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 quite powerful 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 config will be output to the commandline. If you want it to be written to a file, use the -o option with the path to the vrt file to write.

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

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Install

Summary of the operations:

1. You will need the GDAL/OGR library and its python bindings. It is not listed in the requirements.txt file, because the installation depends on having the proper libraries already installed on your computer
2. Then installing the ogr2vrt-simple app will be quite easy

More in details:

1. Install the GDAL/OGR library and its python bindings (and build dependencies)

On a classic linux environment, using pip as the installation tool for your python packages, you will need to install quite a few build dependencies. Alternatively, you can use conda for a simpler installation (conda installs in advance a lot of stuff, but indeed makes the install less complicated afterward). Choose one of those:

On a classic linux environment,

• on debian/ubuntu:

  sudo apt update && sudo apt install gdal-bin libgdal-dev python3-dev python3-venv build-essential
  

• on fedora:

  sudo dnf makecache --refresh && sudo dnf install gdal gdal-devel gcc gcc-c++ python3-devel
  

• install GDAL package using

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

Alternative: on a conda environment:

conda install -c conda-forge gdal

(should be enough, then install ogr2vrt_simple)

2. Install the ogr2vrt-simple app

Create a virtual env and install the ogr2vrt-simple app:

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

Install on Windows, using OSGeo4W

OSGeo4W provides handy support for installing several useful libraries. It will make it easy to install this package. You will have to launch the OSGeo4W setup tool (either from a fresh new install, or look into the OSGeo4W menu, for a Setup entry). After a few steps, you can select the packages you want to install. You will have to make sure you are installing

• gdal

• gdal-devel

• python3-core

• python3-pip

• python3-devel

• python3-gdal

• Go on and install them if necessary.

Then open the OSGeo4W console and type pip install ogr2vrt_simple. It should install without trouble. If there are troubles, read carefully the error message, you might have missed one package to install using OSGeo4W setup tool.

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)

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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