sample_concentration - bruno-beloff/scs_analysis GitHub Wiki
docs > software repositories > scs_analysis > commands > filtering and aggregating data
The sample_concentration utility is used to inject a gas concentration value, based on a given density (micrograms per cubic metre), temperature and pressure (kPa). The reported value is in parts per billion.
Density and temperature must be supplied from the input JSON document. Atmospheric pressure may be supplied from the input JSON document. Alternatively, a pressure estimate may be supplied on the command line. In both cases, pressure should be indicated in kilopascals (kPa). If no pressure value is supplied, the standard pressure of 101.3 kPa is used.
Recognised gases are:
| Gas | Molar mass |
|---|---|
| CO2 | 44.0100 |
| NO | 30.0100 |
| NO2 | 46.0055 |
| O3 | 48.0000 |
| SO2 | 64.0660 |
The path for the node in the output document indicating concentration is based on the path for the node in the input document indicating density. For example, if the input path is SUB-PATH.dns, the output path is SUB-PATH.cnc. If a SUB-PATH.cnc field exists in the input document, it is overwritten.
sample_concentration.py [-v] GAS DENSITY_PATH T_PATH [{P_PATH | -p PRESSURE}]
| Options | |
|---|---|
| --version | show program's version number and exit |
| -h, --help | show this help message and exit |
| -p PRESSURE, --pressure=PRESSURE | assume constant atmospheric pressure in kPA (default 101.3) |
| -v, --verbose | report narrative to stderr |
csv_reader.py joined_2019-02.csv | sample_concentration.py -v NO2 ref.val.NO2.dns praxis.val.sht.tmp
{"rec": "2019-02-12T13:00:00Z", "praxis": {"val": {"NO2": {"weV": 0.300059, "cnc": 23.4, "aeV": 0.302339, "weC": -0.002793}, "sht": {"hmd": 67.6, "tmp": 13.1}}}, "ref": {"val": {"NO2": {"units": "ugm-3", "dns": 51}}}}
{"rec": "2019-02-12T13:00:00Z", "praxis": {"val": {"NO2": {"weV": 0.300059, "cnc": 23.4, "aeV": 0.302339, "weC": -0.002793}, "sht": {"hmd": 67.6, "tmp": 13.1}}}, "ref": {"val": {"NO2": {"units": "ugm-3", "dns": 51, "cnc": 26.0}}}}
scs_core/src/scs_core/gas/gas.py
http://www.apis.ac.uk/unit-conversion