kirra-docs

Coordinate System

This page explains how Kirra handles spatial coordinates, bearings, inclinations, and elevations.

Coordinate Axes

Kirra uses UTM-style real-world coordinates:

Axis	Direction
X	East-West (meters east)
Y	North-South (meters north)
Z	Elevation (meters altitude)

Canvas Display

The Kirra canvas uses:

Y-up is North (+ve)
Y-down is South (-ve)
West is X (-ve)
East is X (+ve)

Data values can be very large (e.g., UTM coordinates). Kirra translates coordinates based on the data centroid for display.

Bearing Convention

Bearing is measured clockwise from North:

Bearing	Direction
0°	North
90°	East
180°	South
270°	West

Hole Angle vs. Dip (Mast Angle)

Convention	Vertical	Horizontal
Hole Angle	0° = vertical (straight down)	90° = horizontal
Dip (Mast Angle)	90° = vertical	0° = horizontal

Note: Other systems use different conventions. For example, Surpac uses -90 for vertical down. Always verify your source data when importing.

3D Rendering

The Three.js 3D view uses a local origin offset from the data centroid. This avoids floating-point precision issues when working with large UTM values. Z elevations are never transformed or scaled.