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Welcome to the 2015 GRIB API: Library and Tools course pages!
.
Tuesday 24 February
09:00 Welcome - Umberto Modigliani
- Lecturers
- Students
09:15 GRIB API Introduction - Shahram Najm
- GRIB editions 1 and 2: structure and differences
- GRIB API design and concepts
10:30 Coffee
11:00 GRIB API: Tools - Carsten Maass
- Introduction to the grib_api command-line tools
- Obtaining information about the grib_api installation with grib_info
Inspecting the content of GRIB files with grib_count, grib_ls and grib_dump
GRIB Tools - Solutions to practicals
Solution to grib_dump practical
1. To view the keys available for GRIB1 and GRIB2 have a look at GRIB API or http://old.ecmwf.int/publications/manuals/grib_api/index.html
2. To use grib_dump to inspect the contents of file1.grib1:
%grib_dump file1.grib1
By using grib_dump on its own and with the various options, (-O, -a, etc), you should find:
• the message is encoded using GRIB edition 1 (editionNumber=1);
• it contains the 2 metre temperature field (shortName=2t, marsParam=167.128);
• the dataDate= 20110225, the dataTime=12 and the forecast step=12;
• the data is on a reduced Gaussian grid (typeOfGrid=reduced_gg) with N=128 (Nj=256);
Alternatively, with grib_dump inspect some templates in the “GRIB_SAMPLES_PATH” directory.
3. For the file file2.grib2
% grib_dump file1.grib2
By using grib_dump on its own and with various options, (-O, -a etc), you should find:
• the message is encoded using GRIB edition 2 - grib_edition=2;
• it contains the temperature field on a specified hight of 2 m above ground (shortName=2t, paramId = 167, discipline = 0, parameterCategory = 0, parameterNumber = 0, typeOfFirstFixedSurface = 103);
• the dataDate=20110225, the dataTime=12 and the forecast step=12;
• the data is on a reduced Gaussian grid (typeOfGrid=reduced_gg) with N=128 (Nj=256);
4. To quickly find the maximum, minimum and average values of the field, look for the computed keys max, min, and average.
For both files you should find:
• maximum = 314.204
• minimum = 222.44
• average = 285.261
Solution to grib_ls practical
1. To list the GRIB messages in msl.grib1
% grib_ls msl.grib1Welcome to the 2015 GRIB API: Library and Tools course pages!
.
Training course time table and course materialTuesday 24 February
09:00 Welcome - Umberto Modigliani
- Lecturers
- Students
09:15 GRIB API Introduction - Shahram Najm
- GRIB editions 1 and 2: structure and differences
- GRIB API design and concepts
10:30 Coffee
11:00 GRIB API: Tools - Carsten Maass
- Introduction to the grib_api command-line tools
- Obtaining information about the grib_api installation with grib_info
Inspecting the content of GRIB files with grib_count, grib_ls and grib_dump
GRIB Tools - Solutions to practicals
Solution to grib_dump practical
1. To view the keys available for GRIB1 and GRIB2 have a look at GRIB API or http://old.ecmwf.int/publications/manuals/grib_api/index.html
2. To use grib_dump to inspect the contents of file1.grib1:
%grib_dump file1.grib1
By using grib_dump on its own and with the various options, (-O, -a, etc), you should find:
• the message is encoded using GRIB edition 1 (editionNumber=1);
• it contains the 2 metre temperature field (shortName=2t, marsParam=167.128);
• the dataDate= 20110225, the dataTime=12 and the forecast step=12;
• the data is on a reduced Gaussian grid (typeOfGrid=reduced_gg) with N=128 (Nj=256);
Alternatively, with grib_dump inspect some templates in the “GRIB_SAMPLES_PATH” directory.
3. For the file file2.grib2
% grib_dump file1.grib2
By using grib_dump on its own and with various options, (-O, -a etc), you should find:
• the message is encoded using GRIB edition 2 - grib_edition=2;
• it contains the temperature field on a specified hight of 2 m above ground (shortName=2t, paramId = 167, discipline = 0, parameterCategory = 0, parameterNumber = 0, typeOfFirstFixedSurface = 103);
• the dataDate=20110225, the dataTime=12 and the forecast step=12;
• the data is on a reduced Gaussian grid (typeOfGrid=reduced_gg) with N=128 (Nj=256);
4. To quickly find the maximum, minimum and average values of the field, look for the computed keys max, min, and average.
