Description Usage Arguments Value Author(s) References See Also Examples
Internal function that uses the MODIS SOAP Web Service (see references) getsubset method to download a requested time-series subset of a MODIS product for a given area surrounding many locations. This function is used by the MODISSubsets function, which is the main subset download tool for the user.
1 | GetSubset(Lat, Long, Product, Band, StartDate, EndDate, KmAboveBelow, KmLeftRight)
|
Lat |
Numeric; a decimal degrees latitude in WGS-1984 coordinate system. |
Long |
Numeric; a decimal degrees longitude in WGS-1984 coordinate system. |
Product |
A character string; a product code to request the subset from. The MODIS product table shows all available products and their respective product titles (see references). |
Band |
A character string; a code or vector of codes to retrieve the desired data band(s) within the specified product to be requested. To get a list of the available bands in a product of interest use GetBands(). |
StartDate |
Character; in MODIS date format, listing the date to begin the time-series for each corresponding location. |
EndDate |
Character; in MODIS date format, listing the date to end the time-series for each corresponding location. |
KmAboveBelow |
An integer; the distance, in kilometres, from the centre of the tile of pixels to the top and bottom of the tile. So, if KmAboveBelow=1, the total distance from top to bottom of the tile will be 2km. |
KmLeftRight |
An integer; the distance, in kilometres, from the centre of the tile of pixels to the left and right sides of the tile. So, if KmLeftRight=1, the total distance from side to side of the tile will be 2km. |
A data frame containing: xll=The x coordinate, in the MODIS coordinate system, of the lower left corner of the pixel in which the location data falls. yll=The y coordinate, in the MODIS coordinate system, of the lower left corner of the pixel in which the location data falls. pixelsize=The actual calculated width of the pixels of interest, in metres. nrow=Corresponds to KmAboveBelow argument. ncol=Corresponds to KmLeftRight argument. band=Corresponds to band argument. scale=The number by which raw downloaded data values can be scaled by. Specific to each band. lat=Corresponds to the Lat argument. long=Corresponds to the Long argument. subset=The downloaded data, as a vector of character strings, with length number of time-steps requested, that include data attached to metadata.
This data frame is then passed to MODISSubsets.
Sean Tuck
https://daacmodis.ornl.gov/cgi-bin/MODIS/GLBVIZ_1_Glb/modis_subset_order_global_col5.pl
1 2 3 4 5 6 7 8 | ## Not run:
# dontrun() used because running the example requires internet access,
# and takes over a minute to run.
data(SubsetExample)
GetSubset(Lat=SubsetExample[ ,1], Long=SubsetExample[ ,2], Product="MOD13Q1",
Band="250m_16_days_EVI", StartDate="A2001001", EndDate="A2001025",
KmAboveBelow=0, KmLeftRight=0)
## End(Not run)
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