DATA OUTPUT  maps  tables

DATA OUTPUT output from GIS does not have to be a map many GIS are designed with poor map output capabilities types of output:  text - tables, lists number or text in response to query  graphic - maps, screen displays, graphs, perspective plots  digital data - on disk, tape or transmitted across a network  others (not common) - computer generated sound, 3D images

DATA OUTPUT Presenting Maps and Data  audience and information content  knowing your audience  knowing what information to present  showing data to the general public should be simple and easy to read  know your data  how many maps do you need?  how much detail do you need?  how many themes do you need?  how many features do you need?

DATA OUTPUT  concise title  topic, place, time  “Unemployment Percentages, Pittsburgh, PA 1990”  scale  direction indicator  north arrow - only for unusual orientations on large-scale maps  use geographic grid on small-scale maps  base map  information for visual locational reference

DATA OUTPUT Bad Map

VISUALIZATION TECHNIQUES  measurement scales  must facilitate interpretation of spatial objects and attributes  classification  how do we measure/organize things?  spatial: points, lines, areas, surfaces  measurement: ordinal, interval, ratio  are often subjective

ATTRIBUTE REPRESENTATION Graphic symbols  features shown on map can be differentiated and identified in various ways:  symbols  colors  sizes  labels (greatest flexibility)  considerations:  legibility, hierarchy, overlapping, balance

DATA OUTPUT  is appearance really important in a map drawn to support decision-making?  GIS output maps are to be used directly, not destined for walls or map libraries  should GIS products be simple, schematic, avoid high cost of manual cartographic quality? - NO

DATA OUTPUT Screen Display  issues are different because screen is:  smaller, lower resolution than a printed map  more flexible  principles of design of screen displays are poorly developed  black or white background? (color perception)  system is interactive, can display limited information but access to more  eg. user clicks on or points to an object

Text Output  perhaps more important than maps for reporting results of analysis  results might be a list or table of selected objectives with attributes  queries might result in numerical results (totals, distances, areas, counts)  text output might be delivered by a voice generator (navigation instructions - “turn left at next traffic signal” DATA OUTPUT

Reports on Layout select records to include generate a report add report to the layout DATA OUTPUT

Graphics on Layout select records to include create a graph and include on layout DATA OUTPUT

3-D display  some vendors are now offering 3-D stereo display devices  create the illusion of depth of rapidly switching between two images (left eye and right eye)  user wears eyeglasses containing clear polarizing filters  display must operate at images/second

GEOGRAPHIC INFO SYSTEMS

No Class on Wednesday Review on Friday Final Test on Monday and 2:30 – 4:30