Performance and Compression Efficiency of Open Spatial Data Formats for CAD–GIS Integration in Underground Mining: An Industrial Case Study

Integrating CAD-based mine maps with GIS through ETL tools requires an intermediate spatial data format suitable for a range of applications. This industrial case study compares GeoJSON, GeoPackage and GML, each uncompressed and in ZIP archives, using production mine workings maps of three underground copper mines of KGHM Polska Miedź S.A. (1,179,967 vector features). The comparison was undertaken to support the enterprise’s internal mine map data integration needs. Eleven operations were timed in FME, GDAL/OGR and QGIS, covering local and network reading and writing as well as interactive display. Uncompressed GeoPackage was the fastest in nine of the eleven operations; in local reading in FME, it required 7.0 s, compared with 48.2 s for GeoJSON and 191.6 s for GML, and it was 24.76% and 39.94% smaller, respectively. ZIP compression reduced file sizes by 90.75–94.68%, with GeoJSON producing the smallest archive. Compression shortened network reading of GeoPackage and network writing of the text-based formats in FME (GeoJSON: from 991 to 172 s), but it slowed local reading and, for GeoPackage, zooming in QGIS (from 9 to 388 s). Working, transport and archival formats should therefore be selected against separate criteria, and format efficiency must be combined with change detection, concurrency control and limited disk operations in the ETL process.