Geodesy Jamaica Datum

Geodesy

University of Technology, Jamaica

Lecture 2
Coordinate Systems and Datums In Jamaica

University of Technology, Jamaica

Overview
• • • • • • • • • • Conventional Terminology Geodetic Coordinate Systems The Concept of Datums Defining a Geodetic Datum The Jamaican Datum GPS Datum Coordinate Transformation Projection to National Grid Summary Exercise

University of Technology, Jamaica

Lesson Objectives
• By the end of this lesson, students should be able to:
– Define a Geodetic Coordinate System – Distinguish between Local and Global Coordinate systems – Identify Transformation Parameters for at least two Caribbean Territories – Transform Coordinates between Datums Using at least 3 different Methods – Project Geodetic Coordinates to a selected National Grid
University of Technology, Jamaica

Where are we now? N180 01’ 03” W76 44’ 39” Are we sure? But, which datum are we using?

University of Technology, Jamaica

Conventional Terminology
• Coordinate Representation
– Geodetic (Lat, Lon and Height) – Cartesian (X, Y and Z) – Map Projection (Eastings and Northings) – Elevations (mainly Orthometric heights)

• Coordinate Reference System
– Definition of the system – Usually require 8 parameters/constants – Essentially, adoption of ellipsoid parameters
University of Technology, Jamaica

Plane ellipse (2D)

Minor axis

Major axis Foci

University of Technology, Jamaica

Ellipsoid is formed by rotating the ellipse about its minor axis Semi-major axis = a b a Semi-minor axis = b Flattening = f = (a-b)/a Eccentricity = e = SQRT(2f-f2 ) e2 = 2f – f2

Reference latitude Reference longitude

University of Technology, Jamaica

Geodetic Ellipsoidal Coordinates
• Size and shape determined by semi-major axis (a), flattening (f) • Latitude – angle btw ellipsoidal equator and the normal • Longitude – angle btw zero meridian and the plane containing the normal & the minor axis
University of Technology, Jamaica

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