# harpcollocate

Find pairs of measurements that match in time and geolocation for two sets of HARP compliant netCDF files.

Usage:
harpcollocate [options] <path-a> <path-b> <outputpath>
Find matching sample pairs between two datasets of HARP files.
The path for a dataset can be either a single file or a directory
containing files. The results will be written as a comma separated
value (csv) file to the provided output path.
If a directory is specified then all files (recursively) from that
directory are used for a dataset.
If a file is a .pth file then the file paths from that text file
(one per line) are used. These file paths can be absolute or
relative and can point to files, directories, or other .pth files.

Options:
-d '<diffvariable> <value> [unit]'
Specifies a collocation criterium.
Only include pairs where the absolute difference between the
values of the given variable for dataset A and B are
less/equal than the given value.
There is a special variable name 'point_distance' to indicate
the earth surface distance between lat/lon points of A and B.
Examples:
-d 'datetime 3 [h]'
-d 'point_distance 10 [km]'
Criteria on azimuth angles, longitude, and wind direction
will be automatically mapped to [0..180] degrees.
--area-intersects
Specifies that latitude/longitude polygon areas of A and B
must overlap
--point-in-area-xy
Specifies that latitude/longitude points from dataset A must
fall in polygon areas of dataset B
--point-in-area-yx
Specifies that latitude/longitude points from dataset B must
fall in polygon areas of dataset A
-nx <diffvariable>
Filter collocation pairs such that for each sample from
dataset A only the nearest sample from dataset B (using the
given variable as difference) is kept
-ny <diffvariable>
Filter collocation pairs such that for each sample from
dataset B only the neareset sample from dataset A is kept.
-oa, --options-a <option list>
List of options to pass to the ingestion module for ingesting
products from the first dataset.
Only applicable if the input product is not in HARP format.
Options are separated by semi-colons. Each option consists
of an <option name>=<value> pair. An option list needs to be
provided as a single expression.
-ob, --options-b <option list>
List of options to pass to the ingestion module for ingesting
products from the second dataset (see above).
-aa, --operations-a <operation list>
List of operations to apply to each product of the first
dataset before collocating.
An operation list needs to be provided as a single expression.
See the 'operations' section of the HARP documentation for
more details.
-ab, --operations-b <operation list>
List of operations to apply to each product of the second
dataset before collocating (see above).
The order in which -nx and -ny are provided determines the order in
which the nearest filters are executed.
When '[unit]' is not specified, the unit of the variable of the
first file from dataset A will be used.

harpcollocate --resample [options] <inputpath> [<outputpath>]
Filter an existing collocation result file by selecting only nearest
samples.

Options:
-nx <diffvariable>
Filter collocation pairs such that for each sample from
dataset A only the nearest sample from dataset B (using the
given variable as difference) is kept
-ny <diffvariable>
Filter collocation pairs such that for each sample from
dataset B only the neareset sample from dataset A is kept.
The order in which -nx and -ny are provided determines the order in
which the nearest filters are executed.

harpcollocate --update <inputpath> <datasetpath> [<outputpath>]
Update an existing collocation result file by checking the
measurements in the given dataset and only keeping pairs
for which measurements still exist

harpcollocate -h, --help
Show help (this text).

harpcollocate -v, --version
Print the version number of HARP and exit.