On Fri, 17 Nov 2006, Simon Elliott wrote:
Hi all,
WHen I look at the file attached by HansPeter (HP GRIB.001) it looks fine to
me. The GRIB part can be found after the first 899 bytes. The remaining part
(GRIB to 7777, inclusive) is 803521 bytes long, which is as indicated in octets
9 to 16 of Section 0.
Hi Simon,
First, let me thank you for your time. There's no problem decoding the (HP
GRIB.001) file with my decoder that is 803521 bytes long. The file that was
originally sent was not 803521 bytes, but 804420 bytes long. When the file
was edited, the editor inserted extra bytes into the file. This caused the
decoder to get confused and it could not extract the data. As you know the GRIB
format is very rigid, so one extra byte can change the course of action of the
decoder. There was some confusion about the acquistion of the file and I was
unawared that the file was edited, so I assumed that there was some EUMETSAT
changes in the file. Since the EUMETSAT datasets are very important to our
community, I made an effort to decode the file with the extra bytes. When
debugging, I added some code to accomodate the extra bytes but the decoder
still got confused about the data extraction process. When I got an uncorrupted
file, my decoder work without a problem.
There is one question, the level information is using level 0, is that correct?
First Surface Type : 0 Reserved
First Surface value : 0.0
Second Surface Type : 0 Reserved
Second Surface value : 0.0
I have never run across a model using these values before, can you give some
insight?
Thanks,
Robb...
Here's a dump of the Header information of the file, is there an problem here?
--------------------------------------------------------------------
Header : GRIB2
Discipline : 3 Space products
GRIB Edition : 2
GRIB length : 803521
Originating Center : 254 EUMETSAT Operation Centre
Originating Sub-Center : 0
Significance of Reference Time : 3 Observation time
Reference Time : 2006-01-02T11:45:00Z
Product Status : 1 Operational test products
Product Type : 6 Processed satellite observations
Number of data points : 1530169
Grid Name : 90 Space View Perspective or Orthographic
Grid Shape: 3 Earth oblate spheroid with axes
specified by
producer
Oblate earth major axis: 6378.14
Oblate earth minor axis: 6356.7554
Number of points along parallel: 1237
Number of points along meridian: 1237
Latitude of sub-satellite point: 0.0
Longitude of sub-satellite pt: 0.0
Resolution & Component flags : 0
i direction increment : 1188.0
j direction increment : 1187.0
X-coordinate of sub-satellite : 619.0
Y-coordinate of sub-satellite : 619.0
Scanning mode : 192
Basic angle : 0
Altitude of the camera : 7.4533146E8
X-coordinate of origin : 0.0
Y-coordinate of origin : 0.0
Product Definition : 30 Satellite product
Parameter Category : 1 Quantitative_products
Parameter Name : 2 Cloud_Top_Height
Parameter Units : m
Generating Process Type : 8 Observation
ForecastTime : 0
First Surface Type : 0 Reserved
First Surface value : 0.0
Second Surface Type : 0 Reserved
Second Surface value : 0.0
--------------------------------------------------------------------
Header : GRIB2
Discipline : 3 Space products
GRIB Edition : 2
GRIB length : 803521
Originating Center : 254 EUMETSAT Operation Centre
Originating Sub-Center : 0
Significance of Reference Time : 3 Observation time
Reference Time : 2006-01-02T11:45:00Z
Product Status : 1 Operational test products
Product Type : 6 Processed satellite observations
Number of data points : 1530169
Grid Name : 90 Space View Perspective or Orthographic
Grid Shape: 3 Earth oblate spheroid with axes
specified by
producer
Oblate earth major axis: 6378.14
Oblate earth minor axis: 6356.7554
Number of points along parallel: 1237
Number of points along meridian: 1237
Latitude of sub-satellite point: 0.0
Longitude of sub-satellite pt: 0.0
Resolution & Component flags : 0
i direction increment : 1188.0
j direction increment : 1187.0
X-coordinate of sub-satellite : 619.0
Y-coordinate of sub-satellite : 619.0
Scanning mode : 192
Basic angle : 0
Altitude of the camera : 7.4533146E8
X-coordinate of origin : 0.0
Y-coordinate of origin : 0.0
Product Definition : 30 Satellite product
Parameter Category : 1 Quantitative_products
Parameter Name : 3 Cloud_Top_Height_Quality_Indicator
Parameter Units :
Generating Process Type : 8 Observation
ForecastTime : 0
First Surface Type : 0 Reserved
First Surface value : 0.0
Second Surface Type : 0 Reserved
Second Surface value : 0.0
