ogr2vrt-simple 0.2.4

Generate a simple VRT file for data transformations

ogr2vrt simple

Generate a simple VRT file from an OGR-compatible dataset

Python package

This is mostly a python package, destined to be used by other applications. By itself, it is quite limited. However, we provide a small CLI tool that acts as a commandline VRT generator.

Command line interface

Generate a VRT file from an OGR-compatible source. The result is to be considered as a "kickoff" VRT file, to refine according to your desires but it will save you some time.

It mostly targets and was tested with spreadsheet data (xls, xslx, ods, csv) but actually should work with most data sources supported by the OGR drivers

Are currently detected:

• the datasource path
• for each layer (depending on the source, there might be one or more layers):
  • the layer name
  • for each field in this layer
    • name
    • type if available (defaults to string)
    • width (precision) if available

By default, the VRT file will be generated alongside the source file, extension .vrt

Features

• Support file as datasource
• Support plain URL as datasource:
  • E.g. https://www.data.gouv.fr/fr/datasets/r/c53cd4d4-4623-4772-9b8c-bc72a9cdf4c2
  • Autodetects the file format if provided in the headers
  • Supports streaming service (e.g. https://www.data.gouv.fr/fr/datasets/r/d22ba593-90a4-4725-977c-095d1f654d28)
  • find path to dataset inside an archive e.g. https://open-data.s3.fr-par.scw.cloud/bdnb_millesime_2022-10-d/millesime_2022-10-d_dep59/open_data_millesime_2022-10-d_dep59_gpkg.zip)
  • determine if needs to download the file as a first step or can use vsicurl functions

Does not support (yet):

• non-UTF-8 csv files

---

Install

• You will need the GDAL/OGR library. It is not listed in the requirements.txt file, because the installation depends on having the proper libraries already installed on your computer.

  The simplest way:

  • install gdal, libgdal-dev, python3-dev packages on your computer
  • install GDAL package using

  pip install GDAL==$(gdal-config --version)
  

• Create a virtual env and install the app

python3 -m venv .venv
source .venv/bin/activate
pip install ogr2vrt-simple

Use the CLI

Once installed, you will have the ogr2vrt_cli command available. For now, it is limited to only one sub-command, generate-vrt:

# Get help
ogr2vrt_cli generate-vrt --help

# Extract VRT from a remote resource
ogr2vrt_cli generate-vrt https://raw.githubusercontent.com/OSGeo/gdal/master/autotest/ogr/data/shp/poly.zip

# Works also on a API remote source:
ogr2vrt_cli generate-vrt -d 'https://data.statistiques.developpement-durable.gouv.fr/dido/api/v1/datafiles/37dd7056-6c4d-44e0-a720-32d4064f9a26/csv?millesime=2023-05&withColumnName=true&withColumnDescription=true&withColumnUnit=true&orderBy=-COMMUNE_CODE&columns=COMMUNE_CODE,COMMUNE_LIBELLE,CLASSE_VEHICULE,CATEGORIE_VEHICULE,CARBURANT,CRITAIR,PARC_2011,PARC_2012,PARC_2013,PARC_2014,PARC_2015,PARC_2016,PARC_2017,PARC_2018,PARC_2019,PARC_2020,PARC_2021,PARC_2022&COMMUNE_CODE=contains%3A09241'

Note: as in the example above, if you are tapping into a remote URL that has special characters in it (e.g. parenthesis), you will have to surround the URL with quotes or escape the characters (this is a shell issue, not a python issue, but an issue that needs to be taken care of anyway)

---

Develop

Compatibility

python >=3.8

Some effort was done to support python 3.8+, but if possible, we would advise to use a more recent one (3.10 or above)

Using poetry

This is now the recommended way

• Install poetry
• Install the dependencies: poetry install
• Run the script:

# Install the dependencies: 
poetry install
#activate the environment
poetry shell 
# You have to install the GDAL library using pip, it doesn't seem to work with poetry directly
pip install GDAL==$(gdal-config --version)

cd ogr2vrt_simple/
python3 cli.py generate-vrt --help

Simply using pip

This should still work.

Create a virtual env and install the requirements

python3 -m venv .venv
source .venv/bin/activate
pip install GDAL==$(gdal-config --version)
pip install -r requirements.txt

You will need the GDAL/OGR library. See above in the install section

Run it

cd ogr2vrt_simple/
# Generate VRT file for a local file (zipped shapefile)
python3 cli.py generate-vrt  https://raw.githubusercontent.com/OSGeo/gdal/master/autotest/ogr/data/shp/poly.zip

# Generate VRT file for a remote CSV resource
python3 cli.py generate-vrt  --with_vsicurl https://www.data.gouv.fr/fr/datasets/r/c53cd4d4-4623-4772-9b8c-bc72a9cdf4c2

List options:

python3 cli.py generate-vrt  --help

Build

Use Poetry to build this script:

# Build
poetry build

# install 
poetry install

# test it
ogr2vrt_cli --help

# Publish it to test-pypi
poetry publish -r test-pypi
# ... or to pypi
poetry publish