Today

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Today

• Your writing assignment is posted!
• Portraying Earth
• Maps
• Map scale
• Map projections
• Isolines
• Global Positioning System (GPS)
• Remote Sensing
• Geographic Information Systems (GIS)

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Maps

• are 2-D, plan-view representations of reality
• show distance, direction, size, and shape
• let you customize your message
• change the complex to the simple
• facilitate discovery!

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Maps

• many uses
• ownership, political boundaries, weather,
  navigation, transportation, news/events,
  marketing, planning, construction, natural
  resource mgt., recreation, geology, landforms,
  landform processes, elevation, and more

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Maps

• a globe
• Advantages accurately represent shape, geometry,
  distance, size, and direction.
• Disadvantages ½ invisible at one time, very
  little detail, not very portable.

Globes are great for daydreaming and for quiet
contemplation (pg. 33)!
Vermeers The Geographer
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Maps

• Which map would you use to
• plan a hike in Yellowstone?
• find the location of a country?
• get to Kim, CO from UCCS?
• find a watershed?
• determine your local geology?
• find the population of El Paso County?

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Map Scale

• The scale of a map provides the relationship
  between
• distance on map
• the corresponding distance on ground
• Knowing map scale lets us
• measure distance
• determine area
• make comparisons of size

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Map Scale

• Large scale
• LARGE DETAIL, SMALL AREA (campus or building
  map)
• Small scale
• SMALL DETAIL, LARGE AREA (country or continent
  map)

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Map Scale
Less zoomed in
More zoomed in
Smaller scale
Larger scale
Smaller fraction
Larger fraction
image from http//rockyweb.cr.usgs.gov/outreach
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Map Scale

• Three common ways to express map scale
• representational fraction
• such as 124,000 (UNITLESS)
• verbal scale
• one cm to one kilometer (1100,000)
• one inch to one mile (163,360)
• graphic scale bar

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Map Scale

• Dont forget about the range of scales in
  scale!
• 11,000,000 example?
• 112,000 example?
• 11 example?
• 101 example?
• 1,0001 example?

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Quiz
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Map Projections

• Purpose to transfer info. from a spheroid to a
  flat surface

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Some distortion always results from the
projection process
Map Projections

• Distorted scale
• Distorted area
• Distorted distance
• Distorted shape
• Distorted size
• Distorted direction

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Map Projections

• Map projection families

cylindrical
planar
conical
Important The globes surface touches along
a STANDARD PARALLEL. What is unique about this
line?
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Map Projections
Important The globes surface touches along
a STANDARD PARALLEL. What is unique about this
line?
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Map Projections
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Map Projections
Where is the STANDARD PARALLEL?
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Cylindrical
- Equator normally the viewpoint - Typically used
to represent entire world - Latitude/longitude
lines perpendicular - Clipped map is rectangular
interrupted cylindrical
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Conic

• - Poles normally the viewpoint
• Only represent one hemisphere
• Good for mid-latitudes
• - Used for places w/ long East-West extent (US)
• - Clipped map is a SECTION of a circle

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Planar
- Only one hemisphere at a time - A Pole normally
the viewpoint - Unclipped map is circular
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Map Projections

• The dilemma should we distort area or shape
• - Using an equivalent projection, area stays same
  
• - Using a conformal projection, shape stays same

With conformal projections, SHAPE remains same.
With equivalent projections, AREA remains same.
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Isolines

• Isolines are lines that connect points of equal
  value.
• Isolines are always closed curves even though the
  map might only show part of it.
• Isolines NEVER cross.
• Isolines are usually parallel.

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Isolines

• A device to show spatial distribution of
  something on a map.
• Contour line equal ______ ?
• Isotherm equal ______ ?
• Isobar equal ______?
• Isohyet equal ______?
• Isogonic line equal ______?

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Isolines

• Contour lines

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Isolines

• Isotherms

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Isolines

• Isobars

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Isolines

• Isohyets

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Isolines

• Isogonic lines

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Global Positioning System
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GPS in Google Earth
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• THE WHITE HOUSE Office of the Press Secretary
  For Immediate Release May 1, 2000 
• STATEMENT BY THE PRESIDENT REGARDING THE UNITED
  STATES' DECISION TO STOP DEGRADING GLOBAL
  POSITIONING SYSTEM ACCURACY

Bill Today, I am pleased to announce that the
United States will stop the intentional
degradation of the Global Positioning System
(GPS) signals available to the public beginning
at midnight tonight. We call this degradation
feature Selective Availability (SA). This will
mean that civilian users of GPS will be able to
pinpoint locations up to ten times more
accurately than they do now.
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GPS accuracy before and after selective
availability removal
MAY 1, 2000 MAY 3, 2000
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Remote Sensing
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Remote Sensing
Proportion of energy reflected, absorbed, or
transmitted from the earth surface vary for
different earth features. These differences
allow us to distinguish even the most subtle
changes/characteristics from an image.
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Remote Sensing
Definition measuring or acquiring information
from a surface using a device that is not in
direct contact with the surface.
PASSIVE remote sensing Aerial photos (balloons,
planes, satellites, shuttles) Orthophotos
(georeferenced images) Color and color infrared
(blue filtered out, vegetation is seen as
red) Thermal infrared (detect heat, water vs.
land, GOES Weather Satellites) Microwave sensing
(longer wavelengths, see moisture
well) Multispecral (Landsat, Earth Observing
System, 36 spectra at a time, 1-2 days)
ACTIVE remote sensing Radar (Radio Detection And
Ranging) Sonar (Sound Navigation Ranging) Lidar
(Light Detection And Ranging)
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Remote Sensing
near infrared (0.8 1.4 microns)
green light (0.4 0.7 microns)
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Geographic Information System (GIS)
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GIS
A GIS stores information about the world as a
collection of thematic layers that are linked
together by geography.
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GIS
- people
- spatial data

• software

• hardware

- analysis
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GIS

• - What in the world is GIS, anyway?
• Definition A tool that allows for the
  processing of SPATIAL data into information,
  generally information tied explicitly to, and
  used to make decisions about, some portion of the
  earth (DeMers, 2000)

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WHAT IS NOT A GIS?

• WHY or WHY NOT?
• A map
• MapQuest
• ArcView or ArcGIS
• Rating wildfire potential in Arizona
• Global Positioning System (GPS)