 Maps – Communicate spatial data/information through
“graphic symbols” – a language of location
 Cartography – the art and science of mapmaking –
increasingly an automated, computerized process
 Mapmaking process involves a number of interlinked steps:
 Data Gathering: Location Data, Attribute Data
 Data Compilation and Processing
 Cartographic Visualization and Design
 Map Drafting and Production
 The tasks involved depend on Types of Maps
Types of Maps
• General
Purpose Maps:
 General Reference Maps, Topographic Maps
• Special Purpose/ Thematic Maps:
Earthquakes in
Southern California
2000
 Dot Density Map – shows discrete locations/data
 Choropleth Maps – area-based nominal, ordinal
and continuous data
 Isopleth Map – point-based continuous data
isohyets (also isotherms, isobars, isobaths)
and contours
• Complex Special Purpose/ Thematic Maps:
 Composite Map – shows discrete + continuous data
(+ proportionate circles)
• Title (plus any explanatory text)
•
Legend or Key (See Appendix B)
•
Direction / Compass:
 True North, Magnetic North, Magnetic Declination,
Isogonic Map (with isogonic lines)
 Compass directions: Azimuth System (0˚ - 360˚)
and Bearing System, with four 90-degree
quadrants (NW, NE, SW, SE), e.g., North, 20˚
East (20˚ east of due north)
Map Basics – Continued
•
Map Coordinates:
a. Latitudes & Longitudes (Geographic Grid)
b. Rectangular/alpha-numeric coordinates
Simple Alpha-numeric
Location System
c. USPLS or Township & Range System
•
Map Scale: Map scale is the ratio of the distance between two
points on the Earth’s surface and the distance between corresponding
points on a map
 Verbal/Written/Stated Scale: 1 inch = 1 mile
 Bar/Graphic Scale: a graph depicting distances
 Representative Fraction:
One unit of measured distance on a map equal some units
of measured distance in the real world – 1: 63360
Also:
• Map Projection Used
•
Date, Author, Publisher, etc.

Large-Scale Maps show very small portions of the real
world, but with great detail
◦ Large-Scale maps have small denominators i.e.,
1:12,000 or 1:24,000
◦ Topographic maps are examples of large-scale maps

Small-Scale maps show very large portions of the real
world, but with minimal detail
◦ Small-scale maps have large denominators, i.e.,
1:100,000 or 1:1,000,000
◦ Wall maps are examples of small-scale maps
LARGE SCALE
SMALL SCALE
Modern Technology in
Data Gathering, Mapping and GIS
• Data Gathering:
Surveying – Field Survey using compass, chains,
plane table, and theodolite – to GPS
Originally developed for military use, GPS is being employed
in a variety of ways:
• GPS is widely used for ground, air, and sea navigation.
• And to produce accurate maps and study land
deformation caused by earthquakes and volcanic
eruptions. GPS is also showing up in more and more
commercial products.
The Global Positioning System or GPS consists of 3 parts:
1) Earth orbiting satellites
A set of 24 satellites constantly orbiting the Earth and
broadcasting their position and time…..Signals from 3
or 4 of them are used to pinpoint a location on earth,
using a procedure called trilateration.
Trilateration
2) Control and monitoring
stations across the Earth
3) GPS receivers owned by individuals and other entities
Aerial photography to satellite imaging
Multiple Platforms ↓
a)
Camera – Traditional and Digital
b)
Radar (SLAR, Doppler, Sonar)
c)
Near Infra-red (NIR) and Thermal Infra-red (TIR)
Scanners
d)
Multispectral Remote Sensing – Color
Composite Image

Typical Remote
Sensing Platforms
Polar vs. Geostationary Orbits
Remote Sensing
to Digital Mapping
All objects (natural or
synthetic) reflect and emit
electromagnetic radiation
over a range of wavelengths
characteristic of the object.
The Distinctive reflectance
and emitance properties are
the spectral signatures of the
objects.
Remote sensing operates in
the wavelength regions of the
electromagnetic spectrum
where these spectral
signatures occur, to identify,
map and analyze image
features
Landsat NIR image of San Francisco Bay
“Natural-color” Photograph
“False-color” Near infra-red
Satellite Image
Thermal Infrared (TIR) Image of a Storm System from GOES Satellite
Landscape Visualization: The Physical Environments of Cape Town
Satellite imagery and elevation data were combined and computer enhanced to produce the 3-D perspective
 Digital Mapmaking , involves:
 Converting locational/spatial data into digital
data → Cartesian Coordinates (x,y)
 Automated Contouring
 Digital Elevation Models: 3-D Representation
 Dynamic Maps
• Interface between Computer
Cartography and Data
Base Management
• A geographic information
system, GIS, is a
computer-based
technology that enters,
analyzes, manipulates,
and displays
geographic information
Watch this “GIS Day” video clip from ESRI for a more detail intro to GIS:
http://www.youtube.com/watch?v=IL1SKqtWB9Q&feature=related
• In a GIS framework both
spatial and non-spatial
databases are combined
into a “geodatabase”
• A GIS essentially creates
Map Layers of specific
thematic maps
• By layering the
information one on top of
the other, a geographer can
show, for example, the
relationship and degree of
connectivity between
various land uses and
transportation routes in a
region.
To summarize:
• A GIS involves Geocoding, Registration, Mapping,
Display, Analysis and other operations
• Also, Visualization Models
• A Great Planning Tool
Watch this for a City’s GIS:
http://www.youtube.com/watch?v=BG6XsFi4gfo&feature=related
For interactive GIS mapping, go to:
GIS City of Santa Clarita