readVAC: Read ASCII files containing satellite for specific situations...
In steingod/R-osisaf: Useful functions for handling EUMETSAT Ocean and Sea Ice SAF data
Description
Usage
Arguments
Details
Value
Author(s)
References
See Also
Description
Read ASCII files containing satellite data for specific situations.
These files have usually been created for specific classes.
Usage
1
readVAC(filename)
Arguments
filename
full path and filename to read
Details
VAC = Visible Avhrr Collocation
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Output file format:
-------------------
The VAC result files are in ASCII format. There are no header
data in the files. The files are organized in fixed formatted
coloumns divided by at least one blank.
There are 22 columns with the following content:
1: Index. Same number indicates same collocation object
2: Main class object classification (see README_classes.txt)
3: Sub class object classification (see README_classes.txt)
4: Satellite name
5: Pixel latitude
6: Pixel longitude
7: Year
8: Month
9: Day
10: Hour
11: Minute
12: Channel 1 albedo
13: Channel 2 albedo
14: Channel 3B brightness temperature
15: Channel 4 brightness temperature
16: Channel 5 brightness temperature
17: Channel 3A albedo
18: Satellite zenith angle
19: Solar zenith angle
20: Relative azimuth angle
21: Elevation of pixel (in meters)
22: Surface/land use class
Albedo values are given in 0-100
Negative channel values indicate undefined values.
Elevation and surface class are from the USGS data base.
Elevation is in meters. Surface classes as follows:
USGS Land Use/Land Cover System Legend (Modified Level 2)
Value Code Description
1 100 Urban and Built-Up Land
2 211 Dryland Cropland and Pasture
3 212 Irrigated Cropland and Pasture
4 213 Mixed Dryland/Irrigated Cropland and Pasture
5 280 Cropland/Grassland Mosaic
6 290 Cropland/Woodland Mosaic
7 311 Grassland
8 321 Shrubland
9 330 Mixed Shrubland/Grassland
10 332 Savanna
11 411 Deciduous Broadleaf Forest
12 412 Deciduous Needleleaf Forest
13 421 Evergreen Broadleaf Forest
14 422 Evergreen Needleleaf Forest
15 430 Mixed Forest
16 500 Water Bodies
17 620 Herbaceous Wetland
18 610 Wooded Wetland
19 770 Barren or Sparsely Vegetated
20 820 Herbaceous Tundra
21 810 Wooded Tundra
22 850 Mixed Tundra
23 830 Bare Ground Tundra
24 900 Snow or Ice
99 Interrupted Areas (Goodes Homolosine Projection)
100 Missing Data
Remarks:
--------
The index value is used in the collocation process. These numbers are
unique for each object in the original collocation files. When passage
collocation files are concatinated, these values are no longer unique.
But the index value can still be used to separate different
collocation objects as two following objects on the files will never
have equal indexes. This is because there must always be at least two
objects on a collocation input file.
Classes:
--------
There are 12 main classes that are used in VAC. These are:
SNOW - Cloud free land areas covered by snow.
UNCSN - Uncertain snow, possible snow free land (cloud free).
LAND - Cloud free land areas with NO snow.
ICE - Cloud free sea areas covered with ice and/or snow.
WETIC - Cloud free wet sea ice/glacier ice.
UNCIC - Uncertain sea ice, possible open sea (cloud free).
SEA - Cloud free sea areas with NO snow or ice.
CLOUD - Land or sea areas covered by clouds.
MIXSL - A mixture of cloud free snow and land with no snow.
MIXMO - A mixture of mountain, flat and shadow, most probably with snow.
MIXSI - A mixture of cloud free sea ice, possible with some open sea.
SHAD - Shadow, from cloud over cloud, land or snow.
For a list of the subclasses available, please refer to the
documentation provided by Steinar Eastwood s.eastwood@met.no.
Value
readVAC use read.table to access the external data, thus data
are returned as a data.frame using relatively self explaining
names on the columns according to the description given above.
Author(s)
Øystein Godøy o.godoy@met.no
References
The VAC system is developed and maintained by Steinar Eastwood
s.eastwood@met.no. Please contact him for further information
on the system.
