Roberto Garcia,MSc wrote:
Hi, tks for the answers.
According to my gdainfo output file attached, can anyone tell me what
element could be a CLASSITEM?
Roberto,
In MapServer you always classify rasters based on the item [pixel] but
you do not need to explicitly state a classitem.
This is a relatively simple example of raster classification.
LAYER
NAME grid1
TYPE raster
STATUS default
DATA data/float.tif
CLASS
NAME "red"
EXPRESSION ([pixel] < -3)
COLOR 255 0 0
END
CLASS
NAME "green"
EXPRESSION ([pixel] >= -3 and [pixel] < 3)
COLOR 0 255 0
END
CLASS
NAME "blue"
EXPRESSION ([pixel] >= 3)
COLOR 0 0 255
END
END
I can see my grib using Grads but what tool do I use to translate
individual bands into GeoTIFF?
You can use gdal_translate to extract particular bands from a grib file
as a geotiff (or all the bands). For instance, the following would
extract band 3 (total precipitation):
gdal_translate -b 3 T126L28.grb total_precip.tif
Converting the data on-the-fly to an image is the right way to work?
Having MapServer access the grib file on the fly rather than depending
on pre-translated extracts will reduce data duplication and may help
avoid confusion about what is up to date. However, it is possible that
there will be a performance penalty for extracting directly from GRIB.
If so, it may not be significant enough to matter to you.
What are the problems with Apache if I do not do so?
I don't see how either approach relates to Apache. It is a
data management and possibly performance issue with MapServer.
Best regards,
--
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up | Frank Warmerdam, [email protected]
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush | Geospatial Programmer for Rent
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