Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Making Maps with GIS The Parts of a Map Choosing a Map Type Designing the Map

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) What is a map? “A graphic depiction of all or part of a geographic realm in which the real-world features have been replaced by symbols in their correct spatial location at a reduced scale.” power line

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Map functions in GIS Storage Temporary communication Intermediate check of data Final report To be effective, must be correctly designed and constructed.

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) The Parts of a Map: Map Elements The United States of America Alaska Lambert Conformal Conic Projection Source: U.S. Dept. of State hundreds of kilometers Washington,D.C. National Capital Legend Scale Credits North Arrow Place nameInset Ground Figure Neat line BorderTitle Hawaii

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Cartographic Elements Border Neatline Insets –Scale up –Scale down Metadata e.g. index Off-map references

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Cartographic Elements Page coordinates Ground elements Graticule/Grid North arrow

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Cartographic Elements Figure –Point/Line/Area symbols –Text –Place Names –Title

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Cartographic Elements Reference Information –Scale –Projection(s) –Sources (2) –Credits –Legend –Reliability

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Map “impact” Distribution of Employment by State 1996 USA: Employment Distribution 1996 U.S. Employment: 1996 Distribution America at Work Where the Jobs are Today

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Text: Selection and Placement New York BM 232 U S R o u t e L a k e M u d POINTLINEAREA CA NV

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Choosing Elements Map research Map compilation Worksheet Selection Placement Layout Tools in GIS not ideal

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Choosing a Map Type Cartographers have designed hundreds of map types: methods of cartographic representation. Not all GISs allow all types. Most have a set of basic types Depends heavily on the dimension of the data to be shown in the map figure.

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Choosing the Wrong Type Fairly common GIS error. Due to lack of knowledge about cartographic options. Can still have perfect symbolization. Possibility of misinformation Definite reduction in communication effectiveness.

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Map Types: Point Data Reference Topographic Dot Picture Symbol Graduated Symbol

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Mapping features conceived of as points Conceived spatial structure –exist as points –are referenced to points –are conceived of as points for mapping purposes Levels of measurements –qualitative -- nominal –quantitative -- ordinal, interval, or ratio Symbolized with point marks

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Symbolizing qualitative point data Show the location of features without implying a message of magnitude nominal scale data appropriate visual variables –differentiating primary variables shape hue orientation –can you use secondary variables? Pattern arrangement, pattern orientation

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Qualitative point maps Examples –hue –shape –orientation –pattern arrangement –pattern orientation highly pictoral geometric symbols mimetic symbols Level of generalization Q dx u v w

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Symbolizing quantitative point data Show the location of features while implying a “message of magnitude” ordinal, interval, ratio scale data appropriate visual variables –ordering primary variables size value chroma –can you use secondary variables?

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Quantitative point maps Examples –Size –Value –Chroma –Pattern texture –Combinations: size and value (Usually used together)

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Graduated Symbol Map

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Graduated symbol maps -- objective Also called “proportional symbol” maps Symbol size varies from place to place in proportion to the quantity it represents Two types –proportional -- size represents actual data values –Classed – size represents classes of values range graded -- size class represents a numeric range of data (e.g., 1-10, 11-20, 21-30, 31-40, 41-50) ordinally scaled -- size class represents a descriptive group (e.g., low, medium, high)

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Graduated symbol maps – methods Graduated circles often used because of –compact geometric form –ease of scaling –visual stability (less eye wandering)

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Scaling Graduated Symbol Maps Scaling determines the size of the symbols Adjustments to scaling are sometimes made –area is increasingly underestimated as higher magnitudes of the stimulus are judged Therefore, symbol sizes are adjusted to compensate for underestimation Methods for scaling circles –Square root method -- based on the area of the circle –Psychological scaling -- scales to reflect underestimation by map users ValuesRadii 500, , , , ValuesRadii 500, , , ,

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Graduated symbol maps -- methods 1.Create area proportional circles using the circle radius equation 2.Scale circle area to square root of the data or scale proportional symbols to accommodate human perception of symbols 3.Couple size with another ordering visual variable (value) 4.Show a second distribution with another ordering visual variable (value) 5.Provide legend for symbology 500, , ,000 50, ,000 to 500, ,000 to 250,000 50, 000 to 100,000 0 to 50,000 very large large medium small 500, , ,000 50,000