See Also
plotVAChist
steingod/R-osisaf documentation built on May 30, 2019, 2:32 p.m.
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Description Usage Arguments Details Value Author(s) References See Also
Description
Read ASCII files containing satellite data for specific situations. These files have usually been created for specific classes.
Usage
1 | readVAC(filename)
|
Arguments
filename |
full path and filename to read |
Details
VAC = Visible Avhrr Collocation
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 | Output file format:
-------------------
The VAC result files are in ASCII format. There are no header
data in the files. The files are organized in fixed formatted
coloumns divided by at least one blank.
There are 22 columns with the following content:
1: Index. Same number indicates same collocation object
2: Main class object classification (see README_classes.txt)
3: Sub class object classification (see README_classes.txt)
4: Satellite name
5: Pixel latitude
6: Pixel longitude
7: Year
8: Month
9: Day
10: Hour
11: Minute
12: Channel 1 albedo
13: Channel 2 albedo
14: Channel 3B brightness temperature
15: Channel 4 brightness temperature
16: Channel 5 brightness temperature
17: Channel 3A albedo
18: Satellite zenith angle
19: Solar zenith angle
20: Relative azimuth angle
21: Elevation of pixel (in meters)
22: Surface/land use class
Albedo values are given in 0-100
Negative channel values indicate undefined values.
Elevation and surface class are from the USGS data base.
Elevation is in meters. Surface classes as follows:
USGS Land Use/Land Cover System Legend (Modified Level 2)
Value Code Description
1 100 Urban and Built-Up Land
2 211 Dryland Cropland and Pasture
3 212 Irrigated Cropland and Pasture
4 213 Mixed Dryland/Irrigated Cropland and Pasture
5 280 Cropland/Grassland Mosaic
6 290 Cropland/Woodland Mosaic
7 311 Grassland
8 321 Shrubland
9 330 Mixed Shrubland/Grassland
10 332 Savanna
11 411 Deciduous Broadleaf Forest
12 412 Deciduous Needleleaf Forest
13 421 Evergreen Broadleaf Forest
14 422 Evergreen Needleleaf Forest
15 430 Mixed Forest
16 500 Water Bodies
17 620 Herbaceous Wetland
18 610 Wooded Wetland
19 770 Barren or Sparsely Vegetated
20 820 Herbaceous Tundra
21 810 Wooded Tundra
22 850 Mixed Tundra
23 830 Bare Ground Tundra
24 900 Snow or Ice
99 Interrupted Areas (Goodes Homolosine Projection)
100 Missing Data
Remarks:
--------
The index value is used in the collocation process. These numbers are
unique for each object in the original collocation files. When passage
collocation files are concatinated, these values are no longer unique.
But the index value can still be used to separate different
collocation objects as two following objects on the files will never
have equal indexes. This is because there must always be at least two
objects on a collocation input file.
Classes:
--------
There are 12 main classes that are used in VAC. These are:
SNOW - Cloud free land areas covered by snow.
UNCSN - Uncertain snow, possible snow free land (cloud free).
LAND - Cloud free land areas with NO snow.
ICE - Cloud free sea areas covered with ice and/or snow.
WETIC - Cloud free wet sea ice/glacier ice.
UNCIC - Uncertain sea ice, possible open sea (cloud free).
SEA - Cloud free sea areas with NO snow or ice.
CLOUD - Land or sea areas covered by clouds.
MIXSL - A mixture of cloud free snow and land with no snow.
MIXMO - A mixture of mountain, flat and shadow, most probably with snow.
MIXSI - A mixture of cloud free sea ice, possible with some open sea.
SHAD - Shadow, from cloud over cloud, land or snow.
|
For a list of the subclasses available, please refer to the documentation provided by Steinar Eastwood s.eastwood@met.no.
Value
readVAC use read.table to access the external data, thus data are returned as a data.frame using relatively self explaining names on the columns according to the description given above.
Author(s)
Øystein Godøy o.godoy@met.no
References
The VAC system is developed and maintained by Steinar Eastwood s.eastwood@met.no. Please contact him for further information on the system.
See Also
plotVAChist
R Package Documentation
Browse R Packages
We want your feedback!
Note that we can't provide technical support on individual packages. You should contact the package authors for that.
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