Tc1-3

Front 1

Interval Linear Symbols

Back 1

Time (isochrones)
Elevation (isobase or contours)
Temperature (isotherms)

Front 2

Ratio Linear Symbols

Back 2

Flow Maps
Direction
Amount

Front 3

LINEAR DATA

Back 3

INFORMATION ON LOCATION
PLUS INFORMATION ON
Attribute (the topic or theme)
Amount (size or rank or pathway)
Direction (sometimes generalized)

Front 4

Quantitative Flow Maps

Back 4

QUANTITATIVE lines usually scaled so that widths are proportional to the amounts they represent (cost, tons, people, etc)
Traffic Flow Maps
Population Flow Maps
Commodity Flow Maps
Desire Line Maps

Front 5

Flow Map Pro/Con

Back 5

POSITIVE
VERY EFFECTIVE FOR LINEAR DATA INVOLVING MOVEMENT OF SOMETHING
NEGATIVE
DIFFICULT TO CONSTRUCT
DIFFICULT FOR READERS TO ESTIMATE SIZE

Front 6

Flow Map Guidelines

Back 6

Flow lines are most important
Smaller lines on top of larger lines
Arrows necessary if direction is critical
Land and Water contrast is essential
Projection, center and aspect important
Keep information simple
Legend should be clear and unambiguous

Front 7

Dot Density Alternative Name

Back 7

Also called Aerial-Frequency Mapping

Front 8

Data Types

Back 8

Discrete geographic phenomena
Raw data (count data)
Qualitative or Quantitative Map

Front 9

One dot equals one item

Back 9

ONE DOT EQUALS ONE ITEM
Qualitative
Nominal Scale
Location accurate

Front 10

One dot equals many items

Back 10

ONE DOT EQUALS MORE THAN ONE
Quantitative
Ordinal scale (apparent densities)
Location generalized (spatial proxy)

Front 11

Dot Density Pro/Con

Back 11

Positive
good visual impression
easy to construct
Information inside of enumeration units
Negative
limited information
not intended for determining exact quantities

Front 12

Dot Value Guidelines

Back 12

Should be a rounded number, no fractions
Minimum 2-3 dots per unit
Should be tested with different sized dots using the unit with the highest density – dots should just start to merge.

Front 13

Enumeration Units

Back 13

Enumeration Units
Smaller the unit the greater the accuracy

Dot Density map

Front 14

Dot Location Guidelines

Back 14

(1) Transition: dots should transition from high density to low density across units
(2) Boundary Effect: dots should be located near and on boundaries
(3) Ancillary variables
a. Limiting variables (ponds, parks etc)
b. Related variables (roads, soils etc)

Front 15

Dot distribution methods

Back 15

Uniform
Geographically Weighted
Geographically Based