From thematic cartography: Attribute and location
two basic components of maps
Maps, as normally presented,
are actually classified in terms of treatment of attributes:
Example: Exxon Valdez oil spill by day...
Sounds obvious. useful starting point to remember [BASIS OF THIS COURSE!]
A reference system incorporates a package of decisions about measurement of some property; it provides a means to compare things (at the simplest level). [Resources]
BASIC POINT: time is measured as a "distance", elapsed from some established starting point. A reference system implies a unit of measure and an origin along a "time line". These conventions become so accepted, they are taken for granted...
A spatial reference system includes:
These decisions are often packaged up into a conventional coordinate system (spatial reference system) such as UTM or State Plane (in the USA)
a special case, with extra concerns:
In physics (and in pulp sci-fi), it is common to refer to space and time together, since the theory of relativity makes them impossible to separate. At geographic rates of speed, these effects are hard to detect, but still it makes sense to think of a composite, using Hägerstrand's space-time diagrams.
Much more complex than seven "basic" physical measurements and derived composites.
Examples abound: in the legend of any map. [limited only by your
imagination!]
Population, population density, Year of maximum population, Dollars of household income per month, Vegetation type, Zoning, soil bulk density, and on and on ...
Fish and Wildlife Service "Cowardin" manual for wetland classification (and its official hierarchy)
This is a preview of the next lecture (about levels of measurement...)
Level of measurement: Information required Nominal definitions of categories Graded membership definition of categories plus degree of membership or distance from prototype Ordinal definitions of categories plus ordering Interval unit of measure plus zero point Extensive ratio unit of measure (additive rule applies) Cyclic ratio unit of measure plus length of cycle Derived ratio units of measure (ratio of units; weighting rule) Counts definition of objects counted Absolute type (probability, proportion, etc.)
The rows in grey are additions to the classical levels of measurement as taught in other geography courses....