How to structure GIS data for POMCA watershed planning

A POMCA GIS database should preserve the provenance of each input and the relationship among assessment, zoning, measures and monitoring. A folder of final layers can produce maps, but it cannot explain which version supported a decision or how that decision should be updated later.

Colombia's Ministry of Environment adopted the technical guide through Resolution 1907 of 2013 and publishes the technical guide for POMCA formulation. Consult these documents at the official source and check them against the current scope of the process. In a data architecture they guide phases and requirements; they do not authorise copying or redistribution without checking applicable conditions.

Build a source catalogue first

For every dataset, record producer, cutoff, scale or resolution, CRS, licence, coverage, method and internal owner. Distinguish the received source from a derived product. If a geometry is repaired or a land-cover class is changed, retain the connection to the input and describe the transformation.

Organise the inventory by question, not just topic:

• What defines the analysis unit, and in which version?
• Which data support water availability, demand and quality?
• Which layers describe ecosystems, land cover and land use?
• Where are hazards, exposure and events recorded?
• What evidence supports land-use conflict and zoning?
• How are programmes, indicators and intervention areas connected?

This matrix reveals gaps before the team depends on a layer that cannot be cited or updated.

Separate observations, analysis and decisions

A station, sample or observed cover is a source record. An index or overlay is an analytical result. A zoning class is a decision within the process. Keeping these at separate levels allows an analysis to be recalculated without deleting the adopted version.

Use persistent identifiers for hydrographic units, reaches, subzones, measures and indicators. Define domains and geometry rules. Check overlaps, gaps, incompatible dates and units. Maps should declare their intended scale; zooming in does not create detail that was never measured.

Design monitoring during formulation

Each measure needs a location or scope, indicator, baseline, process-defined target, frequency, owner and evidence. If an action cannot honestly be represented as a polygon, use the relevant territorial unit rather than inventing precision. Maintain states such as proposed, adopted, in progress and verified according to project governance.

Hazard and exposure scenarios can connect to GIS for risk management, while keeping a POMCA product distinct from a separate municipal or sectoral study.

Validate one complete chain

Before scaling, take one measure through source, assessment, decision, indicator, update and publication. Confirm that the team can reproduce the map and explain its limits. GeoSAT's GIS consulting for POMCA and watersheds can structure that workflow, but it does not adopt the instrument, replace the competent authority or guarantee approval of a deliverable.