convert_to_csv_2d

Overview¶

The convert_to_csv_2d tool is a utility script for converting 2D netCDF or GeoJSON files to a CSV format. It extracts the essential coordinate data (x, y) and includes any associated metadata or attributes.

In this tutorial, we assume yu want to convert a 2D netCDF file (example.nc) or GeoJSON file (example.geojson) from the /sample_files/2d directory to a CSV file.

Steps¶

1. Navigate to the File Directory¶

Change your directory to the location of the 2D netCDF or GeoJSON files:

cd sample_files/2d

2. Run the convert_to_csv_2d Script¶

Use the convert_to_csv_2d script to convert the example.nc or example.geojson file to CSV format:

For a netCDF File:¶

../../src/convert_to_csv_2d.py -i example.nc -o example.csv

For a GeoJSON File:¶

../../src/convert_to_csv_2d.py -i example.geojson -o example.csv

Command Breakdown¶

• -i example.nc or -i example.geojson: Specifies the name of the input file to convert.

• -o example.csv: Specifies the name of the output CSV file.

Note: The output file will contain coordinate columns (x, y) and any additional metadata or attributes from the original file.

3. Verify the Output Files¶

After running the script, you should see the corresponding CSV file in the same directory as your input file.

Example Outputs¶

Input GeoJSON File¶

Input: example.geojson¶

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": { "name": "Feature1", "value": 10 },
      "geometry": {
        "type": "Point",
        "coordinates": [102.0, 0.5]
      }
    },
    {
      "type": "Feature",
      "properties": { "name": "Feature2", "value": 20 },
      "geometry": {
        "type": "LineString",
        "coordinates": [
          [103.0, 1.0],
          [104.0, 2.0]
        ]
      }
    }
  ]
}

Output CSV File¶

Output: example.csv¶

name,value,x,y
Feature1,10,102.0,0.5
Feature2,20,103.0,1.0
Feature2,20,104.0,2.0

Input netCDF File¶

Input: example.nc¶

The netCDF file example.nc is assumed to contain 2D data variables (x, y) along with associated attributes or metadata.

Output CSV File¶

Output: example.csv¶

x,y,temperature,pressure
102.0,0.5,25.6,1013.2
103.0,1.0,26.1,1012.8
104.0,2.0,27.0,1011.5

Notes¶

1. Handling Missing Values:

   • Any missing values in the input file are represented as NaN in the output CSV.

2. Supported Geometry Types (GeoJSON):

   • The script supports Point and LineString geometry types.

   • For multi-point geometries like LineString, each point is represented as a separate row in the CSV.

3. netCDF Data Extraction:

   • The script extracts coordinate data (x, y) and all 2D attributes or variables in the netCDF file.

4. Flexibility:

   • The script dynamically detects the file type (netCDF or GeoJSON) without relying on file extensions.

5. Output Columns:

   • GeoJSON: Includes properties (name, value, etc.) and coordinates (x, y).

   • netCDF: Includes variables and their respective coordinate data (x, y).

Troubleshooting¶

• Ensure that the input file is a valid 2D netCDF or GeoJSON file.

• Check that the /sample_files/2d directory contains the file you want to convert.

• If encountering issues, run the script with the -h option to display the help message:

  ../../src/convert_to_csv_2d.py -h

This guide ensures that you can seamlessly convert 2D netCDF and GeoJSON files to CSV format. For further assistance, feel free to consult the script documentation.