chapter 7 – mappingannarborearthscience.weebly.com/.../mapping.pdf · powerful computer...
TRANSCRIPT
Mapping
Chapter TopicsMaking Accurate Map ProjectionsLatitudeLongitudeGreat CirclesMap ScaleContoursSlopeRemote SensingGIS
Making Accurate Map Projections
Distortion
Round surface on a flat paper
Mercator,gnomic,conic most common
LatitudeThere is an imaginary line of latitude halfway between the North Pole and the South Pole called the equator. There are other lines of latitude that are north and south of the equator. They are parallel lines which are equal in distance apart at all points. They run east-west around the globe. Parallels measure distance north or south of the equator in degrees.
LongitudeThere are also imaginary lines of longitude that help us measure distance east and west. Each line of longitude, or meridian, runs from the North Pole to the South Pole. Mapmakers needed a place to begin, so they created the Prime Meridian as this starting point. Meridians are the farthest apart at the equator, and they are closer together at the poles.
Latitude and Longitude
Measured in degrees.
Latitude 0-90 North or South
Longitude 0-180 East and West
Broken down further into minutes and seconds
Example: 12º 32’ 8” N
Great CirclesShortest distance on a round surface in an arc.
Map ScaleGraphic
Verbal
Representative fraction
Example 1:5000
One inch on the map is equal to 5000 inches in the real world.
Contour LinesConnects areas of similar elevation.
Contour interval
Index Contours
Make 3D models from 2D lines.
SlopeRise in elevation over the run the distance.
Rise / Run
Geographic Information SystemsGIS
Introduction Computer tool: geographic map + tabular data
Integrate: Database, Mapping, Analysis
Create maps which convey information
Countries w/ Population>100 million
What is GISPowerful computer mapping/analysis system
Easily make/update maps
Analyze locations & Present info as maps to:
Integrate maps & info from variety of sources
Make decisions about resources, planning, site selection, demographics
How GIS worksLinks map features to tables of attributes
Access the attributes for any map feature
Locate any feature from its attributes
Manage sets of features & attributes as themes
Basic Features
Create maps
Make queries, what if scenarios
Summarize and analyze data
Integrate information
Remote Sensing
HistoryCivil War: balloon photography
WWI & II: military air reconnaissance
1940: aerial photos for peacetime use (surveying, mapping , soil survey)
1960: digital computer, improved sensors, quantitative pattern recognition software
Improved computers, increased spectral bands & sensor capability, satellite speed, wide range of altitudes/resolutions lead to large quantity of info
Defined
Use of airborne sensors (mainly satellite)
which measure electromagnetic radiation of objects
to monitor, analyze & extract info about earth features and the environment
ImportanceLarge changes are happening
Observe location & extent of human activity and land cover
Monitor rates of change
Make global evaluations
Link to GIS
Why use RS (vs ground survey)
Large regional view
Complete area (spatial) coverage
Temporal change: snapshots over time
Cost effective
OtherCan provide 3d view
Detect characteristics not visible to eye
Uses: land, air, water, space Vegetation: forests, crops , range lands
Soils/Geology: terrain, minerals, faults
Water resources, Marine environment
Environment: ozone, pollution, habitat
Natural disaster: flood, fire, volcano
People: urbanization, population growth
Regional planning, Weather, Global Climate
Cartography mapping, Surveying
Military
Remote Sensing Examples
Cape Canaveral Landsat 7
Oakland Landsat 7
Change: Aral Sea
Change: same area, #3 is change
Change: urban growth D.C.Dark=no change, bright=development since 1973
Landsat TM
Sediment Model
DEM: digital elevation model
3D: stereo pairs
Flood extent impossible by ground survey, green veg
Landsat TM
Floods: Missouri river
Junction w/ Grand riverJunction w/ Grand river
2=B 4=G 5=R Bare soil, plowed land are red, vegetation (hi near infrared-4) is green, water is dark blue.
19931992
Landsat TM
El Nino sea temptop: normalmiddle: el ninobottom: change
Environment: Ozone
Global: snow (microwave)
Global: Vegetation avhrr, coarse, desertification
Deforest: Amazon change, near road
Forest change: U.S.
2=B 4=G 5=R wide range, conifers are dark green, soil or cultivated land is reddish, snow is light blue. Land use policy led to less clearcuts.
19951984
Landsat tm
Olympic natl forest
RS+GIS, Quantify Habitat loss
Hazards: gulf war oil fire Landsat TM
Crater Lower Amazon in Bolivia
1988 scene, not visited until 1998 cause so inaccessible
1988 scene, not visited until 1998 cause so inaccessible
Landsat 1988, inaccessible so no visit until 1999
Volcanoes: Mt St Helens
False vs True: Mt St Helens
1=B 2=G 3=R true2=B 4=G 5=R wide range
Landsat tm May 1992
Scale problem
whaleswhales
QuickTime™ and aCinepak decompressor
are needed to see this picture.