Geology Exam 2
How does the property of Color Hue enhance the readability of a nominal data types?
Give impression of difference, but no impression of magnitude
What is a continuous surface? List some examples and describe some characteristics.
Gradual changes across the surface Magnitudes can be measured at all locations on the surface Data collected through sampling techniques All other variables are interpolated from the sample data Isoline Maps Layer-tinted Isotherms Dot Density Repeated point symbol across surface - Dots, squares, triangles, etc Each symbol represents more than one feature (i.e., Point symbol maps represent one feature's location) Multivariate Graduated Colors
Planar Projections
slide 13
There are 2 Origins for each zone (Easting and Northing)
Coordinate Pairs Easting - starts west of the central meridian Northing - starts at equator
How does the property of color Value and Saturation enhance the readability of quantitative map types?
area features: Can be symbolized using: Size Texture Color Value - lightness Color Saturation
Stereographic (light source) slide 8
from the top all the way down 1. Antipodal light source, point of light projection is opposite the point of tangency 2. Stereographic Conformal Projection 3. Scale increases away from center point 4. Lines of Latitude become increasingly farther apart moving away from the point of tangency 5. Meridians converge at the poles 6. Great circles are straight lines from the center point 7. Most common: Polar Aspect Secant Case Above 80°N or 80°S
Gnomonic (light source) slide 9
from the top to the middle 1. Light source from Earth's center 2. Scale increases away from center point 3. Meridians are always straight lines 4. All great circles are shown as straight lines 5. Extreme shape and area distortion away from center point of tangency 6. Cannot project a full hemisphere
What are the dimensions of a Township and a Section?
TOWNSHIP measures the distance NORTH or SOUTH from the BASE LINE which is a designated parallel.
How is this system different from the UTM and SPC grid systems? look on: http://education.usgs.gov/lessons/coordinatesystems.pdf
UTM: On the Transverse Mercator projection. Latitude-longitude is valuable because one can use the globe to introduce the concept and because it is the first coordinate system that students learn. However, in latitude-longitude, there may be 7 seconds between one end of a large building the other, or (7/3600) = .0019 degrees. Seconds and fractions of degrees can be difficult distances to visualize and work with. In contrast, the UTM unit is the meter, a length that students already understand. SPC: This system is actually a series of separate systems, each covering a state, or a part of a state, and is only used in the United States. Its high accuracy, achieved through the use of relatively small zones. The system is designed to have a maximum linear error of 1 in 10,000 and is four times as accurate as the UTM system.
Orthographic (light source) Week 6, slide 6
infinity (all around) 1. Infinite light source 2. Meridians converge at the poles 3. Distances are preserved along parallels 4. Best for showing true perspective of Earth as it looks from space
Know how to record a parcel of land with PLSS nomenclature. slides 7-10
look at: http://dnr.wi.gov/topic/forestmanagement/documents/plsstutorial.pdf
Understand the formatting of the USNG coordinate pairs * Grid Zone Designation * 100,000 meter square grid codes (2 letter codes) * Precision within 1 meter, 10 meters, 100 meters, 1,000 meters areas
slide 3
Dymaxion (Buckminster Fuller's map) slide 23
picture
points of tangency
polar, equatorial, oblique
Which light source creates an equal area cylindrical map? Equal area?
red?
What are the 2 projection systems used for this grid coordinate system? slide 7
secant case
What is an initial starting point? How many are there? o Principle Meridian and base lines? slide 2
Metes and Bounds Running prose style around the property Begin at starting point, end at the starting point Used physical features to describe locations No Surveying skills required 1. Beginning with the Large White Oak 13 poles above the Sinking Spring, or Rock Spring, Running thence North 9 1/2 degrees East, 310 poles to a stake in John Taylor's field, thence South 89 1/2 degrees East, 310 poles to two Blackjacks, then North 89 1/2 degrees East, 155 poles to the beginning. (Abraham Lincoln's birth place, 1809)
How many zones are there? Where does Zone 1 start?
1. 60 zones Counted from West to East 2. Zone 1 = 180°W - 174 °W 3. Each zone has a central meridian 4. Zone 1 Meridian = 177°W
How do you count sections in a Township? How many Sections in a Township?
1. A township USUALLY measures SIX MILES in size. The first six miles north of the base line is township one north written T. 1 N 2. 36 sections, 1 square mile
What Measurement level(s)?
