1 Symbology The guts of making a decent map!

2 What’s in the module? explore a GIS map and get information about map features preview geographic data and metadata add data to a map describe the structure of a GIS map explain how a GIS represents real-world objects change the way features are drawn on a map access feature information in different ways describe spatial relationships of map features describe how GIS can be used to solve problems

3 What is important in the module? explore a GIS map and get information about map features preview geographic data and metadata add data to a map describe the structure of a GIS map explain how a GIS represents real-world objects change the way features are drawn on a map access feature information in different ways describe spatial relationships of map features describe how GIS can be used to solve problems

4 And imbedded in there is … Information on how to decide… –what you want to communicate to whom. –On the kind of classification to use to do that That’s why you need to read the stuff in the text and think about what you are doing in module 2.

5 An Important Concept “Many Factors affect the colors you choose. The perceptual structuring of the colors should correspond with the logical structuring in the data… Make sure the character and organization of the colors match the logic of your data…” 1 1 Cynthia Brewer, Designing better maps. ESRI Press

6 And… “When choosing map colors –you should not be overly concerned about which colors your audience likes. Everyone has an opinion … –It does seem that most people like blue and do not like yellow. – People like maps with many colors so focus your attention on presenting your data clearly using YOUR favorite colors.” 1 1 Cynthia Brewer, Designing better maps. ESRI Press

7 And… “When choosing map colors –you should not be overly concerned about which colors your audience likes. Everyone has an opinion … –It does seem that most people like blue and do not like yellow. – People like maps with many colors so focus your attention on presenting your data clearly using YOUR favorite colors.” 1 1 Cynthia Brewer, Designing better maps. ESRI Press

8 However Usually students don’t have to much trouble with making decent maps with reasonable symbolizations It comes naturally But you do need to keep some things straight when working with classifications of data And you usually have to classify

9 Data Types Nominal –are categorical data where the order of the categories is arbitrary Ordinal –categorical data where there is a logical ordering to the categories Interval –continuous data where differences are interpretable, but where there is no "natural" zero Ratio –continuous data where both differences and ratios are interpretable

10 ….more Quantitative data is numerical –Ratio, Interval, ordinal data types –continuous data – you are not limited to acuity of the eye –depth-to-bedrock (ratio) –Water table, pollution conc. Qualitative data is not necessarily numeric –Nominal data – soil type, road classification –limited to max of colors (classes) and you want contrast – 5 is better yet

11 Which on works better? Depends on the purpose of the map

12 Symbols Lots of symbols for points, lines, & polys Labeling features – –Dynamic and Interactive –Annotation Symbolizing based on attribute –Category –Quantity

13 Quantity Graduated colors –Color ramps – which work best? Graduated Symbols (classification) Editing legend entries for the TOC

14 Classification How many classes What method to use for placing the values into classes What kind of symbology to use (e.g., graduated colors or graduated symbols)

15 Maps - Categorical Categorical symbolization is typically used for NOMINAL data –Quite often similar colors will be used for related categories –You want the user to be able to discern the categories

16 Quantitative maps Displays quantitative data – interval or ratio data and even ordinal data A graduated ramp or palette is used

17 Classifications Natural breaks : finds groupings inherent in the data. Default Equal interval : interval between each class is the same. Quantile : each class contains an equal number of values (features). Manual : you decide

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19 The Well Designed Map… Has a single purpose! Size of paper and map scale determine the level of detail You cannot simply blow up a map from to something that would hang on the wall. A small map size will limit detail A large map viewed from a distance has same problem Reader must be able to easily interpret features Reader should be able to instantaneously understand the maps message

20 No Placenames ArcView Export screw up in 8.3! Only went to 3000 m in Layout! Too Much White Space!

21 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 (usually)

22 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

23 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…

24 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…

25 The elements one-by-one Mapped and unmapped areas –Objects, land, water, and other geographical features important to the purpose of the map –makes the composition a map rather than a diagram –The most prominent map element Graticule & Grids –Graticule – geographic coordinates

26 The elements one-by-one Borders and neatlines –Borders serve to restrain eye movement and focus attention on the map. A Border surrounds all the elements of a map. –A fill color can substitue for a border –Neatlines are: finer than borders drawn inside borders mainly decoration Used to highlight objects (like legends) and to help balance a map

27 Composition: Planar Organization Balance –visual impact of arrangement is the map “heavy” at top, bottom, sides??? Geometric center Visual center: 5% of total height above Geometric center -- Arrange content around this point

28 Visual weight Depends on location –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 –Red>Blue, Bright>dark –complex > simple –isolated > groups For Example …

29 Which is better balanced?

30 Which is better balanced?

31 Focus Field Movement of reader’s eye - upper left to lower right

32 Using Eye Movement Eye goes left to right Generally you want the reader to see the map BEFORE seeing the legend – can’t always do it

33 St. Louis too far from visual center, balance not bad, however Hard to read name Better, but a heavy on right Balance with legend etc.

34 Location of St, Louis Legend -adf asdf adfafffdsf

35 Location of St, Louis Don’t really need since countries are labeled

36 Size / white space problems Is this a better balanced map?

37 Summary of Guidelines 1)Map layout – where are the pieces going to go – major pieces – visual center – eye path – uneven juxtaposition of parts a)The map area and what’s in it b)Legend placement (usually to right of map) c)Scale bar, North Arrow d)Balance e)White space 2)Map Title – Large – may not be needed

38 Summary of Guidelines 3)Credits (Metadata) usually present 4)For FOR357/557- Author’s name, Exercise #, & date! 5)Borders and neatlines. a)Border around ALL map pieces or solid fill b)Neatlines (or fill) around (in) various pieces 6) Color – tricky – but not garish!

39 Booby Trap When you make scale bar it is grayed out? Why You didn’t set map and distance units No map units then ArcGIS has no idea what they are – probably no metadata If map units are m and you don’t want scale bar in meters then you have to set the distance units

40 Summary I have just covered the tip of the ice berg regarding symbols, color, and map design Even without intensive instruction in map design students tend to make decent designs Main problems are: –White space –Borders –Location of TOC