EPSG:9377 for energy data: reprojecting with traceability and precision
What to record when transforming energy data to MAGNA-SIRGAS 2018 Origen-Nacional: source CRS, operation, units, controls and final format.
Reprojecting to EPSG:9377 is not the same as assigning a new code to a file. First identify the source data’s actual coordinate reference system; then apply an explicit transformation, review coordinates and extent, and retain evidence of the process. When the source CRS is wrong, output may look valid while being displaced. Checks need to occur before and after conversion to the official format.
Fix the source of truth before transformation
Keep “define” separate from “transform”. Defining a CRS describes existing coordinates; transforming calculates new ones. For UPME deliverables within the current scope, the official register identifies EPSG:9377 and SHP or GDB formats. An intermediate GeoJSON is useful for local geometry inspection, but it is not by itself the required deliverable.
Record the evidence used to identify the source CRS: sidecar file, metadata, supplier specification, known points and coordinate ranges. Then document the transformation operation, library and version, not only the EPSG codes. Test control points distributed across the area, compare relevant distances or areas and verify that the final extent is plausible for Colombia. If a source mixes systems or the origin cannot be established, isolate it as an exception. The history must make the EPSG:9377 result reproducible without guessing how it was obtained.
Recommended sequence
- Verify. Obtain the declared source CRS, epoch, capture method and units from the producer.
- Map. Check ranges, extent and known points before accepting the reported code.
- Prepare. Select the transformation operation and record software, version and parameters.
- Check. Compare control points, lengths, areas and spatial relationships after reprojection.
- Close. Export to the required format and recheck CRS, fields, counts and metadata.
Minimum control evidence
The technical preparation record should retain:
- source CRS supported by evidence.
- recorded transformation operation.
- independent control points.
- review of the final artefact rather than only the in-memory layer.
What the diagnostic cannot promise
Visual proximity on a basemap does not replace numerical controls. Web services may reproject on the fly and hide the stored CRS. Not every difference is an error either: capture accuracy, generalisation and date matter. State tolerances based on use and scale. GeoSAT can diagnose values and geometry, but it does not certify geodetic accuracy or acceptance by an authority.
Review the specialised GeoSAT service to define scope and the related cluster to identify interoperability, environmental or territorial dependencies. This guide is informational; service pages explain evidence, tooling and an appropriate next step without promising an official decision.