1. Attribute quality, kind, type
Transverse Mercator slide 18
1. Attributed to Lambert 2. Transverse Cylindrical - rotate Mercator by 90° 3. Conformal - preserves shape 4. Narrow North-South strips 5. Very little distortion along Meridian 6. Globe gores - 30° wide in Longitude
State Plane Coordinate System (SPC) slide 4-7
1. East - West Orientation 2. Lambert Conformal Conic 3. Each zone projected with own Secant Case 4. conformal projection North - South Orientation 5. Transverse Mercator 6. Each zone with own Secant Case Projection 7. Attributed to Lambert 8. Transverse Cylindrical - Conformal (rotate Mercator by 90°) 9. Secant case along a central Meridian 10. Narrow North-South strips 11. Very little distortion along Meridian (120° W and 90 ° W) 12. Locating SPC positions • Coordinate Pairs (x,y) 13. 2 Origins established 14. 1. Easting - starts west of Central Meridian 15. 2. Northing - starts south of the zone • Zone Name 16. Lambert Conformal Conic: 2,500,000 m W of Central Meridian 17. Transverse Mercator: 500,000 m West of Central Meridian 18. Madison WI - Capital Building 2,164,600 ft E, 392,280 ft N Wisconsin, South Zone 19. Each zone is a separate entity on it's own 20. Difficult to use across zone boundaries 21. A better Grid has been developed, 22. Universal grid with global extent
Mollweide slide 21
1. Equal Area (akin to Peters) 2. Parallels unequally spaced - horizontal 3. Good for showing Global phenomena (elevation, below); 4. population, land cover, epidemiology
Sinusoidal slide 22
1. Equal Area projection 2. Equidistant along central meridian and in E-W directions 3. Used in atlases to show distribution patterns. 4. Has been used for maps of Africa, South America, areas 5. that are mainly north-south in extent. 6. Interrupted Sinusoidal 7. 3 meridians used
Mercator slide 16, 19, 20 24, 25
1. Equidistant from North to South, not East to West Cylindrical Conformal projection - Tangent Case 2. Continual widening of Meridians toward the poles 3. Increases area, maintains shape 4. Parallels increasing further apart away from line of Tangency 5. All lines of constant compass direction are straight lines on the map
How wide are the zones?
1. Extends from 84°N - 80°S 2. 6° wide, east and west
What is the significance of this Grid?
1. Stereographic (antipodal light source) 2. Scale increases away from center 3. Easting and Northing 2,000,000 mE 2,000,000 mN 4. 0° through the Greenwich Prime Meridian
Based off of the UTM system slide 1, 2
1. Locate USNG info on Topo: (available on topos printed since 2005) 2. Grid Zone Designation: 16T 100,000 m square ID (Palmyra, WI): CN 3. Use UTM grid coordinates to give location within a 1000 m square
What are the N and S Latitude extent covered by UTM?
1. Locating UTM positions 2. Coordinate Pairs 3. Grid Zone Number (1-60) 4. Capable of mapping a region of large North South extent with a minimal amount of East to West distortion
Grid Coordinate Systems Week 6 Lecture Notes - SPC, UTM, UPS URL slide 2, 3
1. Maps are spatial reference systems 2. Position of something in space in a relational frame of reference 3. Point Locating Systems 4. Use coordinates to define the position of grid intersection 5. X,Y locations on a coordinate plane 3 6. Cartesian Coordinates 7. Rene Descartes 8. 2D coordinates defined with respect to a single plane 9. Much easier to work with than Degrees Minutes and 10. Seconds (DMS)
Measurement level(s)?
1. Nominal (Qualitative) 2. Ordinal Ranked: Less than or Greater than No numerical value 3. Interval Arbitrary zero point Celsius and Fahrenheit scale 4. Ratio Zero starting point Kelvin Scale (temperature) - absolute zero Population Density, other statistical data
How does this work in the N hemisphere, and the S hemisphere?
