] < 12)
     COLOR 8 232 200
   END
    CLASS
     NAME "10"
     EXPRESSION ([pixel] >= 10 and [pixel] < 11)
     COLOR 8 232 232
   END
   CLASS
     NAME ""
     EXPRESSION ([pixel] >= 9 and [pixel] < 10)
     COLOR 8 200 200
   END
   CLASS
     NAME "8"
     EXPRESSION ([pixel] >= 8 and [pixel] < 9)
     COLOR 8 168 168
   END
   CLASS
     NAME ""
     EXPRESSION ([pixel] >= 7 and [pixel] < 8)
     COLOR 8 136 160
   END
    CLASS
     NAME "6"
     EXPRESSION ([pixel] >= 6 and [pixel] < 7)
     COLOR 8 104 152
   END
   CLASS
     NAME ""
     EXPRESSION ([pixel] >= 5 and [pixel] < 6)
     COLOR 8 96 120
   END
  CLASS
     NAME "4"
     EXPRESSION ([pixel] >= 4 and [pixel] < 5)
     COLOR 8 56 104
   END
   CLASS
     NAME ""
     EXPRESSION ([pixel] >= 3 and [pixel] < 4)
     COLOR 8 32 120
   END
   CLASS
     NAME "2"
     EXPRESSION ([pixel] >= 2 and [pixel] < 3)
     COLOR 8 8 176
   END
   CLASS
     NAME ""
     EXPRESSION ([pixel] >= 1 and [pixel] < 2)
     COLOR 8 8 240
   END
   CLASS
     NAME "0"
     EXPRESSION ([pixel] >= 0 and [pixel] < 1)
   COLOR 144 8 240
   END
   CLASS
     NAME ""
     EXPRESSION ([pixel] < 0)
     COLOR 144 0 111
   END

END

TEMPLATEPATTERN 'template*'

WEB
    TEMPLATE  'template.php'
    IMAGEPATH 'temp/'
    IMAGEURL  'http://myhost/temp/'
    LOG '/temp/mapserver.log'
END

END  

############# END OF MAPFILE #################

Hope it will works!!

Bye, 
Andrea




-----Original Message-----
From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On
Behalf Of Alaric S. Haag
Sent: Tuesday, 29 November, 2005 20:02
To: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: [UMN_MAPSERVER-USERS] netCDF to color GEOTIFF

Hello all, (my first post...)

I have been working with mapserver and the FWTools package, etc, for a few
weeks. I hope this question isn't too far off the mapserver-sepcific realm.
And please forgive the length of the post, just trying to be thorough.

Short question: How are people generating COLOR GeoTIFFs?

My goal is to render satellite images (spec. sea-surface temps) as a raster
layer IN COLOR. I can get the data to a netCDF, or even HDF. With
"gdal_translate" I can get a grayscale GeoTIFF that mapserver displays fine.
Ideally, I'd like to render essentially with a "value palette" (ala GMT .cpt
files), that is, render value (ranges) with assigned color (ranges). I'm
imagining others need similar capabilities, so I'm hoping someone can point
me in the right direction.

I thought I was getting close by pulling the GeoTIFF into OpenEV and
"reclassifying" and exporting, but the result seems to be an 32-bit RGBA
that mapserver can't (?) display. I have "mogrify'd" that down to 256
colors, but get grayscale back ("ColorInterp=Gray" is there a way to change
that?)

A few caveats:
 - I'd like to avoid "commercial" solns like ERDAS, or Arc...
 - I'd love a command-line solution that I can "cron"...

Am I just looking at a GDAL library coding project?

Thanks for any feedback!
Alaric