Spatial Modeling

1
Spatial Modeling

• Spatial Models for Planning
• Map Composition
• Overlay and
• Boolean Logic

2
Overview

• Spatial Modeling
• Map Composition
• Begin Boolean Logic
• What we dont get to today, next Monday
• Quiz Monday

3
Spatial Modeling

• On the board with your help
• Exercise 5 as example

4
Steps to Creating a Map

• Purpose of map
• Restatement into a design problem
• Visualization to Creation
• Design solution - arrangement of maps image
  elements to facilitate communication
• Graphic design

5
Elements of a thematic map

• Title
• Legend
• Scale
• Credits
• Graticule
• Borders and neatlines
• Symbols
• Place names and labels

6
(No Transcript)
7
The elements one-by-one

• Title
• Draws attention by virtue of its size (big!)
• focuses attention on primary purpose of content
  of map
• not always needed
• Legend
• Principle reference to symbology
• MUST be there

8
The elements one-by-one

• Scale
• A MUST!
• Types
• graphic -- the bar
• verbal -- 1 1 mile (watch this one)
• a ratio 1/24,000 (this one too)
• Because of ubiquitous nature of Xerox machines
  the graphic scale is a must, the others are
  optional

9
The elements one-by-one

• Credits
• another, older, term for metadata
• Some metadata can be placed on map
• data source
• statement of accuracy, both spatial and attribute
• date data collected, date map made
• your name, assignment etc

10
The elements one-by-one

• Graticule
• a grid
• Often omitted
• useful if location info is important and there
  are no features like roads or steams

11
The elements one-by-one

• Borders and neatlines
• Optional
• Borders serve to restrain eye movement
• Neatlines are
• finer than borders
• drawn inside borders
• mainly decoration

12
The elements one-by-one

• Symbols
• can be actual symbols (style of city point)
  and/or colors and patterns
• most important part of map -- if user does not
  know what the symbolization is the map is useless
• Designer has little control over placement
  (location should be as accurate as possible given
  scale) but can control size and color

13
The elements one-by-one

• Place names and labels
• Primary means of communicating to user
• Orients user on map (similar to Graticule)
• Can provide important info re map purpose

14
Composition

• You have all the data (layers)
• You have the symbolization plan
• Now you have to visualize the map
• A creative process
• Trial and error process
• Where to put borders, neatlines
• what style of borders, neatlines

15
Composition

• Purpose of composition
• Forces designer or organize the visual material
• Stresses the purpose of the map
• Directs the users attention
• Develops an aesthetic approach for the map

16
Compositon Planar Organization

• Balance
• visual impact of arrangement
• is the map heavy at top, bottom, sides???

17
Visual weight

• depends on location
• obj near center has less weight
• obj weight increases with distance from center
• obj at top are heavier than those at bottom
• obj on right are heavier than those on left
• depends on size (Duh!)
• depends on color, interest, and isolation
• RedBlue, Brightdark
• complex simple
• isolated groups

18
(No Transcript)
19
Unequal divisions of space more interesting than
equal divisions
20
Which is better balanced?
21
Movement of readers eye - upper left to lower
right
Field
Focus
22
St. Louis too far from visual center, balance not
bad, however
Better, but a little heavy on right
23
Location of St, Louis
Legend -adf asdf adfafffdsf
24
(No Transcript)
25
(No Transcript)
26
Size / white space problems
27
Using Color

• Color is tricky
• There are definite color preferences
• There are definite color combination preferences
• There are standard color codes specific to
  profession

28
So

• Creating maps is a creating a document for a
  specific purpose -- to communicate something to
  the reader
• It is an iterative process
• There are some basic rules or guides that can be
  used

29
Map Composition for FOR556

• Title
• Legend
• Scale
• North Arrow
• Credits
• Borders
• Symbolization
• Balance

30
Overlay

• Overlay -- We have used some already and talked
  about it last Monday, but basically refers to
  functions involving two images to create a new
  one
• OVERLAY module in IDRISI as example can only
  handle two images
• So if you want to OVERLAY multiple images you
  have to combine them and take several steps
• CALCULATOR can do more than two at one time!

31
CALCULATOR

• In general CALCULATOR will work better/easier
  then OVERLAY
• Do several steps in one operation
• Can do very complex operations
• Can save these for future use/reference
• A more useful method of modeling uses BOOLEAN
  (a.k.a. Binary images ( 0 or 1 in image) -- But
  this doesnt solve all problems!

32
Boolean Logic

• Of or pertaining to an algebraic combinatorial
  system treating variables, such as propositions
  and computer logic elements, through the
  operators AND, OR, NOT, IF, THEN and EXCEPT.
• But, for us this means using true and false
  conditions with AND, OR, NOT, and XOR

33
Boolean Logic

• 1 true
• 0 false
• AND does the same thing as Overlay-Multiplication
  
• OR does the same thing as Overlay-Max
• max of 1s and 0s is 1
• NOT with one set of data reverses the set 1s to
  0s 0s to 1s

34
Boolean Logic

• XOR (a.k.a. Exclusive OR) all values that meet
  the pure condition of the first and second sets,
  BUT NOT both sets
• Not a very good explanation lets look at Venn
  diagrams

35
Whats Boolean processing
The AND function finds all regions where both and
only both of the input images have cells with 1s.
The OR function is true anywhere either or
both images are 1 NOT with two sets, is A AND(NOT
B) The XOR or exclusive OR function creates an
output image in which the cells are 1 wherever
either A or B are 1 but NOT where both A and B
are 1
36
Truth Tables
37
LOGIC
38
MULTIPLE OPERATIONS

• If you AND multiple images you get only the areas
  where 1 appears in ALL layers!
• If you OR multiple images you get only the areas
  where 1 appears in more than one image
• If you XOR multiple images you get only the areas
  where only 1 layer has 1s.

39
AND Acceptable areas
40
OR Acceptable areas
AOK OR SOK OR EOK OR WOK
41
XOR Acceptable areas
AOK XOR SOK XOR EOK XOR WOK
42
Order make a difference?

• NO, but use parenthesis to separate logic
  statements

AOK XOR EOK XOR SOK
AOK XOR SOK XOR EOK
43
Logical combinations
AOK AND ( SOK OR EOK)
(AOK AND SOK ) OR EOK
44
What about ADDing booleans

• In what way is the addition of the 4 binary
  levels better for decision making?
• 1 means ONLY 1 of the constraints was good
• 4 means all for were (best choice?)

AOK SOK EOK WOK
45
ADDing Booleans

• In what way is the addition of the 4 binary
  levels better for decision making?

46
How is this better?
AOK EOK10 SOK100
47
How is this better?
111 area where all 3 criteria are good 101 AOK
SOK criteria are good
111
101
110
AOK EOK10 SOK100
48
Boolean processing

• Make BOOLEAN images of acceptable areas
• AND them all together using CALCULATOR
• Result is a BOOLEAN image of OK areas
• ADD them all together using CALCULATOR
• What is result if, for example you have 4 such
  imgs?
• 0 where unacceptable, 1,2,3, or 4 where
  acceptable
• A side benefit - now you know how many factors
  were in the acceptable areas -- 4 has got to be
  good!
• Sometimes one method is better than another!

49
Summary

• Producing good looking and informative maps is
  critical
• Applying Boolean logic is the most efficient way
  to do site selection types of processing
• But is usually NOT the solution to the entire
  problem.