For both files you should find:
• maximum = 314.204
• minimum = 222.44
• average = 285.261
Solution to grib_ls practical
1. To list the GRIB messages in msl.grib1
% grib_ls msl.grib1msl.grib1edition centre typeOfLevel level dataDate stepRange dataType shortName packingType gridType1 ecmf surface 0 20110225 0 cf msl grid_simple regular_gg1 ecmf surface 0 20110225 6 cf msl grid_simple regular_gg1 ecmf surface 0 20110225 12 cf msl grid_simple regular_gg1 ecmf surface 0 20110225 18 cf msl grid_simple regular_gg1 ecmf surface 0 20110225 24 cf msl grid_simple regular_gg5 of 5 grib messages in msl.grib15 of 5 total grib messages in 1 files
The file contains mean sea-level pressure (shortName=msl) from the ECMWF EPS control forecast (dataType=cf) for 6-hourly steps from 0 to 24 hours for dataDate=20110225. The messages are encoded in GRIB edition 1.
2. To list the GRIB messages in msl.grib2
% grib_ls msl.grib2
msl.grib2
edition centre date dataType gridType stepRange typeOfLevel level shortName packingType
2 ecmf 20110225 cf regular_gg 0 meanSea 0 msl grid_simple
2 ecmf 20110225 cf regular_gg 6 meanSea 0 msl grid_simple
2 ecmf 20110225 cf regular_gg 12 meanSea 0 msl grid_simple
2 ecmf 20110225 cf regular_gg 18 meanSea 0 msl grid_simple
2 ecmf 20110225 cf regular_gg 24 meanSea 0 msl grid_simple
5 of 5 grib messages in msl.grib2
5 of 5 total grib messages in 1 files
The file also contains mean sea-level pressure (shortName=msl) from the ECMWF EPS control forecast (dataType=cf) for 6-hourly steps from 0 to 24 hours for dataDate=20110225. In this file the messages are encoded in GRIB edition 2.
The lists show the default keys printed by grib_ls for GRIB 1 and GRIB 2.
3. To print the mars keys, use grib_ls -m:
% grib_ls -m msl.grib1
msl.grib1
domain levtype date time step param class type stream expver
g sfc 20110225 0000 0 151.128 od cf enfo 0001
g sfc 20110225 0000 6 151.128 od cf enfo 0001
g sfc 20110225 0000 12 151.128 od cf enfo 0001
g sfc 20110225 0000 18 151.128 od cf enfo 0001
g sfc 20110225 0000 24 151.128 od cf enfo 0001
5 of 5 grib messages in msl.grib1
5 of 5 total grib messages in 1 files
% grib_ls -m msl.grib1
msl.grib2
domain date time expver class type stream step levtype levelist param
g 20110225 0000 0001 od cf enfo 0 sfc 0 151
g 20110225 0000 0001 od cf enfo 6 sfc 0 151
g 20110225 0000 0001 od cf enfo 12 sfc 0 151
g 20110225 0000 0001 od cf enfo 18 sfc 0 151
g 20110225 0000 0001 od cf enfo 24 sfc 0 151
5 of 5 grib messages in msl.grib2
5 of 5 total grib messages in 1 files
4. Output can be printed in descending step order using grib_ls with the -B option. Note it is necessary to use “step:l” here as step has a default type of ‘string’.
