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MARS/Dissemination
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The bitmap option is currently disabled: requirements that currently use bitmap will remain unchanged but can no longer "validate", if Member States need such requirements modified please contact data.services@ecmwf.int until further notice. |
Specifies a Unix filename containing a bitmap definition.
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specifies a UNIX filename containing a bitmap definition in the format defined in appendix 1 of the Dissemination manual.
The bitmap specification is that defined for dissemination purposes in appendix 3 of ECMWF Meteorological Bulletin M3.1: "The dissemination of ECMWF products to Member States", D.Jokic. revision 3 9/97.
The specification is a bitmap definition as described below. The specification is an ASCII text description of a rectangular area bitmap; the specification is held in a Unix file. The bitmap specification takes the form of a set of command-like definitions containing the following:
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END, a stand-alone directive ending the specification.
The following example illustrates the use of the directives above. First the dissemination requirements:
DIS,COUNTRY=EC,TYPE=FC,LEVT=PL,LEVE=500,STEP=240,FORM=GRIB,PARA=GH,REPR=LL,GRID=0.5/0.5,AREA=4.5/0.0/0.0/4.5,
BITMAP=”ECM_001.BITMAP”
The bitmap specification is contained in a separate file, ECM_001.BITMAP
, in the same directory as the file containing the dissemination requirements. It contains the followingFor example:
SPEC,SIZE=10:10,VALUES=OFF, POINTS=01:03-08/10, 03:02-04/07-09, 04:02/03/08/09, 06:0, 07:01-03/08-10, 09:01-10 END Givesand gives the following bitmap: 0 0 1 1 1 1 1 1 0 1 0 0 1 1 1 1 1 1 0 1 0 1 1 1 0 0 1 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 0 0 1 1 1 1 1 1 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
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title | Dissemination |
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For Dissemination
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Notes:
- Within POINTS, values for rows remain defined until new values are given. Thus, in the example above:
- row 2 is the same as row 1
- row 5 is the same as row 4
- row 8 is the same as row 7
- row 10 is the same as row 9
- The definition of row 6 simply indicates that no points are to be switched from the preset value defined in VALUES.
- If VALUES=ON had been coded, the values in the bitmap would all be reversed, thus:
1 1 0 0 0 0 0 0 1 0
1 1 0 0 0 0 0 0 1 0
1 0 0 0 1 1 0 0 0 1
1 0 0 1 1 1 1 0 0 1
1 0 0 1 1 1 1 0 0 1
1 1 1 1 1 1 1 1 1 1
0 0 0 1 1 1 1 0 0 0
0 0 0 1 1 1 1 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 - Member States may define a number of bitmaps in this way; it is suggested that, at least initially, this number be kept below about 20.
- The same bitmap may be used for different areas, provided the areas conform with one another (i.e. have the same number of rows and columns).
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