Topic 3 Flashcards
two main map types
reference - shows where things are
thematic - has a theme, tells a story
what are the functions of symbols
- differentiate between things
- convey quanitity
- indicate location
- form meaning
- symbols can be geometric, mimetic, or literal
0d - 3d spatial dimensionality
0D - point
1D - line
2D - polygon (x,y independent)
2.5D - elevation (x,y independent, z is unique to a location)
3D - volume cube (x,y,z all independent)
describe discrete/continuous vs abrubt/smooth
discrete = abrubt
continuous - smooth
colour blend or hard edges
issues with choropleth maps
- does not show variation
- boundaries are arbitrary
- subject to jerry mandering (influencing districts)
- tenuous
- often doesnt show the complete picture of the data
what is a dasymetric map
use of ancillary data to redraw boundaries
choropleth + use another data source to shift boundaries
commonly used for population density
symbol scaling charactersitics
not straightforward
linear
area
volumetric
difference between geometric vs pictorial symbols
depends on the data you are trying to portray
geometric etter at showing quantity
describe dot maps
each dot represents a count of things
tend to locate them in an enumeration unit
suggests that the dots are where the people are
dot size and dot value are key factors
describe heat maps
in someway better than dot density
shows relative density of the dots
creates a continuous field
can result in random hotspots that dont exist
best when lots of dots are close together
whta is a cartogram
size of the enumeration unit is scaled proportionally with the represented value
maps that show environmental impact
trigger an emotional response
distorts area, size, sclae, shape etc to show significance of values
at one glance you can understand the data
the distortion IS the message
propoganda maps
what are flow maps
show direction and magnitude
show networks
shows distribution
key differences: isometric lines vs isoplethic
isometric - shows total values, shows derived values, attribute values occur at measurable points
isopleth/isoplethic - data occurs over an area, shows derived values of ratios
highly deceptive technique
examples of isometric uses/lines
above sea level - isohypses/contour lines
temperature - isotherm
barometric pressure - isobar
depth below sea level - isobath
rainfall - isohyet
legend characteristics
class is visually easier to interpret
DO NOT use the word “legend”
not naming the data set to look good is BAD
ex. population_density_2020 = Population Density (2020)
round classes to one decimal place
