Agent Guide: arcgis-coordinates-projection

Quick-reference for coordinate systems. Read before reprojecting.

Quick Decision Tree

1. WGS84 ↔ 3857? → webMercatorUtils (sync; no datum check, no pole clamp).
2. Other reprojection? → if (!isLoaded()) await projectOperator.load() then execute.
3. Different datums? → geographicTransformationUtils.getTransformations(in, out, aoi) and pass { geographicTransformation } explicitly.
4. Colombia? → plane coordinates in 9377 (Origen-Nacional), not the legacy zones (3116…).

Setup Checklist

• await projectOperator.load() before execute (otherwise: p is not a function).
• Load the geodetic operators too before using them.
• x = longitude, y = latitude.
• Match SRs before geometry comparisons.
• Use webMercatorUtils for the common pair.
• Track each geometry's spatialReference.

Anti-patterns (one-liner reminders)

• ❌ projectOperator.execute before load().
• ❌ Comparing geometries in different SRs (intersectsOperator returns false, no error).
• ❌ Relabelling a datum instead of transforming it (492 m in Bogotá).
• ❌ Hand-rolled web-mercator math.

Files in This Skill

• SKILL.md / SKILL.es.md — full guides
• references/api-detail.md — SpatialReference / projectOperator / webMercatorUtils
• references/examples.md — reprojection examples
• references/pitfalls.md — extended troubleshooting
• scripts/snippet-project.ts, snippet-webmercator.ts