% grib_ls -B "step:l desc" msl.grib1
edition centre typeOfLevel level dataDate stepRange dataType shortName packingType gridType
1 ecmf surface 0 20110225 24 cf msl grid_simple regular_gg
1 ecmf surface 0 20110225 18 cf msl grid_simple regular_gg
1 ecmf surface 0 20110225 12 cf msl grid_simple regular_gg
1 ecmf surface 0 20110225 6 cf msl grid_simple regular_gg
1 ecmf surface 0 20110225 0 cf msl grid_simple regular_gg
% grib_ls -B "step:l desc" msl.grib2
edition centre date dataType gridType stepRange typeOfLevel level shortName packingType
2 ecmf 20110225 cf regular_gg 24 meanSea 0 msl grid_simple
2 ecmf 20110225 cf regular_gg 18 meanSea 0 msl grid_simple
2 ecmf 20110225 cf regular_gg 12 meanSea 0 msl grid_simple
2 ecmf 20110225 cf regular_gg 6 meanSea 0 msl grid_simple
2 ecmf 20110225 cf regular_gg 0 meanSea 0 msl grid_simple
5. To specify a set of keys to print, use the -p option:
% grib_ls -p centre,dataDate,stepRange,typeOfLevel,shortName msl.grib1
msl.grib1
centre dataDate stepRange typeOfLevel shortName
ecmf 20110225 0 surface msl
ecmf 20110225 6 surface msl
ecmf 20110225 12 surface msl
ecmf 20110225 18 surface msl
ecmf 20110225 24 surface msl
5 of 5 grib messages in msl.grib1
5 of 5 total grib messages in 1 files
Using the "key:l" for centre and levelType prints these keys as their integer values rather than strings:
% grib_ls -p centre:l,dataDate,stepRange,levelType:l,shortName,paramId msl.grib1
msl.grib1
centre dataDate stepRange levelType shortName paramId
98 20110225 0 1 msl 151
98 20110225 6 1 msl 151
98 20110225 12 1 msl 151
98 20110225 18 1 msl 151
98 20110225 24 1 msl 151
5 of 5 grib messages in msl.grib1
5 of 5 total grib messages in 1 files
Similarly for msl.grib2:
% grib_ls -p centre:l,dataDate,stepRange,levelType:l,shortName,paramId msl.grib2
msl.grib2
centre dataDate stepRange levelType shortName paramId
98 20110225 0 101 msl 151
98 20110225 6 101 msl 151
98 20110225 12 101 msl 151
98 20110225 18 101 msl 151
98 20110225 24 101 msl 151
5 of 5 grib messages in msl.grib2
5 of 5 total grib messages in 1 files
Solution to grib_ls -l practical
1. To list the nearest points to ECMWF (Lat 51.42 N, Lon 0.95 W) use
% grib_ls -l 51.42,-0.95 msl.grib1
…
5 of 5 total grib messages in 1 files
Input Point: latitude=51.42 longitude=-0.95
Grid Point chosen #3 index=17199 latitude=51.62 longitude=359.10 distance=22.57 (Km)
Other grid Points
- 1 - index=17599 latitude=50.72 longitude=359.10 distance=77.54 (Km)
- 2 - index=17598 latitude=50.72 longitude=358.20 distance=97.59 (Km)
- 3 - index=17199 latitude=51.62 longitude=359.10 distance=22.57 (Km)
- 4 - index=17198 latitude=51.62 longitude=358.20 distance=62.87 (Km)
Note we specify the longitude of 0.95 W with -0.95 !
The nearest grid point is at latitude=51.62 longitude=359.10 (=0.9 W) and is 22.57 km from ECMWF.
2. To output only the forecast step and MSLP value at the nearest grid point use:
% grib_ls -l 51.42,-0.95,1 -p stepRange msl.grib1
msl.grib1
stepRange value
0 102527
6 102365
12 102456
18 102289
24 101862
5 of 5 grib messages in msl.grib1
5 of 5 total grib messages in 1 files
Input Point: latitude=51.42 longitude=-0.95
Grid Point chosen #3 index=17199 latitude=51.62 longitude=359.10 distance=22.57 (Km)
Other grid Points
- 1 - index=17599 latitude=50.72 longitude=359.10 distance=77.54 (Km)
- 2 - index=17598 latitude=50.72 longitude=358.20 distance=97.59 (Km)
- 3 - index=17199 latitude=51.62 longitude=359.10 distance=22.57 (Km)
- 4 - index=17198 latitude=51.62 longitude=358.20 distance=62.87 (Km)
Note it is necessary to specify MODE=1 in order to print the value of the nearest grid point only.
