Q1
Georeferencing
Answer: associating a map (such as a pdf without spatial information) or image (such
as an aerial image without spatial information) with spatial locations
Q2
Control points
Answer: consisting of multiple points, points come in pairs that match the spatial
location with a point on an unreferenced image or map
Q3
Spatial reference system (SRS) or coordinate reference system (CRS)
Answer: a coordinate-based local, regional, or global system used to locate
geographical entities
Q4
International Terrestrial Reference System (ITRS)
Answer: It is a three-dimensional coordinate system with a well-defined origin (the
center of mass of the Earth) and three orthogonal coordinate axes (X,Y,Z)
Q5
Map projection
Answer: transforming coordinates from a curved earth to a flat map
Q6
Horizontal datum
Answer: model of the earth as a spheroid (2 components, reference ellipsoid and a set
of survey points both the shape of the spheroid and its position relative to the earth)
, Q7
Vertical datum
Answer: reference point for elevations of surfaces and features on the Earth - could be
based on tidal, seas levels, gravimetric, based on a geoid
Q8
NAVD88
Answer: gravity based geodetic datum in North America
Q9
Geodetic datum
Answer: set of control points whose geometric relationships are known, either through
measurement or calculation
Q10
WGS 84
Answer: World Geodetic System - reference coordinate system used by the Global
Positioning System (GPS)
Q11
SRID integer
Answer: spatial reference system id numbers, including EPSG codes defined by the
International Association of Oil and Gas Producers
Q12
4 distortions
Answer: Distance - Direction - Shape - Area
Q13
Mercator Projection
Answer: Preserves shape and direction, area gets distorted projecting earth onto a
cylinder tangent to a meridian