Convert GML to CSV

Understanding GML and CSV file formats

GML (Geography Markup Language) is an XML-based format designed for expressing geographical features. It is widely used in GIS (Geographic Information Systems) to store spatial data, such as points, lines, and polygons, along with their attributes.

CSV (Comma-Separated Values) is a simple, widely supported text format for storing tabular data. Each line in a CSV file represents a row, with columns separated by commas. CSV files are easy to import into spreadsheets and databases.

Why convert GML to CSV?

Converting GML to CSV is useful when you need to analyze or visualize spatial attribute data in spreadsheet applications like Microsoft Excel or Google Sheets, or when importing data into databases that do not natively support GML.

How to convert GML to CSV

The conversion process involves extracting attribute data from the GML file and saving it in a tabular CSV format. Spatial coordinates can also be included as columns in the CSV file.

Best software for GML to CSV conversion

QGIS is a powerful, free, and open-source GIS application that supports both GML and CSV formats. To convert GML to CSV in QGIS:

1. Open QGIS and go to Layer → Add Layer → Add Vector Layer.
2. Select your GML file and click Add.
3. Right-click the loaded layer in the Layers panel and choose Export → Save Features As....
4. In the Format dropdown, select CSV.
5. Choose the output file location and configure the fields as needed.
6. Click OK to export the data to CSV.

Other tools like GDAL/OGR (using the ogr2ogr command-line utility) can also perform this conversion efficiently:

ogr2ogr -f CSV output.csv input.gml

Tips for successful conversion

• Ensure your GML file is valid and well-formed before conversion.
• Check the resulting CSV for correct attribute mapping and coordinate formatting.
• If your GML contains complex geometries, consider exporting geometry as WKT (Well-Known Text) in the CSV.