To output the values at the four grid points nearest to ECMWF, use MODE=4 which is the default:
% grib_ls -l 51.42,-0.95 -p stepRange msl.grib1
msl.grib1
stepRange value1 value2 value3 value4
0 102674 102663 102527 102501
6 102532 102516 102365 102333
12 102633 102585 102456 102426
18 102444 102390 102289 102259
24 102057 101959 101862 101760
5 of 5 grib messages in msl.grib1
5 of 5 total grib messages in 1 files
Input Point: latitude=51.42 longitude=-0.95
Grid Point chosen #3 index=17199 latitude=51.62 longitude=359.10 distance=22.57 (Km)
Other grid Points
- 1 - index=17599 latitude=50.72 longitude=359.10 distance=77.54 (Km)
- 2 - index=17598 latitude=50.72 longitude=358.20 distance=97.59 (Km)
- 3 - index=17199 latitude=51.62 longitude=359.10 distance=22.57 (Km)
- 4 - index=17198 latitude=51.62 longitude=358.20 distance=62.87 (Km)
3. To specify the land-sea mask, use:
% grib_ls -l 51.42,-0.95,1,lsm.grib1 -p stepRange msl.grib1
msl.grib1
stepRange value
0 102527
6 102365
12 102456
18 102289
24 101862
5 of 5 grib messages in msl.grib1
5 of 5 total grib messages in 1 files
Input Point: latitude=51.42 longitude=-0.95
Grid Point chosen #3 index=17199 latitude=51.62 longitude=359.10 distance=22.57 (Km)
Mask values:
- 1 - index=17599 latitude=50.72 longitude=359.10 distance=77.54 (Km) value=0.00
- 2 - index=17598 latitude=50.72 longitude=358.20 distance=97.59 (Km) value=1.00
- 3 - index=17199 latitude=51.62 longitude=359.10 distance=22.57 (Km) value=1.00
- 4 - index=17198 latitude=51.62 longitude=358.20 distance=62.87 (Km) value=1.00
Here the mask value at the end of the line showing the four nearest grid points indicates which are land points: Land points have mask ≥ 0.5; sea points have mask<0.5.
12:15 GRIB API: Keys - Shahram Najm
- Coded and computed keys
- The namespace
- Examples of keys
13:00 Lunch
14:00 GRIB API: Tools - Paul Dando
- Comparing the content of GRIB messages with grib_compare
- Printing data values with grib_get_data
- Using grib_get
15:30 Coffee
16:00 GRIB API: Tools - Paul Dando
- Copying GRIB messages with grib_copy
- Making simple modifications to the GRIB header information with grib_set
16:55 Questionnaire/Feedback
17:00 Cocktails
Wednesday 25 February
09:00 GRIB API: Fortran, C, Python APIs - Dominique Lucas, Xavi Abellan, Cristian Simarro
- Overview of the API
- Using the API functions for decoding with Fortran, C and Python
- Practicals
10:30 Coffee
11:00 GRIB API: Fortran, C, Python APIs (continued) - Dominique Lucas, Xavi Abellan, Cristian Simarro
- Practicals
13:00 Lunch
14:00 GRIB API: Advanced tools - Paul Dando
- Basic features of grib_filter
- Conversion from GRIB to NetCDF with grib_to_netcdf
15:30 Coffee
16:00 GRIB API: General practicals
16:55 Questionnaire/Feedback
17:00 End
Thursday 26 February
09:00 GRIB API: Fortran, C, python APIs - Advanced features - Dominique Lucas, Xavi Abellan, Cristian Simarro
- Use of the indexing routines
- Encoding GRIB messages and using GRIB samples
- Practicals
10:30 Coffee
11:00 GRIB API: Fortran, C, python APIs - Advanced features (continued) - Dominique Lucas, Xavi Abellan, Cristian Simarro
- Practicals
13:00 Lunch
14:00 GRIB API: Python interface - Xavi Abellan
- A short introduction to Python and its use at ECMWF
- The Python interface to grib_api for decoding, encoding and indexed access to GRIB messages
15:30 Coffee
16:00 GRIB API: Advanced topics I - Shahram Najm
- Simple packing
- Constant fields
- Bitmap fields
- Multi fields
16:55 Questionnaire/Feedback
17:00 End
Friday 27 February
09:00 GRIB API: Advanced topics II - Shahram Najm
- Parameter database
- Conversion from GRIB 1 to GRIB 2
10:30 Coffee
11:00 GRIB API: Advanced topics III - Shahram Najm
- Local adaptation - how to define your own local parameters
12:15 Quiz
12:55 Questionnaire/Feedback
13:00 End of module COM GRIB
Recommended reading
- Lecture notes:GRIB API: Library and tools training course 2014
Go to the training home page
What is happeningBlog posts to follow
Complete the surveySurvey to follow
msl.grib1
edition centre typeOfLevel level dataDate stepRange dataType shortName packingType gridType
1 ecmf surface 0 20110225 0 cf msl grid_simple regular_gg
1 ecmf surface 0 20110225 6 cf msl grid_simple regular_gg
1 ecmf surface 0 20110225 12 cf msl grid_simple regular_gg
1 ecmf surface 0 20110225 18 cf msl grid_simple regular_gg
1 ecmf surface 0 20110225 24 cf msl grid_simple regular_gg
5 of 5 grib messages in msl.grib1
5 of 5 total grib messages in 1 files
The file contains mean sea-level pressure (shortName=msl) from the ECMWF EPS control forecast (dataType=cf) for 6-hourly steps from 0 to 24 hours for dataDate=20110225. The messages are encoded in GRIB edition 1.
