Vertical datum conversion download#

Unlike the earth, it has a smooth, uninterrupted surface.Įllipsoids are defined by their geometric parameters, which include a semimajor axis (the radius of its equator) and semiminor axis (distance from its center to either pole). Like the earth, it’s spherical, but not perfectly so.

(You can check out a more thorough explanation of these topics here, but in short:Ī reference ellipsoid is an approximated, more uniform model of the earth. To understand the purpose horizontal and vertical datums serve, we must first discuss two related concepts: ellipsoids and geoids.

Vertical datum conversion download#

And for a deeper dive into topics related to CRSs and geodesy, you can download our ebook on the subject: Ellipsoids and geoids Read on for a quick explanation of horizontal and vertical datums, how they’re used in surveying, and how they’ve evolved over the years. Because understanding the function of datums is crucial to getting the bigger picture of CRSs, we created this quick primer. In fact, the term “datum” is often used interchangeably with “ geographic coordinate system” (or a type of CRS used for specifying the location of a point on the earth).īut a datum is only one component of a geographic coordinate system-albeit an indispensable one. Of the elements that make up a coordinate reference system (CRS), none are more fundamental than datums.