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Geographic Information Systems SGO 1910, 4930 November 8, 2005. Announcements. eSeminar in GIS: Putting the e into GI Science (Mark Birkin, Leeds). Thursday, November 17, room 3514 Georg Sverdups Hus.
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Geographic Information SystemsSGO 1910, 4930November 8, 2005
Announcements • eSeminar in GIS: Putting the e into GI Science (Mark Birkin, Leeds). Thursday, November 17, room 3514 Georg Sverdups Hus. • Norsk ESRI brukerkonferanse 2006Den 17. norske ESRI brukerkonferansen går av stabelen 1. -3. februar 2006. Konferansen byr på en rekke foredrag, tekniske minikurs, bransjeseminar og sosiale aktiviteter. Vi ser frem til spennende dager sammen med deg! Påmelding og mer informasjon kommer senere.
Announcements • Extended access to GIS lab during Nov.-Dec? • GIS Internships: Any interest?
Oslo Project Groups • Marita Sanni, Kristin I. Dankel, Solveig Melå + Svein Johan Hansen? • Åslaug Enger Olsen, Maria Lyngstad, Guro Bakke Håndlykken og Jorunn Randby (4) • Nina Ambro Knutsen, Ellen Winje og Leif Ingholm, Gjermund Steinskog (4) • Birte Mobraaten, Hans Petter Wiken, Silje Hernes and Bente Lise Stubberud (4) • Daniel Molin, Ida Sjølander, Anne-Lise Folland and Nicolai Steineger (4) • Hæge Skjæveland, Marie Aaberge, Cecilie Hirsch, Kaja Korsnes Kristensen (4) • Urs Dippon, Steven huiching Yip, Harald Kvifte & Eirik Waag (4) • Marthe Stiansen, Marielle Stigum, Tomas Nesset, Andreas Skjetne (4) • Andreas Dyken, Håkon Grevbo, Terje-Andre Gudmundsen, Øystein Kristiansen (4) • Andreas Wilhelm Westgaard, Grete Simensen og Ingvild Jøranli, Solveig Lyby (4) • Linda Markham, Marte Hunsdal Knutsen, Anette Nesvold, Berit Indset (4) • Magnus Campbell, Johannes Devik Brekke, Espen Fait, Mathias Ødegård (4) • Julie Aaraas, Tonje Einarsen, Anne Marie Skancke, Bård Bergland (4)
Introduction • Output is the pinnacle of GIS projects • Two main types of output • Maps • Visualizations (see chapter 13) • Maps are good at summarizing and communicating
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 • “A graphic depiction of all or part of a geographic realm in which the real-world features have been replaced by symbols in their correct spatial location at a reduced scale.”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
Map function in GIS • Storage • Temporary communication • Intermediate check of data • Final report
Characteristics of Map • Two main types • Topographic • Thematic • Some map problems • Can miscommunicate • Each map is just one of all possible maps • Complex maps can be difficult to understand
Map Types • Point data • Line data • Area data • Volume data • Time data
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.
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.
Choosing Types • Check the data • Continuous • Discrete • Accuracy & Precision • Reliability • Dimension (Point, Line, Area, Volume) • Scale of Measurement (Nominal, ordinal, etc.) • GIS capability • Is there a need to supplement GIS software? (e.g. with a drawing package)
Maps and Cartography • Map – ‘digital or analog output from a GIS showing information using well established cartographic conventions’ • Cartography is the art, science and techniques of making maps
The Need for Design • To appear professional and avoid errors, GIS maps should reflect cartographic knowledge about map design. • A map has a visual grammar or structure that must be understood and used if the best map design is desired. • Cartographic conventions should be followed (e.g. forests should be green).
Map Design • Good map design requires that map elements be placed in a balanced arrangement within the neat line. • A GIS map is designed in a process called the design loop.
To be effective, a map must be correctly designed and constructed.
The Parts of a Map: Map Elements Border Title Neat line The United States of America Figure Legend Scale Ground Washington,D.C. National Capital Alaska 0 1 2 3 4 Hawaii hundreds of kilometers 0 4 Lambert Conformal Conic Projection 0 4 Source: U.S. Dept. of State Inset Place name Credits North Arrow
Inset map Scale Author North Arrow Data Source Map Body Projection Legend Grid Title
Visual balance is key! • 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.
Visual center 5% of height 5% of height Portrait Landscape
Title Here Title Here Visual Layout Eye expects (1) balance and (2) alignment
0 0 Text: Selection and Placement 6 6 e t u o R S d U u M Kristiansand e k 2 a Bærum L Oslo BM 232 POINT LINE AREA Some cartographic label placement conventions. Points: right and above preferred with no overlap. Lines: Following the direction of the line, curved if a river. Areas: On a gently curved line following the shape of the figure and upright.
Text placement Trondheim Trondheim Path right Trondheim P a t h D o w n Trondheim Bogstadvann
Shading Hue Pattern Line weight Symbol “weight”
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.
Limitations of Paper Maps • Fixed scale • Fixed extent • Static view • Flat and hence limited for 3D visualization • Only presents ‘complete’ world view • Map producer-centric
Conclusions • Cartography is both an art and a science • Maps are fundamental to GIS projects • Modern advances in cartography make it easy to produce good and bad maps • New technology and especially the Internet has change the content and techniques of GIS-based cartography