Filter Example¶
This example demonstrates how to:
Read in points using Tracktable’s C++ command line factories
Using ‘required’ option
Using a function object to filter those points
Using a point writer to output those points
The full filter
example source code can be found in the Tracktable source
code distribution in the directory tracktable/Examples
and the example
can be executed by calling the filter
program from the command line provided
that the example is built and it’s location is exposed to the appropriate system path.
Below you will find the execution command for the example as well as the
source files in there entirety for quick reference.
Example Source Files¶
The page listed here contains a direct import of the source code for this example. This is provided for convenience and reference.
Command Line Interface¶
Note
This command is specific to Linux and Mac. Windows machines will have a different command line call.
The command to run the filter
example is as follows.
$ ./filter_time --input=/data/flights.tsv --output=/results/filtered.tsv --start=2013-07-10-00:00:05 --stop=2013-07-10-00:01:05
This command takes an input parameter of a tab separated value or comma seperated value file
formatted as OBJECTID TIMESTAMP LON LAT
, an output parameter tab separated value or comma seperated value
file for the filtered points and start and stop timestamps parameters to use as a filter bounds.
Note
The default delimiter is tab
, if you are using a CSV file
you will need to set the --delimiter
parameter. The default output
is standard out unless a --output
file is specified.
The command line interface contains a --help
option that will display all of the possible
switches for the example.
$ ./filter --help
will display:
--help Print help
--output arg (=-) file to write to (use '-' for stdout),
overridden by 'separate-kmls'
--output arg (=-) file to write to (use '-' for stdout),
overridden by 'separate-kmls'
--start arg timestamp to start at
--stop arg timestamp to stop at
Point Reader:
--input arg (=-) Filename for input (use '-' for standard input)
--real-field arg Field name and column number for a real-valued
point field
--string-field arg Field name and column number for a string point
field
--timestamp-field arg Field name and column number for a timestamp
point field
--object-id-column arg (=0) Column containing object ID for points
--timestamp-column arg (=1) Column containing timestamp for points
--x-column arg (=2) Column containing X / longitude coordinate
--y-column arg (=3) Column containing Y / latitude coordinate
--delimiter arg (= ) Delimiter for fields in input file