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Picture Symbol Map

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Map Types: Line Data Network Flow Isopleth Reference

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) General Purpose: Reference Maps Network map –shows set of connected lines w/similar attributes e.g., subway, bus/airline routes, streams/rivers Flow map –similar to network map, but line width varied to show value

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Simple Flow Map

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Flow Map with Graduated Symbol

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Map Types: Area Data Choropleth Area qualitative Stepped surface Hypsometric Dasymetric Reference

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Thematic Maps Choropleth map –data classified and grouped within areas such as states or counties; shaded according to value Area qualitative map –simple color or pattern applied to area types e.g. land use classes: residential, agricultural, forest, wetland, tundra, water

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Choropleth Map

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Area Qualitative Map: Land Use

Area Qualitative Map

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Map Types: Volume Data [Isopleth, Stepped Surface, Hypsometric] Gridded fishnet Realistic perspective Hill-shaded Image map

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Volumetric Data Maps Stepped statistical surface –block type diagram in perspective Isoline map –consists of lines joining points of equal value; surface continuity is assumed Contour interval map (contour map) –isoline map indicating terrain changes; e.g., meters or ft between contour lines

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Stepped Statistical Surface Map

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Colored Isoline Map

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Shaded Contour Map

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Choosing Types Check the data –Continuous –Discrete –Accuracy & Precision –Reliability Dimension (Point, Line, Area, Volume) Scale of Measurment (Nominal etc.) GIS capability May need to supplement GIS software

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Data Scaling (Stevens) Nominal (Name of a place) Ordinal (Small, med., large town) Interval (Arbitrary zero e.g. Sea Level) Ratio (Absolute zero e.g. dollars, densities)

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Example: Choropleth Mapping Data should be AREA (e.g. States) Data should not suffer from area effect. Population? Per capita Income? Elevation? Temperature? Boundaries unambiguous. Areas non-overlapping.

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Classification Equal Interval Natural groups N-tiles Equal or unequal? Logarithmic? Linear? Discontinuous? How many classes? Non-overlapping, distinctive groups.

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS)

The Need for Design n To appear professional and avoid errors, GIS maps should reflect cartographic knowledge about map design. n A map has a visual grammar or structure that must be understood and used if the best map design is desired. n Cartographic convention (e.g. forests should be green).

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Map Design A GIS map is designed in a process called the design loop. Good map design requires that map elements be placed in a balanced arrangement within the neat line.

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) The Design Loop Create map layout as macro Draw on screen (proof plot) Look Edit macro Repeat until happy Make final plot

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Graphic Editors

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Graphic Editor Software Vector –Adobe Illustrator –CorelDraw –Freehand Raster –Photoshop –CorelPaint –Fractal Paint

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Map Design (2) Visual balance is affected by: the "weight" of the symbols the visual hierarchy of the symbols and elements the location of the elements with respect to each other and the visual center of the map.

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Visual center 5% of height Landscape Portrait

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Visual Layout Title Here Eye expects (1) balance and (2) allignment

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Symbol “weight” Line weight Pattern ShadingHue

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Color and Map Design Color is a complex visual variable and in a GIS is specified by RGB or HSI values. Red, Green, Blue are additive primaries. Magenta, Cyan and Yellow are subtractive primaries. Saturation and Intensity map better onto values than hue.

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Dimensions of Color HUE SATURATION INTENSITY

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Simultaneous Contrast

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Color Primaries Subtractive color Additive color

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Text placement Santa Barbara L a g o o n Path right PathDownPathDown

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Scale and Generalization Smaller scale means fewer features. Smaller scale means smoother features. Smaller scale means combining features. Smaller scale means displacing features. Often scales are mixed or overgeneralized.

Introduction to Mapping Sciences: Lecture #6 (Creating Maps in GIS) Map Design and GIS When a GIS map is the result of a complex analytical or modeling process, good design is essential for understanding. The map is what distinguishes GIS as a 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.