GISP EXAM STUDY GUIDE
Georeferencing - Answers - 101- associating a map or image with spatial location
control points - Answers - 101- points come in pairs that match the spatial location with
a point on an unreferenced image or map
Spatial Reference Systems (SRS) - Answers - 101- coordinate based local, regional,
or global system used to location geographical entities (aka Coordinate Reference
System (CRS))
Coordinate Reference System (CRS) - Answers - 101- coordinate based local,
regional, or global system used to location geographical entities (aka Spatial Reference
Systems (SRS))
International Terrestrial Reference System (ITRS) - Answers - 101- 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)
Map projection - Answers - 101- transforming coordinated from a curved surface
(Earth) to a flat map
Horizontal datum - Answers - 101- 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)
Vertical Datum - Answers - 101- reference point for measuring elevations
NAVD88 - Answers - 101- Gravity based geodetic datum in North America
WGS 84 (World Geodetic System) - Answers - 101- reference coordinate system used
by the Global Positioning System (GPS)
SRID integer - Answers - 101- Spatial reference system id numbers, including EPSG
codes defined by the International Association of Oil and Gas Producers
types of distortion - Answers - 101- Distance, Direction, Shape, Area (sometimes
bearing and scale)
Mercator Projection- distortions - Answers - 101- preserves shape and direction, area
gets distorted
Mercator Projection - Answers - 101- projecting the Earth onto a cylinder tangent to a
meridian
,Azimuthal Projection- distortions - Answers - 101- distance from center is true, other
properties distort with distance
Azimuthal Projection - Answers - 101- planar or tangent (meaning they are formed
when a flat piece of paper is placed on top of the globe and a light source projects the
surrounding areas on to a map.) Either the North Pole or the South pole is orientated at
the center of the map, giving the viewer an impression of looking up or down at Earth.
Cylindrical Projection- distortions - Answers - 101- preserve area and shape, distance
gets distorted, especially on upper and lower regions of the map
Cylindrical Projection - Answers - 101- 2 types Tangent (1 intersect) and Secant (2
intersects)
Straight meridians and parallels
meridians are equally spaced while parallels are not
Conical Projection- distortions - Answers - 101- preserves direction and area in limited
areas, distorts distance and scale except along standard parallels
Conic Projections - Answers - 101- mapped to equally spaced lines by projecting a
spherical surface onto a cone
Choosing a Projection- Low LATITUDE, (near Equator) - Answers - 101- use conical
projection
Choosing a Projection- High LATITUDE, Polar Regions - Answers - 101- use
azimuthal planar projections
Choosing a Projection- EXTENT, broad East-West (e.g. USA) - Answers - 101- use
conical projection
Choosing a Projection- EXTENT, broad North-South (e.g. Africa) - Answers - 101- use
transverse-case cylindrical projection
Choosing a Projection- THEMATIC, analysis that compares different values in different
locations - Answers - 101- use an equal-area projection
Discrete features - Answers - 102- feature has a definable boundary (think, "vector")
continuous phenomena - Answers - 102- each location is a measure of something,
often temperature or elevation (think "raster", but not always)
Geoid - Answers - 103- the shape that the surface of the oceans would take under the
influence of Earth's gravitation and rotation alone (absent of the influence of wind or
tide)
, Mean Sea Level (MSL) - Answers - 103- is determined by referencing the geoid model
which registers ocean's water level at coastal places using tide gauges
Reference Ellipsoid - Answers - 103- is a mathematically defined surface that
approximates the geoid (a truer model of shape that geoid)
oblate ellipsoid - Answers - 103- fits the geiod model to a first order approximation
formed when an ellipse is rotated about its minor axis (The shape of the Earth, slightly
bulging at the Equator.)
sphere - Answers - 103- can be seen from dimensions of the Earth ellipsoid
the semi-major axis (a) and semi-minor axis (b) differ by little more than 21 kilometers
first (direct) geodetic problem - Answers - 103- Given a point (coordinates) and
direction (azimuth) and distance from that point to a second point, determine the
coordinates of a second point
Be prepared for Word Problems like this one
Second (inverse) geodetic problem - Answers - 103- given two points, determine the
azimuth and length of the line that connects them (line may be straight, arc, or
geodesic)
Be prepared for Word Problems like this one
Geomatics - Answers - 104- branch of science (and technology) of collection, analysis,
interpretation of geographic information
(includes surveying, mapping, remote sensing, GIS, GPS)
GPS (global positioning system) - Answers - 104- A system that determines the
precise position of something on Earth through a series of satellites, tracking stations,
and receivers.
Spatial Modeling - Answers - 201- A methodology or set of analytical procedures used
to derive information about spatial relationships between geographic phenomena.
