18_Intro_map_making2

18_Intro_map_making2 - We now know: 1.How to measure the...

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Unformatted text preview: We now know: 1.How to measure the location of geographical features of interest 2.How to store these features in a GIS using data structures 3.How to gather data about these feature and, thus, “populate” the data structures we learned, and 4.How to assess the accuracy of these data 5.Now- onto how to display geographical features using GIS Making Maps With GIS Making The Parts of a Map The Choosing a Map Type Designing the Map Designing What is a map? What s “A graphic depiction of all or part of a geographic realm in which the real-world features have been replaced by symbols in symbols their correct spatial location at a reduced scale.” scale power line Map functions in GIS Map s s s s s Storage Communication Intermediate check of data Analysis Final report To be effective, maps must be correctly designed To and constructed. and The Need for Design The To appear professional and avoid errors, To GIS maps should reflect cartographic knowledge about map design. knowledge s A map has a visual grammar or structure map that must be understood and used if the best map design is desired. map s Cartographic conventions exist and should Cartographic be respected (e.g. forests should be green). be s General reference maps Thematic Maps The Parts of a Map: Map Elements The Border Neat line Title The United States of America Figure Legend Ground Alaska 01234 Hawaii 04 Inset Scale Washington,D.C. National Capital hundreds of kilometers 04 Place name Lambert Conformal Conic Projection Source: U.S. Dept. of State North Arrow Credits Ground Figure Border & Neatline Border Visual stability Scale Scale Graphic scale = Map units Ground units Verbal scale Representative fraction s Insets –Scale down for Scale regional context regional –Scale up- to add detail Scale In this case Africa is being placed in a broader geographical context with respect to the subject of the map. sTitle Map “impact” Map what’s the best title? s Distribution of Employment by State 1996 s USA: Employment Distribution 1996 s U.S. Employment: 1996 Distribution s America at Work s Where the Jobs are Today sText Selection and Placement Selection k POINT LINE e ud M La BM 232 NV CA 20 0 New York SR U 66 ute o AREA Figure 7.2 Some cartographic label placement conventions. Points: right and above preferred with no overlap. Lines: Following the direction of the line, curved if a river. Text should read up on the left of the map and down on the right. Areas: On a gently curved line following the shape of the figure and upright. sGraticule/Grid sText Legends Legends 0-50 50-100 100-1000 Choosing a Map Type Choosing Cartographers have produced many map Cartographers types: methods of cartographic representation. representation. s Not all GISs allow all types. s Most have a set of basic types s Choosing the Wrong Type Choosing Fairly common GIS error. s Due to lack of knowledge about Due cartographic options. cartographic s Can still have perfect symbolization. s Possibility of misinformation s Definite reduction in communication Definite effectiveness. effectiveness. s “There are lies, damn lies, and maps” A Mark Twain, Mark Monmonier “mash-up” http://en.wikipedia.org/wiki/Mark_ Twain http://www.markmonmonier.com/ Map Types: Point Data Map Topographic s Dot s Picture Symbol s Graduated Symbol s Reference s Location, magnitude, density… Map Types: Line Data Map Network s Flow s Isopleth s Reference s Location, connectivity, surfaces Map Types: Area Data Map Choropleth s Area qualitative s Stepped surface s Hypsometric s Dasymetric s Reference s Location, magnitude, density, surfaces Map Types: Volume Data Map Isopleth, Stepped Surface, Hypsometric s Gridded fishnet s Realistic perspective s Hill-shaded s Image map s Map Types: Time Map Multiple views s Animation s – Moving map Choosing Types Choosing s s s s s Check the data – Continuous (e.g., topography) – Discrete (e.g., associated with political or enumeration Discrete districts) districts) – Accuracy & Precision- detail often implies accuracy Accuracy – Reliability Dimension (Point, Line, Area, Volume) Scale of Measurement (Nominal, ordinal, interval, ratio) GIS capability May need to supplement GIS software The Design Loop The Create map layout s Draw on screen (proof plot) s Evaluate s Edit s Repeat until happy s Make final plot s Map Design Establishment of context and figure-ground relationships helps the reader of the map. Don’t work against the reader; make it easy for them to see your point. Have an attitude: this is my map and I want the reader to see my point. You can manipulate map elements to bring the item or area of focus to the attention of the map reader (percipient!). In “A” if there were no typography (textual info), the lines would be ambiguous. Adding shading to distinguish figure and ground provides focus. You can manipulate map elements to bring the item or area of focus to the attention of the map reader (percipient!). In “A” if there were no typography (textual info), the lines would be ambiguous. As details are added (“B” & “C”) the context of map becomes more clearer. Map Design Establish a visual hierarchy. Decide what elements are most important and place them as figure. Other elements are the backdrop. Poor visual hierarchy Establish a visual hierarchy. Decide what elements are most important and place them as figure. Other elements are the backdrop. Map Design Map Map Design Map s Visual balance is affected by: Visual is – the "weight" of the symbols – the visual hierarchy of the symbols and the elements elements – the location of the elements with respect to each the other and the visual center of the map. other A B C D E F Visual center Visual 5% of height 5% of height Landscape Portrait Visual Layout Visual A Title Here B Title Here Eye expects (1) balance and (2) allignment Scale and Generalization Scale Smaller scale means fewer features (selection). s Smaller scale means smoother features Smaller (simplification). (simplification). s Smaller scale means combining features Smaller (aggregation). (aggregation). s Smaller scale means displacing features Smaller (displacement). (displacement). s Scale and Generalization Scale s Often scales are mixed in the context of Often GIS- what does that mean to you as an analyst? analyst? Map Design and GIS Map When a GIS map is the result of a complex When analytical or modeling process, good design is essential for understanding. is s The map is what distinguishes GIS as a The different approach to the management of information, so extra care should be taken to improve the final maps that a GIS generates in a GIS task. generates s ...
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This note was uploaded on 04/01/2012 for the course 044 005 taught by Professor Davidbennett during the Fall '11 term at University of Iowa.

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