# Computer Cartography midterm

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 Author: akatherine ID: 265168 Filename: Computer Cartography midterm Updated: 2014-03-09 13:24:03 Tags: Computer Cartography Folders: Description: LSU Computer Cartography midterm Show Answers:

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1. Dasymetric mapping
• first referenced in 1936 by J. K. Wright
• show densities of anything
2. intangible maps
• mental maps
• maps that you carry in your mind
• it can be drawn and converted to a tangible map
3. qualitative maps
• what is shown at a particular location
• they don’t display the quantity of item that can be found, just what is found
• can display names of areas
4. cartogram
• symbols are used but the size varies based on quantities
• distortion displays different types of data
5. enumeration unit rules
• block is considered to be the basic unit for the census, for privacy reasons
• there are larger units above it, like county and state
• 3 rules of thumb as to how many categories should be defined on a map breakdown
• 7±2 = 7-9
• 2x < n < 2x+1, where 2x = the largest value below the total
• Ex.: if total is 100 then 2x = 26 = 64
6. Choropleth map
• always use derived/standardized values
• Do NOT use absolute values or actual numbers
• Use derived values that only show rates, densities, or percentages
7. linear features
• Italic
• Blue
• Label should be on top of the feature, not bellow
• If it’s too long put the name multiple times
• On rivers use regular kerning
• If river is a polygon, apply polygon rules
8. Map titles
• in ALL CAPS
• Include area covered
• Time frame of the map
9. Class interval methods
• Equal steps
• Quantiles
• Arithmetic progression
• Geometric progression
• Optimal
• Natural breaks
• Standard deviation
10. Quantiles
• create classes with the same number of values in each class
• generic name for any number
11. Optimal
• Prefered method
• put values into a class that are very similar and each class is very different
• internal homogenous
• external heterogeneous
• default method used in ArcGIS
• good choice
• Chenks wrote an article in the 70s and defined the Chenks method
12. Natural breaks
• Prefered method
• Look for valleys, natural breaks (low points), in the frequency distribution
• Graphic array
• sort values by size and organize from smallest to largest
• apply the breaks where there is a difference
13. Proportional symbol mapping
• next to choropleth mapping it’s the 2nd most popular type of maps
• can map absolute and standardized values
• a symbol type is selected, usually a circle
• can map both aerial and point information
• centroid of the enumeration unit
• flexibility is higher
• can be collected for polygons or point locations
• different techniques used for proportional symbol mapping
14. proportional symbol mapping techniques
• absolute scaling (not used much any more)
• -   sizes of the symbols are mapped proportional to the quantities they represent
• -  need to know how to calculate the exact symbol type
• Apparent (magnitude) scaling
• -  lots of comparison between 2 different sizes
• -  developed based on the study of people’s interpretation of the sizes
• -  discussed in the article
• Range grading is used today
• -  Distinguish ability is very important
• -  usually the smallest circle is on top and larges is at the bottom
• -  can use numbers easily remembered, not easily remembered and ranges
• -  do not put more than 2-3 attributes on a map at the same time
15. Isarithmic map
• divided into 2 categories: isometric and isoplethic
• made by connecting points of the same value
• usually included in many GIS packages
• 3D representation of a surface
• Fishnet option
• can be rotated and angles can be changed
• east slopes are typically light, the west are dark
16. Isometric map
data is collected at points
17. Isoplethic map
data for areas
18. triangulation
• use of triangles to identify areas
• isolines need to be smoothed out
19. interpolation
• if there are different values they can be displayed in several ways
• foreground information should be displayed more prominently
• if the isaline is longer than label it more than once
20. Cartogram
• uses size and shape distortions
• no symbols
• no fill
• contiguous cartogram:  boundaries stay together as in reality just deformed
• non-contiguous cartogram:  boundaries are separated
21. 3 two-dimensional symbols used for proportional symbol maps
• circle
• triangle
• square
• proportional symbol map shows spatial numerousness
• dots should coalesce in densest parts of the map
• Classed and unclassed choropleth maps
• top is the 4 class conventional
• bottom unclassed
22. value-by-area cartogram
23. voluminous and bounded by continuous surface
24. Isarithmic map
25. Planimetric map: shows the model's surface
26. Thematic map with enumeration unit being a county
27. radial type of line map
28. network type of line map
29. distributive type of line map

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