1. Northern Hemisphere: Central Meridian easting value of 500,000 mE Equator northing value of 0 mN 2. Southern Hemisphere: Central Meridian easting value of 500,000 mE 3. Equator northing value of 10,000,000 mN 21
Robinson slide 23
1. Not conformal, equal area, equidistant, nor azimuthal 2. "Looks Right" - Compromise Projection - Orthophanic 3. Poles are horizontal lines (many-to-one locations) 4. Commonly used in National Geographic Cartography 5. Preferably used as classroom world maps
Lambert Conformal Conic slide 12, 13
1. Secant Case - Normal aspect 2. 2 standard parallels at 33°N and 45°N 3. Distortion at edge of map is <3% 4. Great circle routes are close to straight lines 5. Aeronautical Charts 6. Conformal 7. Great Circle Routes 8. Secant Case - Normal aspect 9. 2 standard parallels at 33°N and 45°N 10. Distortion at edge of map is <3% 11. Great circle routes are close to straight lines 12. Aeronautical Charts 13. Conformal 14. Great Circle Routes
Albert Equal Area Conic slide 13, 14
1. Secant Case - normal aspect 2. 2 parallels at 29.5°N and 45.5°N 3. Scale reduction <1% at 37°, 1.25% distortion at N and S ends 4. Most commonly used to map the U.S.A 5. Census statistical maps 6. USGS - geologic and tectonic maps 7. Satellite imagery mosaic Bipolar Conic 8. Made of 2 oblique conic projections
Universal Polar Stereographic System (UPS) slide 13-14
1. Secant Case - polar aspect 2. Complimentary to UTM; 84°N - 80°S 3. 30' overlap with UTM 4. (79° 30' 00"S - 90 °S) 5. North zone 6. South zone
Peters Equal Area slide 17
1. Secant case, Equal-Area projection 2. Distorts continental shape, elongation through mid and lower latitudes 3. Distortion shifted to the mid-latitudes, rather than the upper latitudes(as demonstrated with the Mercator Projection)
Qualitative Maps
1. Shows geographic distribution of a particular theme 2. Nominal level Information 3. In name only 4. In which category does a feature belongs 5.Order of the categories is not numerically significant 6. Points, Lines and Areas
Cylindrical Projections slide 15, 16
1. Tangent to any great circle 2. Central cylindrical light source 3. Light sources from center 4. Cannot project upper latitudes 5. Linear light source 6. Equal Area 7. Shape distortion and compression in polar regions 8. Normal Aspect (Equatorial) 9. Horizontal parallels of equal width 10. Equally spaced vertical meridians 11. 90° angles at latitude and longitude intersections 12. Transverse Aspect 13. Meridians are curved on the map, except for the line of tangency
Projection System used?
1. Transverse Aspect of the Cylindrical Projection SF = 1.0010 (.1%) outer edge at the equator
Lamberts Azimuthal Equal Area slide 11
1. World projection 2. Dart Board appearance 3. Equal spaced parallels 4. Meridians converge 5. Distance and direction are true only from center point of tangency 6. Common airport maps
Azimuthal Equidistant Week 6 Lecture Notes - Commonly Used Map Projections File resource slide 10, 11
1. direction of the point is preserved 2. The Plane surface is Tangent or Secant to a point on the globe 3. World projection 4. Dart Board appearance 5. Equal spaced parallels 6. Meridians converge 7. Distance and direction are true only from center point of tangency 8. Common airport maps
What are Correction Lines? Why are they important for this grid system?
1. one of a set of parallels of latitude 24 miles apart that is used for laying out nominally square sections and townships in the public land survey 2. because we are sectioning squares on a curved surface. Due to what is referred to as the convergence of meridians (distance allowance for the curvature of the earth), a correction line is required.
Conical Projections slide 12
1.Line of tangency along any small circle 2. Secant Case more effective, least distortion 3. 2 standard parallels 4. Best for mapping the mid-latitudes (20°- 50° N and S) 5. These regions fall within and on the standard parallels
Universal Transverse Mercator System (UTM) slide 8-12
2. Conformal, preserves shape 13. 3. North or South Madison WI - Capital Building 305,900mE; 4,771,650mN; Zone 16 North
Why is UTM considered universal and the SPC is not?
Capable of mapping a region of large North South extent with a minimal amount of East to West distortion
Quantitative thematic maps aggregated by Data collection units (areas) are called ____________.
Choropleth Data collection Methods 1. Statistical Data Population Counts 2. Physical Measurements 3. Sample Data
Projection System used?
Conformal projection
Fractional Divisions - ½ and ¼ only! No 1/3 or 1/8 or 1/16 slide 8, 9
Sections - 1 square mile Divided in: Halves or ¼ Sections W
main characteristics of each
chapter 5- Map projections
