GEOG 3053 Quiz
Pros of 3D mapping
-Added information (extra dimension) -Improved positional accuracy (location) -Beneficial in showing complex information -More accessible to untrained readers -Helps to solve particular planning problems visually (ex. Viewshed analysis)
What is uncertainty?
-Determination of what is missing in the map; relative measure of the discrepancy between environment and its representation on the map -Doubt about information which is recorded at a location -A measure of the difference between the data and the meaning attached to the data by the current user -Result of error, ambiguity, vagueness, or lack of information
Cons of 3D mapping
-Difficult to produce - time and computation intensive -Scale inconsistent throughout the map -Topographic features can obscure important information
What has changed with the emergence of 3D mapping?
-Greater availability of digital data -Quicker and easier to process that data -Shift from producing static maps to dynamic and interactive map generation -Mapping more frequently takes place in the private realm of visual thinking
Visible variable use for mapping uncertainty
-If a visual variable used to show one aspect of data, cannot use the same variable to map another aspect. Cognitively impossible. -Same holds true for uncertainty - once used for data, the same visual variable should not be used for uncertainty - confusing in the same display
Sources of uncertainty --> storage
-Incorrection attribution (mis-classification) -Incorrect data paths (lost data links)
Sources of uncertainty --> collection
-Instrument limits/misfuntion (especially remote sensing) -Missing data
Augmented reality
-Live view of a physical environment with additional annotation projected into view -Combination of geolocation (GPS) and direct imagery (camera) -Increasing availability on mobile devices -Focus on new research in GIS and cartography
Sources of uncertainty --> data processing
-Most modeling/processing introduces uncertainties -Projection, generalization, estimation, prediction
sources of uncertainty --> use
-Type 1 Error: seeing wrong--> Seeing a pattern exists where none exists Type 2 Error: not seeing-->Missing a pattern which in fact exists Type 2 is more problematic type
Ways to map uncertainty
-Visualizing a type of uncertainty will depend on the -type of data associated with it -Types of data +Discrete (points and lines) +Categorical -Classed by aggregation, mosaicking, and overlay -Classed by partition +Continuous (surfaces and volumetric data)
What hasn't changed with the emergence of 3D mapping?
Effective cartographic design is still needed in new mapping environments
Uncertainty types
Positional: Locational error Attribute: Attribute error Logical: Geographic validity Completeness: Missing values Currentness: Temporality, initiation, duration, extinction, periodicity Lineage: Processing log or history
When to use separate vs merged displays for uncertainty
Separate: -Uncertainty has been processed by different method than data (ex. Data by classification, uncertainty by interpolation) -Spatial pattern of either data or uncertainty is very complex -Target map audience accustomed to working with uncertainty Merged: -Optimal visual variable is still available for displaying uncertainty -Data set is very familiar to users -Target audience has statistical expertise -Advanced visualization methods are available (glyphs, animation, interactivity, sound)
sources of uncertainty --> display
abstraction, symbolization
