Isarithmic mapping Flashcards
what is a isarithmic map
portrays continuous surfaces using isolines
what is an Isoline
quantitative line features that represent a constant value
how are isolines created
with located reference control points
what do isolines usually depict
- elevation
- slope
- aspect
- variability or ruggedness
How are isolines interpreted
based on magnitude, spacing and frequency.
what are the two types of isarithmic maps
isometric and isoplethic
what is an isometric map
represent continuous data, most common
what is a isoplethic map
areal discrete data, represented at point locations.
aspatial data requirements for isometric
- Raw or derived values for isometric
aspatial data requirements for isplethic
- derived values used, never raw values.
when is it used
Only method for mapping continuously distributed data as a surface.
what are Datum and interval
Datum is the starting point for measurement
Interval is the change in value between consecutive isolines
what can datum be?
real or arbitrary zero value
a minimum value of the dataset
why are intervals used?
affects number of isolines, and affects appearance
how do you label isolines
- interrupting the isolines
-at the end of the line - not every line needs to be labeled
what map projection should be used
conformal
