The geoid measures mean sea level and gravity. The GRACE and GOCE satellites are providing the most accurate measurements of the geoid to this date.
A vertical datum is a reference surface of zero elevation to which heights are referred to. Datums are used to measure height and depth from mean sea level.
Ellipsoids, survey benchmarks and triangulation – these are the ingredients for geodetic datums. NAD27, NAD83 and WGS84 are common datums in North America.
We can find any location on Earth using latitude and longitude coordinates. And we measure those coordinates with decimal degrees or degrees/minutes/seconds
The Greenwich Meridian (or Prime Meridian) is a zero degrees longitudinal It is the start-point which we measure 180 degrees east and west.
5 Halloween Maps. Almost all cultures recognize spirits aka the dead. So we bring these 5 maps for the dead to get you in the spirit of Halloween.
The best way to represent the Earth is with a globe. But map projections can be awfully useful too. Find out why cartographers use map projections in GIS.
This guide is like your compass – these 33 mapping tips will guide you in the right direction and show you how to create stunning cartographic maps.
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
The World Geodetic System 1984 (WGS84) is the spatial reference system of GPS satellites with an error of less than 2 centimeters to the center of Earth.