4 Map as CommunicationGoal is to capture the spatial character of particular area and help the user to understand the geographic relationshipsThe principal task of cartography is to communicate environmental information. The task of the map designer is to enhance the map user's ability to retrieve information.
5 Map as Communication Maps perform two important functions: Storage medium for information that humanity needsProvides a picture of the world to help understand spatial patterns, relationships, and environmental complexity
6 Cartographic Basics Maps tell us: What is it? (often) When is it? Where is it?What is it?(often) When is it?What is nearby? How far away? In which direction?How do I get there?What other things are there also?How might they be related?Location - position in two-dimensional spaceAttributes - qualities or magnitudes such as language or temperatureReduction of reality - obviously cannot map at 1:1, thusScaleTransformations - from round earth to flat map or screenAbstractions - only some environmental information can fit on any given map. Information is subject to classification, simplification and perhaps other operations to make it easier to portray and understand.Symbolism - signs stand for elements of reality.
7 Understanding the Environment Represent real world features TangibleIntangibleSimplified/Categorized
10 Cartographic Basics Basic characteristics of all maps: Location AttributionReduction of realityScaleGeometrical transformation/projectionAbstractions of realitySymbolism
11 Cartographic BasicsLocation and Attribution allow many types of relationships to be formed:Relationships among locations with no attributes –distance, bearingRelationship among various attributes at the same pointRelationship among different locations of the same attributeRelationships among locations of combined/derivedattributes of given distributions -- spatial distributionof per capita income vs. educational attainmentGet 'standard' fractions for each scale.General reference - topo maps - show the locations of a variety of different features such as water, coastlines, roads.Thematic - distribution of a single attribute or the relationship among several attributes. Precipitation, cloud cover, average annual income, population, etc.Charts - designed for nautical and aeronautical navigators. Charts are to be worked on rather than looked at. Plot courses, determine position, mark bearings, etc. Road map could be thought of as a chart for land navigation.Cadastral - official land holdings and property owners; land parcels; used for tax assessment.Plans - large scale detailed maps showing buildings, roadways, property lines, etc. Used for urban planning.
12 Cartographic Basics Classification of maps: Classed by Scale Small scaleMedium scaleLarge scaleClassed by FunctionGeneral reference mapsThematic/special purpose mapsChartsClassed by Subject MatterCadastral mapsPlansSoil, vegetation, precipitation, etc.
13 Cartographic Basics Mapping involves information transformations: Data collectionSelectionClassificationSimplificationExaggerationSymbolizationUse of mapData collection - where did your data come from? Census, ground survey, remote sensing, compilation of other data.Selection - not all data can be presented on every mapClassification - how is your data broken up for viewing? How many categories of population size? What level is your soil survey?Simplification - very sinuous roads or rivers cannot be depicted accurately - they are straightened for mapping purposesExaggeration - a small stock tank is much smaller than the dot on the map that represents itSymbolization - water=blue, forest=green. What color are cows? What shape is precipitation?Use of map - depends on users skill in map reading, analysis, interpretation.1)may be done for you2)most time consuming3)the best way to find errors/poor design/omissions - never leave this out4)if you can't read your own map, will anybody else be able to?
14 A Brief History of Mapspre 2000 B.C. Earliest direct evidence of mapping comes from the middle east. These ancient Babylonian clay tablets depict the earth as a flat circular disk.Ancient Chinese Maps In ancient times, Chinese cartography was more advanced than their contemporaries'. Their maps were accurate and detailed compared to other ancient maps.200 B.C. The Greeks understood that the earth was a sphere. Eratosthenes accurately calculated the circumference of the earth using angle measures.
22 A Brief History of Maps (cont.) 150 A.D. Ptolemy defined in Geography the elements and form of scientific cartography. In spite of his errors (he maintained that the sun revolved around the earth, and calculated the earth as 3/4 its actual size), Ptolemy was far ahead of his time on how scientific research should be conducted. He proposed a system of projections and coordinate systems that are still used todayMiddle Ages European maps were more ecclesiastic than cartographic. Cosmas exemplified this concept, incorporating religious themes and references into many of his maps. In contrast, Arab maps advanced the earlier Greek practices. Al-Idrisi designed a still- famous world map.
31 A Brief History of Maps (cont.) 16th century Mercator created a map- the Mercator Projection that allowed mariners to sail to their destinations by following a fixed rule called a rhumb line.17th century Newton postulated that, due to the centrifugal force of the spinning earth, strongest at its equator, the earth bulges at the equator and flattens at the poles. The earth is not a true sphere, but a spheroid.
37 A Brief History of Maps (cont.) 19th century Europeans implemented the metric system which introduced a simpler and more universal language for map scale. The Greenwich prime meridian was established20th century Aerial photographs, computers, electronic distance-measuring instruments, inertial navigation systems, remote sensing, and applications of space science create new extensions of cartography's reach. The Internet makes that reach accessible to all of us.