2. To list the GRIB messages in msl.grib2
% grib_ls msl.grib2
msl.grib2
edition centre date dataType gridType stepRange typeOfLevel level shortName packingType
2 ecmf 20110225 cf regular_gg 0 meanSea 0 msl grid_simple
2 ecmf 20110225 cf regular_gg 6 meanSea 0 msl grid_simple
2 ecmf 20110225 cf regular_gg 12 meanSea 0 msl grid_simple
2 ecmf 20110225 cf regular_gg 18 meanSea 0 msl grid_simple
2 ecmf 20110225 cf regular_gg 24 meanSea 0 msl grid_simple
5 of 5 grib messages in msl.grib2
5 of 5 total grib messages in 1 files
The file also contains mean sea-level pressure (shortName=msl) from the ECMWF EPS control forecast (dataType=cf) for 6-hourly steps from 0 to 24 hours for dataDate=20110225. In this file the messages are encoded in GRIB edition 2.
The lists show the default keys printed by grib_ls for GRIB 1 and GRIB 2.
3. To print the mars keys, use grib_ls -m:
% grib_ls -m msl.grib1
msl.grib1
domain levtype date time step param class type stream expver
g sfc 20110225 0000 0 151.128 od cf enfo 0001
g sfc 20110225 0000 6 151.128 od cf enfo 0001
g sfc 20110225 0000 12 151.128 od cf enfo 0001
g sfc 20110225 0000 18 151.128 od cf enfo 0001
g sfc 20110225 0000 24 151.128 od cf enfo 0001
5 of 5 grib messages in msl.grib1
5 of 5 total grib messages in 1 files
% grib_ls -m msl.grib1
msl.grib2
domain date time expver class type stream step levtype levelist param
g 20110225 0000 0001 od cf enfo 0 sfc 0 151
g 20110225 0000 0001 od cf enfo 6 sfc 0 151
g 20110225 0000 0001 od cf enfo 12 sfc 0 151
g 20110225 0000 0001 od cf enfo 18 sfc 0 151
g 20110225 0000 0001 od cf enfo 24 sfc 0 151
5 of 5 grib messages in msl.grib2
5 of 5 total grib messages in 1 files
4. Output can be printed in descending step order using grib_ls with the -B option. Note it is necessary to use “step:l” here as step has a default type of ‘string’.
