Designing Maps GTECH201 Lecture 19

Yet Another Definition “A graphic depiction of all or part of a geographic realm in which the real-world features have been replaced by symbols in their correct spatial location at a reduced scale.”

Cartographic Design Principles Audience and purpose Size, scale, and media Visual balance

Audience and Purpose

Size, Scale and Media

Visual Balance

Elements of a Map Map body Legend Title Scale North arrow (inset map)

Other Elements of a Map Source of data Map projection Author Date Neatline Graphs, tables, images, informative text..leading towards a poster

Who Made It? What is its name? Legend Where is it located (inset)? Where is north What is the scale/ How accurate is it and where can you get it? Credits. How was it made. Projection and Datum. Other metadata UTM?? Coordinates in DD Border Neatline?

Map Templates

Layer Transparency

Labels and Annotation..more later today

Reference System Graticule ºN/S, ºE/W Measured grid X, Y Reference grid 12B or 14G

Map Layout Templates again

Map Scale The ratio of the distance between two points on the map and the distance between the same two points in the real world Describes distances and area sizes

Why Do We Care About Scale To compare or edge-match maps, they must be in the same GCS Remember, a GCS consists of: A metric An origin A projection A datum

Types of Scale Graphical Phrase (word(y) statement) Representative fraction Special cases Variable scale

Graphical Scale Changes in map size(copy machine) preserve scale relationships Unit independent

Verbal Scale Does not preserve scale with size change Unit-dependant One inch equals one mile One to a a mile

Representative Fraction Does not preserve scale in size change Unit independent Ratio is true regardless of units Expressed as a ratio1:100,000 Expressed as a fraction1/100,000

Variable Scale Projections that do not preserve distance City maps (Falk)

Large vs. Small Scale Small scale shows large areas Large denominator Think of it as small in detail Large scale shows small areas Small denominator Think of it as large in detail 1/500,000 1/500

Area and Scale Retains the same relationship as linear scale The linear scale is squared 1:1,000 2 equals 1:1,000,000 One square inch to one square mile

Examples of Scale

You Have to Decide What is the intended use How will it be used How much detail What are the units

Linear Units Metric Kilo-, centi-, milli-meters SAE Miles, yards, feet, inches Other Degrees, chains, furlongs, rods, light-years Unit-less

Areal Units Metric Hectare, decare, are U.S. Public Land Survey Township, section, acre Other City block, ZIP code, police district, parsec Unit-less

Convenient Fractions Metric 1 / 100,000 or 1 cm equals 1 km SAE 1 / 63,360 or 1 inch equals 1 mile U.S. topographic maps 1 / 24,000 or 1 inch equals 2,000 feet

Metric / SAE Conversion League1 Mile3 Furlong24 Chain240 Rod960 Yard5280 Foot15,840 Link24,000 Hand47,520 Inch190,100 Line2,281,000 Kilometer4.828 Meter4,828 Centimeter482,800 Millimeter4,828,000

Beware of 1 / 100,000 does NOT mean 1 mm equals 1 km, or 1 inch equals 100,000 feet Mixed units Not allowed in representative fractions Permitted in verbal usage

Resolution What is it that you wish to represent Countries States Counties Towns Property ownership

Detail How much information needs to be conveyed? How precisely have objects to be mapped? Generalization Cartographic license

Cartographic License Alteration of real-world spatial relations to better present pertinent information Distortion Combination Shift Exaggeration

How Much Detail?

Road Displacement

Generalization 1:5,000 1:10,000