Home » Coordinate Systems

# Coordinate Systems

## What Is the Web Mercator Projection?

The Web Mercator projection uses a modified version of the Mercator projection and has become a default map projection for web mapping.

## Where is the Central Meridian?

The central meridian is the center line of longitude for projection systems. Projected coordinate systems often use it as a reference point for a x-origin.

## Latitude, Longitude and Coordinate System Grids

Latitude lines run east-west, are parallel and go from -90 to +90. Longitude lines run north-south, converge at the poles and are from -180 to +180.

## The State Plane Coordinate System (SPCS)

The State Plane Coordinate System divides the United States into 124 zones to locate any point with a high level of accuracy (one part in 10,000).

## How Universal Transverse Mercator (UTM) Works

Universal Transverse Mercator (UTM) segments the Earth into 60 zones (each UTM zone is 6‎°) and projects each zone with an upright cylinder of its own.

Ellipsoids, survey benchmarks and triangulation – these are the ingredients for geodetic datums. NAD27, NAD83 and WGS84 are common datums in North America.

## Degrees/Minutes/Seconds (DMS) vs Decimal Degrees (DD)

We can find any location on Earth using latitude and longitude coordinates. And we measure those coordinates with decimal degrees or degrees/minutes/seconds

## Greenwich Meridian (Prime Meridian)

The Greenwich Meridian (or Prime Meridian) is a zero degrees longitudinal It is the start-point which we measure 180 degrees east and west.

## NAD83 – We’re Not in Kansas Anymore

North American Datum of 1983 (NAD83) is 2-meters from geocentric and uses thousands of monuments with triangulation to create a reference frame for Earth

## World Geodetic System (WGS84)

The World Geodetic System 1984 (WGS84) is a spatial reference system of GPS satellites with an error of less than 2 cm to the center of Earth.