% grib_ls -B "step:l desc" msl.grib1
edition centre typeOfLevel level dataDate stepRange dataType shortName packingType gridType
1 ecmf surface 0 20110225 24 cf msl grid_simple regular_gg
1 ecmf surface 0 20110225 18 cf msl grid_simple regular_gg
1 ecmf surface 0 20110225 12 cf msl grid_simple regular_gg
1 ecmf surface 0 20110225 6 cf msl grid_simple regular_gg
1 ecmf surface 0 20110225 0 cf msl grid_simple regular_gg
% grib_ls -B "step:l desc" msl.grib2
edition centre date dataType gridType stepRange typeOfLevel level shortName packingType
2 ecmf 20110225 cf regular_gg 24 meanSea 0 msl grid_simple
2 ecmf 20110225 cf regular_gg 18 meanSea 0 msl grid_simple
2 ecmf 20110225 cf regular_gg 12 meanSea 0 msl grid_simple
2 ecmf 20110225 cf regular_gg 6 meanSea 0 msl grid_simple
2 ecmf 20110225 cf regular_gg 0 meanSea 0 msl grid_simple
5. To specify a set of keys to print, use the -p option:
% grib_ls -p centre,dataDate,stepRange,typeOfLevel,shortName msl.grib1
msl.grib1
centre dataDate stepRange typeOfLevel shortName
ecmf 20110225 0 surface msl
ecmf 20110225 6 surface msl
ecmf 20110225 12 surface msl
ecmf 20110225 18 surface msl
ecmf 20110225 24 surface msl
5 of 5 grib messages in msl.grib1
5 of 5 total grib messages in 1 files
Using the "key:l" for centre and levelType prints these keys as their integer values rather than strings:
% grib_ls -p centre:l,dataDate,stepRange,levelType:l,shortName,paramId msl.grib1
msl.grib1
centre dataDate stepRange levelType shortName paramId
98 20110225 0 1 msl 151
98 20110225 6 1 msl 151
98 20110225 12 1 msl 151
98 20110225 18 1 msl 151
98 20110225 24 1 msl 151
5 of 5 grib messages in msl.grib1
5 of 5 total grib messages in 1 files
Similarly for msl.grib2:
% grib_ls -p centre:l,dataDate,stepRange,levelType:l,shortName,paramId msl.grib2
msl.grib2
centre dataDate stepRange levelType shortName paramId
98 20110225 0 101 msl 151
98 20110225 6 101 msl 151
98 20110225 12 101 msl 151
98 20110225 18 101 msl 151
98 20110225 24 101 msl 151
5 of 5 grib messages in msl.grib2
5 of 5 total grib messages in 1 files
Solution to grib_ls -l practical
1. To list the nearest points to ECMWF (Lat 51.42 N, Lon 0.95 W) use
% grib_ls -l 51.42,-0.95 msl.grib1
…
5 of 5 total grib messages in 1 files
Input Point: latitude=51.42 longitude=-0.95
Grid Point chosen #3 index=17199 latitude=51.62 longitude=359.10 distance=22.57 (Km)
Other grid Points
- 1 - index=17599 latitude=50.72 longitude=359.10 distance=77.54 (Km)
- 2 - index=17598 latitude=50.72 longitude=358.20 distance=97.59 (Km)
- 3 - index=17199 latitude=51.62 longitude=359.10 distance=22.57 (Km)
- 4 - index=17198 latitude=51.62 longitude=358.20 distance=62.87 (Km)
Note we specify the longitude of 0.95 W with -0.95 !
The nearest grid point is at latitude=51.62 longitude=359.10 (=0.9 W) and is 22.57 km from ECMWF.
2. To output only the forecast step and MSLP value at the nearest grid point use:
% grib_ls -l 51.42,-0.95,1 -p stepRange msl.grib1
msl.grib1
stepRange value
0 102527
6 102365
12 102456
18 102289
24 101862
5 of 5 grib messages in msl.grib1
5 of 5 total grib messages in 1 files
Input Point: latitude=51.42 longitude=-0.95
Grid Point chosen #3 index=17199 latitude=51.62 longitude=359.10 distance=22.57 (Km)
Other grid Points
- 1 - index=17599 latitude=50.72 longitude=359.10 distance=77.54 (Km)
- 2 - index=17598 latitude=50.72 longitude=358.20 distance=97.59 (Km)
- 3 - index=17199 latitude=51.62 longitude=359.10 distance=22.57 (Km)
- 4 - index=17198 latitude=51.62 longitude=358.20 distance=62.87 (Km)
Note it is necessary to specify MODE=1 in order to print the value of the nearest grid point only.
