Geog361 Final Flashcards
name 4 bivariate quantitative visual variables
size
lightness
spacing
saturation
name 4 bivariate qualitative visual variables
hue
shape
orientation
arrangement
describe distortion that occurs to latitude and longitude lines when they approach the poles
(in most projections)
the longitudes are often widened
the latitude lines are often compressed
name three examples of great circles
equator
prime meridian
international date line
on what kind of projection are latitude and longitude lines always parallel
there is NO projection where this occurs
lat and long lines are only parallel on globes
what does an azimuthal projection preserve
directions from a standard point
what is an orthographic
a projection made to look like a sphere
what is the goal when selecting standard lines
to place them in a way that minimizes distortion for the area of interest
what is a standard line
where the developable surface is touching the spheroid
where will a transverse cylinder’s standard line run
N to S on a meridian
what will a gnomonic projection preserve
the places you would fly over between 2 points
what happens when you run a simplify function on a line
points will be removed from the line
what happens when you run a smooth function on a line
points will be added to the line in order to reduce angularity
what does aggregation mean (outside the context of ArcGIS)
multiple points will be represented by an area at a smaller scale
what will a collapse function do
it will turn an area into a point
for example: the city footprint of Washington, DC may be turned into a star (point feature)
what does displacement do
it will move a feature or area farther from another feature or area in order to make the two distinct from one another
For example, one may push an island farther from a coastline at a smaller scale in order to accentuate the island.
what is exaggeration
increasing the size of a feature if it is important
the classic example is cape cod
example of enchance
rather than simply having road lines intersect river lines, add a bridge symbol to the road lines in order to enhance them
what is leading
separating the baseline between 2 words in a stacked label
what is the scale of a locator map compared to the main map
the locator map is at a smaller scale
what is the scale of an inset map compared to the main map and the locator map
the scale of the inset will be larger than both the locator and main map
name the four spatial dimension
point
area
line
volume
name the four variables of a model
discrete, continuous, abrupt, smooth
name the four levels of measurement
nominal
ordinal
interval
ratio
what is the model of a proportional symbol map
discrete and abrupt
what is the model of a dot density map
discrete and smooth
what is the model of a choropleth map
continuous and abrupt
what is the model of an isopleth map
continuous and smooth
what are the two parts of a bivariate combo
a quantitative and qualitative component
how do you create a porportional symbol for a linear bar
divide by the minimum value
how do you create a proportional symbol for areal symbols
take the square root and divide by minimum value
how do you create a proportional symbol for volume symbols
take the cubed root and divide by min
name the three basic color schemes
sequential
diverging
qualitative
how does a sequential color scheme work
values are simply high to low and often represented by the lightness of a color
an example would be amount of rainfall
what is the hallmark of a diverging color scheme
it has a meaningful central point
colors would go from dark to light to dark again
an example would be change in temperature
how do you set hue in an rgb scheme?
by setting proportion of RGB the higher proportion will be the color represented for example r=240 g=120 b=80 would display a more red color
how do you set the lightness in a rgb color scheme
the overall value of the rgb values
how do you set the saturation within an rgb scale
it is set using the lowest of the rgb values
equal interval
equal ranges in the data
max-min/ (#intervals)
quantile
equal observations per class #observations/#classes
standard deviation
the mean plus/minus a given number of standard deviations
natural breaks
done by eye or algorithms
what are the 2 main goals of a natural break classification
minimizing intraclass differences and maximizing interclass differences
when describing the type of model, do we refer to the phenomena or the representation of it
the phenomena itself
nominal data
named data with no natural order
ordinal data
non number data with a natural order for example (bad, better, best)
interval data
has a “meaningless” zero
temperature celsius
ratio data
will not include negative values
has a meaningful zero
height of children
what will an overall high rgb value do to lightness
it will be very light
the higher the rgb the lighter the value
how many font size points exist per inch
72
hue color separation is good for _____, while saturation is good for ______
classes
subclasses
gestalt principle
how humans perceive individual concepts as a whole
discrete phenomena
occurs at distinct locations with space between separating elements
continuous phenomena
occurs throughout geographic area of interest
example of abrupt phenomena
changes in electoral votes across states
example of smooth phenomena
precipitation throughout a region
dichromats
cannot see any difference between red and green
trichromats
have difficulty distinguishing between red and green
three steps to setting and rgb color value
set hue using proportion and highest rgb value
set lightness using a higher value of your optimal color
set saturation using the lowest of the rgb numbers
what is the name of the most common line simplification algorithm
douglas peucker
seperable
capable of being attended to independently of other dimensions
integral
cannot be processed without interference from other dimensions
configural
chracteristics of both inegral and seperable
new image or emerging properties may form
what should contours be used for
detailed metric elevation info
what should hypsometric tints be used for
relative elevation info
what should hill shading be used for
perception of overall landform shapes and backgrounds
does an isoline have to be a contour
no, it only means any line of equal value
isometric
true values at points
isoplethic
derived from area data to show conceptual form
interpolation
estimating data values in areas between known value
this can be done with isolines and grid data alike
name three developable surfaces
cylinder, cone, plane
what are the three projection classes
cylindrical
conic
planar (animuthal)
name four different projection aspects
equatorial
transverse
polar
oblique
name two different projection cases
tangent(simple)
secant
the 6 cases where you’ll want to generalize
congestion coalescence conflict complication inconsistency imperceptibility
4 steps of generalization
select
simplify
classify
symbolize
3 subclasses of generalization
content
geometry
symbolize
3 ways to generalize content
add
eliminate
reclassify
aggregate
replacement of many features with a representative feature of INCREASED dimensionality
collapse
replacement of a feature with a representative feature of LOWER dimensiuonality
merge
replacement of a feature with a representative feature of EQUAL dimensionality
AMALGAMATE
displace
adjustment of a feature to avoid coalescence with adjacent feature while maintaining topology
exagerrate
amplification of a portion of a feature to emphasize a characteristic aspect of it
smooth
removal of small variations in the geometry of a feature to improve its appearance
what were 2 recommendations put forth for USGS terrain representation
use a 5 point illumination model
add a 10% transparency to hillshade layer in order to allow curvature model to appear
what are the 5 illumination points recommended for the USGS terrain
NE N NW W SE
point label placement order (1-6)
NE SW NW SW N S
what is a breakline
when a label interferes with a line like a road. you can break the line with the font using a halo
contour lines commonly breaklines
name a few good color choices for the color blind
red blue orange blue brown blue yellow blue blue gray
induction
the problem that occurs when contrast of background makes you perceive colors differently in foreground
what will an overall higher magnitdue of colors equal
a lighter color
how can you change the saturation in an RGB scheme
lower the lowest of the color values
what are the three steps to RGB setup
set hue
set lightness
set saturation
do equal steps in RGB numbers mean equal visual steps
they do not, larger number steps are required for changes in darker colors (low numbers)