Types of spatial models - Answers - 201-
Vector
Raster
Pixel
Geodatabase
Grid
TIN
Topological
Hierarchical
Network
Object Oriented
Georeferencing - Answers - 101- associating a map or image with spatial location
control points - Answers - 101- points come in pairs that match the spatial location with
a point on an unreferenced image or map
Spatial Reference Systems (SRS) - Answers - 101- coordinate based local, regional,
or global system used to location geographical entities (aka Coordinate Reference
System (CRS))
Coordinate Reference System (CRS) - Answers - 101- coordinate based local,
regional, or global system used to location geographical entities (aka Spatial Reference
Systems (SRS))
International Terrestrial Reference System (ITRS) - Answers - 101- 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)
Map projection - Answers - 101- transforming coordinated from a curved surface
(Earth) to a flat map
Horizontal datum - Answers - 101- 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)
Vertical Datum - Answers - 101- reference point for measuring elevations
NAVD88 - Answers - 101- Gravity based geodetic datum in North America
WGS 84 (World Geodetic System) - Answers - 101- reference coordinate system used
by the Global Positioning System (GPS)
SRID integer - Answers - 101- Spatial reference system id numbers, including EPSG
codes defined by the International Association of Oil and Gas Producers
types of distortion - Answers - 101- Distance, Direction, Shape, Area (sometimes
bearing and scale)
Mercator Projection- distortions - Answers - 101- preserves shape and direction, area
gets distorted
Mercator Projection - Answers - 101- projecting the Earth onto a cylinder tangent to a
meridian
,Azimuthal Projection- distortions - Answers - 101- distance from center is true, other
properties distort with distance
Azimuthal Projection - Answers - 101- planar or tangent (meaning they are formed
when a flat piece of paper is placed on top of the globe and a light source projects the
surrounding areas on to a map.) Either the North Pole or the South pole is orientated at
the center of the map, giving the viewer an impression of looking up or down at Earth.
Cylindrical Projection- distortions - Answers - 101- preserve area and shape, distance
gets distorted, especially on upper and lower regions of the map
Cylindrical Projection - Answers - 101- 2 types Tangent (1 intersect) and Secant (2
intersects)
Straight meridians and parallels
meridians are equally spaced while parallels are not
Conical Projection- distortions - Answers - 101- preserves direction and area in limited
areas, distorts distance and scale except along standard parallels
Conic Projections - Answers - 101- mapped to equally spaced lines by projecting a
spherical surface onto a cone
Choosing a Projection- Low LATITUDE, (near Equator) - Answers - 101- use conical
projection
Choosing a Projection- High LATITUDE, Polar Regions - Answers - 101- use
azimuthal planar projections
Choosing a Projection- EXTENT, broad East-West (e.g. USA) - Answers - 101- use
conical projection
Choosing a Projection- EXTENT, broad North-South (e.g. Africa) - Answers - 101- use
transverse-case cylindrical projection
Choosing a Projection- THEMATIC, analysis that compares different values in different
locations - Answers - 101- use an equal-area projection
Discrete features - Answers - 102- feature has a definable boundary (think, "vector")
continuous phenomena - Answers - 102- each location is a measure of something,
often temperature or elevation (think "raster", but not always)
Geoid - Answers - 103- the shape that the surface of the oceans would take under the
influence of Earth's gravitation and rotation alone (absent of the influence of wind or
tide)
, Mean Sea Level (MSL) - Answers - 103- is determined by referencing the geoid model
which registers ocean's water level at coastal places using tide gauges
Reference Ellipsoid - Answers - 103- is a mathematically defined surface that
approximates the geoid (a truer model of shape that geoid)
oblate ellipsoid - Answers - 103- fits the geiod model to a first order approximation
formed when an ellipse is rotated about its minor axis (The shape of the Earth, slightly
bulging at the Equator.)
sphere - Answers - 103- can be seen from dimensions of the Earth ellipsoid
the semi-major axis (a) and semi-minor axis (b) differ by little more than 21 kilometers
first (direct) geodetic problem - Answers - 103- Given a point (coordinates) and
direction (azimuth) and distance from that point to a second point, determine the
coordinates of a second point
Be prepared for Word Problems like this one
Second (inverse) geodetic problem - Answers - 103- given two points, determine the
azimuth and length of the line that connects them (line may be straight, arc, or
geodesic)
Be prepared for Word Problems like this one
Geomatics - Answers - 104- branch of science (and technology) of collection, analysis,
interpretation of geographic information
(includes surveying, mapping, remote sensing, GIS, GPS)
GPS (global positioning system) - Answers - 104- A system that determines the
precise position of something on Earth through a series of satellites, tracking stations,
and receivers.
Spatial Modeling - Answers - 201- A methodology or set of analytical procedures used
to derive information about spatial relationships between geographic phenomena.
Types of spatial models - Answers - 201-
Vector
Raster
Pixel
Geodatabase
Grid
TIN
Topological
Hierarchical
Network
Object Oriented