To output the values at the four grid points nearest to ECMWF, use MODE=4 which is the default:
% grib_ls -l 51.42,-0.95 -p stepRange msl.grib1
msl.grib1
stepRange value1 value2 value3 value4
0 102674 102663 102527 102501
6 102532 102516 102365 102333
12 102633 102585 102456 102426
18 102444 102390 102289 102259
24 102057 101959 101862 101760
5 of 5 grib messages in msl.grib1
5 of 5 total grib messages in 1 files
Input Point: latitude=51.42 longitude=-0.95
Grid Point chosen #3 index=17199 latitude=51.62 longitude=359.10 distance=22.57 (Km)
Other grid Points
- 1 - index=17599 latitude=50.72 longitude=359.10 distance=77.54 (Km)
- 2 - index=17598 latitude=50.72 longitude=358.20 distance=97.59 (Km)
- 3 - index=17199 latitude=51.62 longitude=359.10 distance=22.57 (Km)
- 4 - index=17198 latitude=51.62 longitude=358.20 distance=62.87 (Km)
3. To specify the land-sea mask, use:
% grib_ls -l 51.42,-0.95,1,lsm.grib1 -p stepRange msl.grib1
msl.grib1
stepRange value
0 102527
6 102365
12 102456
18 102289
24 101862
5 of 5 grib messages in msl.grib1
5 of 5 total grib messages in 1 files
Input Point: latitude=51.42 longitude=-0.95
Grid Point chosen #3 index=17199 latitude=51.62 longitude=359.10 distance=22.57 (Km)
Mask values:
- 1 - index=17599 latitude=50.72 longitude=359.10 distance=77.54 (Km) value=0.00
- 2 - index=17598 latitude=50.72 longitude=358.20 distance=97.59 (Km) value=1.00
- 3 - index=17199 latitude=51.62 longitude=359.10 distance=22.57 (Km) value=1.00
- 4 - index=17198 latitude=51.62 longitude=358.20 distance=62.87 (Km) value=1.00
Here the mask value at the end of the line showing the four nearest grid points indicates which are land points: Land points have mask ≥ 0.5; sea points have mask<0.5.
12:15 GRIB API: Keys - Shahram Najm
- Coded and computed keys
- The namespace
- Examples of keys
13:00 Lunch
14:00 GRIB API: Tools - Paul Dando
- Comparing the content of GRIB messages with grib_compare
- Printing data values with grib_get_data
- Using grib_get
15:30 Coffee
16:00 GRIB API: Tools - Paul Dando
- Copying GRIB messages with grib_copy
- Making simple modifications to the GRIB header information with grib_set
16:55 Questionnaire/Feedback
17:00 Cocktails
Wednesday 25 February
09:00 GRIB API: Fortran, C, Python APIs - Dominique Lucas, Xavi Abellan, Cristian Simarro
- Overview of the API
- Using the API functions for decoding with Fortran, C and Python
- Practicals
10:30 Coffee
11:00 GRIB API: Fortran, C, Python APIs (continued) - Dominique Lucas, Xavi Abellan, Cristian Simarro
- Practicals
13:00 Lunch
14:00 GRIB API: Advanced tools - Paul Dando
- Basic features of grib_filter
- Conversion from GRIB to NetCDF with grib_to_netcdf
15:30 Coffee
16:00 GRIB API: General practicals
16:55 Questionnaire/Feedback
17:00 End
Thursday 26 February
09:00 GRIB API: Fortran, C, python APIs - Advanced features - Dominique Lucas, Xavi Abellan, Cristian Simarro
- Use of the indexing routines
- Encoding GRIB messages and using GRIB samples
- Practicals
10:30 Coffee
11:00 GRIB API: Fortran, C, python APIs - Advanced features (continued) - Dominique Lucas, Xavi Abellan, Cristian Simarro
- Practicals
13:00 Lunch
14:00 GRIB API: Python interface - Xavi Abellan
- A short introduction to Python and its use at ECMWF
- The Python interface to grib_api for decoding, encoding and indexed access to GRIB messages
15:30 Coffee
16:00 GRIB API: Advanced topics I - Shahram Najm
- Simple packing
- Constant fields
- Bitmap fields
- Multi fields
16:55 Questionnaire/Feedback
17:00 End
Friday 27 February
09:00 GRIB API: Advanced topics II - Shahram Najm
- Parameter database
- Conversion from GRIB 1 to GRIB 2
10:30 Coffee
11:00 GRIB API: Advanced topics III - Shahram Najm
- Local adaptation - how to define your own local parameters
12:15 Quiz
12:55 Questionnaire/Feedback
13:00 End of module COM GRIB
Recommended reading
- Lecture notes:GRIB API: Library and tools training course 2014
Go to the training home page
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