Spatial Reference System Flashcards
the shape of the earth given by the gravitational equipotential surface
geoid
according to gravitational theory, if the Earth were homogeneous in composition, its shape would be an _____ of rotation
ellipsoid
equator radius is shorter than those at the poles
ELLIPSOID
according to gravitational theory, if the Earth were homogeneous in composition, its shape would be an ____ of rotation
ellipsoid
The rotation of the Earth, which generates centrifugal force, causes its _____ shape
ellipsoidal
`the flattening at the poles amounts to only ___
1/298
also means that the radius at right angles to the axis of rotation is slightly greater than that along, the axis, thereby creating the major and minor axes
ellipsoidal shape
- from the geometric interpretation of Descartes, the cartesian coordinate system
- linear distances (meters, feet)
PLANE COORDINATES
- angular measurement is used based on the sexagesimal scale (degree, minutes, second)
SPHERICAL/GEOGRAPHIC COORDINATE SYSTEM
how we travel from a certain reference
how far from prime meridian
east to west
longitude
All spatial data is a _____
coordinate reference
2 main types of coordinate reference
Geographic - use a spherical coordinate
Projected (plane geometry)
lambda — ____
phi — ______
longitude, latitude
converting lambda and phi to x and y
map projection
characteristic ng ellipsoid and how that ellipsoid would fit in a local area we’re mapping
DATUM
Combining the info of ellipsoid
characterize ellipsoid into showing that it is close to the local characteristic
DATUM
The combination of a reference surface (the ellipsoid) and a point in which it is linked to the geoid
DATUM
3D to 2D
parameters of projection
measurement units (feet or meters)
PROJECTION
PROPERTIES OF GRATICULES ON SPHERE
Parallels are true east-west lines.
Parallels are equally spaced between equator and the poles.
Parallels are always,,,, PARALLEL to one another
Meridians are spaced farthest along the equator and converges at the poles
Parallels and meridians cross at right angles.
types of distortion
shape
area
distance
direction
what are the changes when we project maps
hindi na right angle
iba ung radius
not just the graticules will change pati ung map itself
look at distortion ellipses
all spatial data is in a coordinate reference (t or f)
t
Lat/long good for locating ____ on surface of a globe.
positions