Reference

CRS — Coordinate Reference Systems

How geographic coordinates are projected onto a map. UTM-WGS84 is the most common for satellite imagery deliveries.

WGS84 · GEOGRAPHICequatornear polesquare degrees ≠ square kmUTM · 60 ZONES × 6°10121416182022242628square metresuniform area within zoneEPSGUSECAUTION4326WGS84 lat/lon · storage, interchangeNot equal-area — avoid for distance/area math326NNUTM zone NN · measurement, processingStitch fails across zone boundaries3857Web Mercator · web map tilesDisplay only — area grossly distorted near poles
Fig. 1 Coordinate reference systems (CRS) define how positions on an ellipsoidal Earth map to a flat grid. WGS84 geographic (lat/lon) is universal storage; UTM (60 zones, 6° wide) is the working system for accurate area and distance measurement. Web Mercator is for display only — it distorts area badly near the poles.

A CRS defines how 3D positions on Earth are represented as 2D map coordinates. UTM (Universal Transverse Mercator) divides the world into 60 zones and projects each onto a flat map with minimal local distortion. WGS84 is the global reference ellipsoid most satellite providers use.

Geographic vs projected

Geographic CRS uses latitude/longitude in degrees. Projected CRS (like UTM) uses metres and is suitable for measuring distances and areas. Most satellite imagery is delivered in UTM-WGS84 because it allows direct measurement in metres without further conversion.

What to ask

If your downstream workflow requires a specific CRS (a national grid like British National Grid, NAD83 state plane, or a country-specific projection), ask us to reproject before delivery. Reprojection is included at no cost in our standard pipeline.