TABLE OF CONTENTS Spatial data deals with location, shapes, and the relationships among features (topology). Site civil drawings, survey drawings, and architectural drawings are examples of spatial data normally compiled with computer-aided design and drafting (CADD) technology. Accuracies are typically depicted in relative terms for example, boundary surveys relative to survey corners for which the geographic coordinates may be unknown in an absolute sense. Pairs of x-y coordinates may be referenced to an arbitrary origin, and accuracies are typically relative for example, estimated as n parts per million of the distance surveyed from one point to the next. The curvature of the earth is often a negligible factor, and the rules of plane geometry typically apply.
Geospatial data refers to spatial data for which geographic coordinates are known in an absolute sense, that is, the spatial dataset is georeferenced to true ground coordinates. The curvature of the earth is important, and the rules of spherical geometry typically apply. Positioning is relative to geodetic data, using control surveys having geodetic network accuracy, rather than local accuracy relative to an arbitrary origin. Geospatial data is georeferenced as 2-D or 3-D coordinates of points on, above, or below a mathematical model of the...
