GEOG363 EXAM 1 Flashcards
data integration
bringing different sets together to be used
what does visualization do?
it reveals hidden relationships between things to communicate ideas
geoprocessing
computing data onto a map
hipsometric
different colors describing different elevations
Eucledian space is also known as
cartesian coordinates
tuple
ordered set of numbers EG (x,y)
topology
ignores metric details and idenitfies relational structures or how things relate in space
discrete
has defiend edges
continuoes
does not have defined edges
what type of map is discrete and has object view
vector
what type of map is continous and has field view
raster
tesselations
pixels
interval data
continuous data that can be negative
ratio
has a natural zero EG height
3 componenets of geospatial data
spatial
thematic
temporal
what 2 things define vector data
magnitudew and direction
3 components of 3 tubule
lat long and height
node
has start, endpoint, intersection
is a special case of a vertx
vertex
simply a point on a line
what do rows represent
features
what do columns represent
attributes of features
what do spherical coordinates measure
angles with lambda and phi
name 2 great circles on earth
the equator and the prime meridian+int date line
name 2 examples of small circles on earth
the tropics of capricorn and cancer
what is the difference in the way the prime meridian and the equator are determined
the equator has right angles to the earth’s axis and the prime meridian is arbitrary
how is a geoid determined
it is the physical model that is based on surface gravitational pull
datum
a set of reference points
datum shift
differences in coordinates between datum
planimetric
accurate with cartesian coordniates
azimute
defines the direction you are facing in degrees
aspect
position from which projection is centered and viewed
transversal rotation
rotating the globe so that north and south aren’t up and down
what does conformality preserve
azimuths or direction and angles
preserves area in projections
equivalence
tissot indicotric
circles that represent distortion in projections
if circles are circular what is being preserved
conformity
if circles remain the same size that preserve…
equivalence
what 2 things do cartesian systems have
a fixed origin and coordinates
generalization
simplifying detailed lines when decreasing scale
what is the most common shape of a tessellation
square
2 terms that refer to pixels of raster images
cells or more rarely grid elements
whta is the smallest distinguishgable unit in a raster
a cell
nyquist shannnon smapling theory and which sub-field of GIS does it relate to
resolution should be atleast 1/2 as fine as the smallest image we wish to detect
remote sensing
Any cell rule
always continuous but wider line
Near center rule
Thin line but may be discontinuous
what does post processing do
smooth lines when converting from raster to vector
bit-depth
how many bits
TIN
triangulated irrwegular network
Vector models produce smaller data sets
● Topological relations are better handled using vectors
● Analysis is simpler on raster data in many cases
● Overlays are simple in the raster model
● TINs provide flexible facet sizes (efficiency)
k
what do horizontal datums describe
points against which latitude and longitude can be measured
what do vertical datums describes
points against which heigh or depth can be measured
what is the most popular datum system and what two giants use it?
WGS 84
google earth and gps
why does datum shift occur
different datum points use different best fit ellipsoids of earth to best describe specific areas
rhumb or loxodrome
a course of constant bearing used by mariners
2 important properties of the Lambert conformal conic
it is true along 2 standard parallels and works for a country’s east to west expanse
name 3 properties of the UTM
- good for north to south expanse
- are 6 degrees wide
- origin is 500,000 meters west of central meridian (EQUATOR IS ZERO IN NORTHERN HEMISPHERE AND ANTARCTICE IS ZERO IN SOUTHERN
gnomonic map projection
turns great circles into straight lines tangentally.
