MAP SCALE Scale varies across all maps  Pattern of scale distortion depends on map projection  Scale along line/point of SF = 1 (reference globe vs flat map) displayed in several ways: Representative fraction, or simple scale 1:100,000 or 1/100,000 Verbal statement – “One inch to 16 miles” Bar Scale Area Scale

REFERENCE SYSTEMS Some common, familiar reference systems: Dewey Decimal system for libraries Street addresses used by postal service Road map grids used by Rand McNally, etc. on travel maps Zip Codes for area reference Area Codes used by phone company for area reference

COORDINATE SYSTEMS Geographical coordinate system: S Older of two systems now in general use S Uses latitude and longitude to locate positions on the uniformly curved surface of the earth S Primary system – used for navigation and surveying Rectangular/plane coordinate systems: S Used for locating positions on a flat map S Evolved from cartesian coordinates applied to maps for for military purposes

COORDINATE SYSTEMS Cartesian Coordinates: è Originally devised by armies for easier computation of artillery trajectories è Defined by origin and unit of distance – basically a graph è Depend on Euclidean geometry

COORDINATE SYSTEMS Rectangular Coordinates: o Based on Cartesian coordinate system o Large scale maps typically use a conformal projection to maintain distance and direction calculations using rectangular coordinates o False easting and northings are typically added to coordinate values to keep coordinates in the upper right hand quadrant of the ‘graph’ – positive values o Most plane coordinate systems based on only these three conformal map projections: transverse Mercator, polar stereographic, Lambert’s conformal conic o Not used for small scale maps – too much distortion

COORDINATE SYSTEMS United States coordinate systems in common use: Universal Transverse Mercator Grid System Topographic maps, satellite imagery, natural resource databases, applications requiring precise positioning Uses meter as basic unit of measure Contains 60 narrow zones running N/S SF constant only along NS meridian of each zone Accurate overall to 1 part in 2500

COORDINATE SYSTEMS United States coordinate systems in common use: Universal Polar Stereographic Grid System Used to represent two circular polar zones not covered by UTM system SF is constant along parallels, which are circles in this projection Accurate overall to one part in 2500

COORDINATE SYSTEMS United States coordinate systems in common use: State Plane Coordinate System Devised in the 1930’s – plane rectangular coordinate system for each individual state Based on transverse Mercator or Lambert’s conformal conic projections; line of constant SF depends on which projection used Unit of measure is feet Overall accuracy to one part in 10,000

COORDINATE SYSTEMS United States coordinate systems in common use: Public Land Survey System Basic unit is areal, not linear – acre System is defined on the ground, not on a map grid Currently covers ¾ of land in the 50 states Baseline and meridian are defined on the ground and serve as origins System defines township, range, section Commonly used for legal descriptions of property

CARTOGRAPHIC DESIGN  Most design choices are compromises  Design as a process Stage one – imagination, creativity, graphic ideation > decide on type of map, size and shape, basic layout, data to be represented, mapping technique, etc. Stage two – specific graphic plan, most decisions made > kinds of symbolism, number of classes and class limits of data, color use, typographical relationships, line weights, etc. (often done on the fly using computers) Stage three – detailed specifications > define all symbols and line weights, colors, lettering size, etc.

CARTOGRAPHIC DESIGN Design as a product Does the map ‘look right’? Should be clear, simple, uncomplicated, and elegant Map should not look contrived Map should be aesthetically pleasing, while at the same time being thought provoking Does the map accurately and effectively communicate your message – the results of your data analysis? WHO IS YOUR AUDIENCE?

CARTOGRAPHIC DESIGN Basic Graphic Elements  Point – position  Line – direction and position  Area – extent, direction, position Primary Visual Variables  Shape – regular/geometric or irregular/pictographic  Size – length/height/area/volume – larger = more important  Orientation – lines/elongated shapes – need reference  Color (hue) – actual color (red, green, blue, etc.)  Color (value) – tone or relative lightness/darkness light = high value, dark = low value  Color (chroma) – saturation/intensity/richness/purity measured by how much gray is present

CARTOGRAPHIC DESIGN From Robinson, Sixth Edition, page 320 The Primary Visual Variables With some Examples of their Simple application To the classes of symbols

CARTOGRAPHIC DESIGN Types and symbols useful in quantitative mapping and their visual dimensions. Courtesy JP Publications. From Dent, Fifth Edition, page 78.

CARTOGRAPHIC DESIGN Secondary Visual Variables (pattern)  Arrangement – random or systematic shape and configuration of component marks that make up a pattern  Texture – size and spacing of component marks that make up a pattern  Orientation – direction arrangement of parallel rows of marks or parallel lines that make up a pattern

CARTOGRAPHIC DESIGN The Secondary Visual Variables with some examples of their simple application to the basic graphic elements. From Robinson, Sixth Edition, page 321

CARTOGRAPHIC DESIGN Symbol Classes Symbols should focus attention on what the symbol represents, not what the symbol looks like è Point emphasizing symbols: Dots, triangles, pictographs Denote position, location of feature, intensity at a place, representative location for spatial summary Examples: geographic coordinate location, radio tower, spot height, centroid of area distribution, conceptual volume (city population) Does not take up any geographical space

CARTOGRAPHIC DESIGN è Line Emphasizing Symbols Individual linear signs Depict rivers, roads, political boundaries Can also represent non-linear data such as elevation/depth/volume – contour lines May or may not indicate actual geographical size of features

CARTOGRAPHIC DESIGN è Area Emphasizing Symbols Indicate that region has some common attribute Examples include water, administrative jurisdiction, soil type, other homogeneous measurable characteristic Homogeneous nature depicted by even color or uniform repetition of point or line symbols (pattern)

CARTOGRAPHIC DESIGN è Volume Emphasizing Symbols Represent vertical or intensity dimension of spatial phenomenon through space Examples include terrain surfaces May be symbolized by color value (lightness) variations, spot height data, profile or contour lines