Lecture 5

TYPES OF MAP

1. Planimetric maps
- Show only where things are.
- only outlines or locations, very limited information.
--- base map (to plot other data on)
--- cadastral map (to show legal lot boundaries, ownership of land)

2. Topographic maps
- Detailed description of the landscape, usually including some representation of elevations
- as much other information as scale and user needs allow.
--- topographic map series (e.g. NTS in Canada). Multiple sheets, standard scales, frequent revisions.
--- nautical (bathymetric) charts - same as above for the sea or large lakes, with water depth, navigation aids and hazards.

3. Thematic maps
Distribution of one specific type of phenomenon (the theme of the map) or a relationship between phenomena.

- examples: Population, land use, Geology, Land Prices, Climate, Resources

THEMATIC MAPS

1. Subject
- Can cover any subject for which data are available.

2. Maps used alone as reference tools
- geologic map, zoning map: used for planning or research
--- must include a full explanation of symbols and other explanatory material.

3. Maps used to illustrate text
- figures in a thesis, book, journal, newspaper
--- must include a partial explanation of symbols etc., but may also be partly explained in text.
--- may use a caption near the map in place of a title on the map.

4. Representation
- Many different methods.
- Thematic maps are classified by method of representation
- Data plotted on base map (simplified outline which helps the user locate the information being depicted)

TYPES OF DATA

1. Dimensions
- point data: refers to a single point
--- may be a spot where something was measured or a city on a world map. Size of point depends on map scale.
- linear data: refers to an ideal line (width ignored)
--- real (river, road)
--- abstract (boundary, equator, route)
- area data: refers to a political or administrative unit, geological or climatic region etc., with a finite area. --- Data often averaged over that area.

2. Discrete and Continuous Data
- discrete data refer to specific points
--- do not exist between those points
--- e.g. city population, mines, shipwrecks
- continuous data could be measured anywhere
--- in fact measured (sampled) only at specific points
--- e.g. rainfall, elevation, air pressure
--- or averaged over an area
--- e.g. population density, mean income

REPRESENTATION OF DATA

Area Classification and Discrete Symbols
- The two basic types of thematic map representation
- there is some overlap between the types

1. Area Classification Maps
- divide map into regions having different characteristics.
--- geologic regions
--- vegetation regions
--- population densities
--- elevation zones

- regions distinguished by labels, patterns, colours.

2. Discrete Symbol Maps
- distinguish points or regions with individual graphic symbols
--- geometric or pictorial symbols
--- may vary in size or form to indicate value