Lesson 9
Visualising and Analysing
Geographical Data
ISSS608 Visual Analytics and Applications
Content
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Introducing map
- Properties of geographical data
- Typology of map
- Thematic mapping techniques
- Alternative mapping techniques
What is a geographical dataset?
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
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Provides geographical location.
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Can be encoded explicitly in the dataset or need to be geocoded using location ID.
With explicit coordinates
Without explicit coordinates
Role of a map
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
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A map serves as a record.
Role of a map
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
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A map reveals spatial patterns.
Role of a map
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
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A map represents geographical data.
Role of a map
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
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An interface between geospatial data users and geospatial data.
Properties of Geographical Data
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
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Geospatial data models
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Geographical reference
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Geocoding
Properties of Geographical Data
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
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Geospatial data models
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Geographical reference
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Geocoding
Properties of Geographical Data
Geospatial data models
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
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Vector – implementation of discrete object conceptual model
–Point, line and polygon representations
–Widely used in cartography, and network analysis
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Raster – implementation of field conceptual model
–Array of cells used to represent objects
–Useful as background maps and for spatial analysis
Properties of Geographical Data
Vector Data Models
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
Properties of Geographical Data
Vector data models
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
Text
- Real world features and their spatial representations
Properties of Geographical Data
Georelational Vector Data Model
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
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Stores spatial and attribute data separately in a split system: spatial data (”geo”) in graphic fields and attribute data (“relational”) in a relational database
Properties of Geographical Data
Georelational Vector Data Model
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
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Simple vector data model: Shapefile
Properties of Geographical Data
Raster Data Models
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
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All raster formats are basically the same
–Cells organized in a matrix of rows and columns
–Content is more important than format: data or picture?
Properties of Geographical Data
Raster Data Models
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Google map
Properties of Geographical Data
Source of Digital Data
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Singapore
Properties of Geographical Data
Source of Digital Data
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- International
Properties of Geographical Data
Georeferencing
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Georeferencing means that the internal coordinate system of a map or aerial photo image can be related to a ground system of geographic coordinates.
- Two major families of georeferencing systems:
- Geographic Coordinates Systems
- Projected Coordinates Systems
Properties of Geographical Data
Georeferencing
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Geographic Coordinates Systems define locations on the earth using a three-dimensional spherical surface, for example, WGS84.
Properties of Geographical Data
Map Coordinates
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Commonly used geographic coordinates systems.
Properties of Geographical Data
Map Coordinates
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
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Projected coordinates systems: Any method of representing the surface of a sphere or other shape on a plane, for example, Mercator.
Properties of Geographical Data
Map Coordinates
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
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Two commonly used projection coordinates systems of Singapore.
Properties of Geographical Data
Map Coordinates
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Spatial referencing directory
Properties of Geographical Data
Map Coordinates
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- GDAL: gdaltransform, open source tool for transforming geospatial data from one projection to another projection.
Properties of Geographical Data
Geocoding
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Geocoding is the process of transforming a description of a location - such as a pair of coordinates, an address, or a name of a place - to a location on the earth's surface.
Properties of Geographical Data
Geocoding
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Creating geospatial-enabled data in Singapore
Properties of Geographical Data
Geocoding
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Structure of SLA's Address point Data
Properties of Geographical Data
Geocoding
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- SLA's Address point Data API
Properties of Geographical Data
Geocoding
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Some useful tips on using SLA's geocoding API.
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
Typology of Maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
Typology of Maps
Reference Maps
- Topography map
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
Typology of Maps
Thematic Maps
Qualitative
Quantitative
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Visual variables and cartographic symbols
Thematic Mapping
Qualitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Point symbol map
Thematic Mapping
Qualitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Line symbol map
Thematic Mapping
Qualitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Area or polygon symbol map
Thematic Mapping
Qualitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Multivariate symbol map, Chernoff Faces
Thematic Mapping
Qualitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Visual Variables and Cartographic Symbols
Thematic Mapping
Quantitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Proportional symbol map
- use different symbol size to represent attribute values
Thematic Mapping
Quantitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Proportional symbol map: Pie chart map
- use statistical chart to represent attribute values
Thematic Mapping
Quantitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Proportional symbol map: Bricks map
Thematic Mapping
Quantitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Dot Density Map
- use point of similar size to represent attribute values.
Thematic Mapping
Quantitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Chrolopleth map (area shading)
- Use different colours or patterns intensity to represent attributes values
Thematic Mapping
Quantitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- A un-classed choropleth map
Thematic Mapping
Quantitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- A classed choropleth map
Thematic Mapping
Quantitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Bivariate choropleth map
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Symbolized features based on more than one attribute
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Thematic Mapping
Quantitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Bivariate choropleth map
Thematic Mapping
Quantitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Cartogram
Thematic Mapping
Quantitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Cartogram of the world's languages
Thematic Mapping
Quantitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Cartogram in R
Thematic Mapping
Quantitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
Hexagon Binning Map
Thematic Mapping
Quantitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
Hexagon Binning Map using Tableau
Thematic Mapping
Quantitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
Bivariate Hexbin Map
Thematic Mapping
Quantitative maps
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
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Choose number of classes
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Data classification methods
Quantitative Mapping Considerations
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Sturges’ formula
- Number of intervals?
- Not less than 4
- To avoid an overly generalized map
- Not more than 12 colors
- 7 or 8 shades of the same color
Quantitative Mapping Considerations
Choose appropriate number of classes
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Equal Interval method divides the range of attribute values into equally sized classes.
Quantitative Mapping Considerations
Data Classification Methods
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Equal Count method assigns same number of features per class.
Quantitative Mapping Considerations
Data Classification Methods
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Natural breaks method using Default Jenk’s statistical optimization to find natural groupings in the data
Quantitative Mapping Considerations
Data Classification Methods
ISSS608 Visual Analytics and Applications
Lesson 9: Visualising and Analysing Geographical Data
- Standard deviation method, a measure of dispersion
Quantitative Mapping Considerations
Data Classification Methods
IS428 Visual Analytics for Business Intelligence
Lesson 9: Visualising and Analysing Geographical Data
- Colour brewer
Quantitative Mapping Considerations
Colour selection
IS428 Visual Analytics for Business Intelligence
Lesson 9: Visualising and Analysing Geographical Data
- Isopleth Map
Quantitative Mapping
IS428 Visual Analytics for Business Intelligence
Lesson 9: Visualising and Analysing Geographical Data
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Lines of equal value are drawn such that all values on one side are higher than the "isoline" value and all values on the other side are lower, or
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Ranges of similar value are filled with similar colours or patterns.
Quantitative Mapping
IS428 Visual Analytics for Business Intelligence
Lesson 9: Visualising and Analysing Geographical Data
Contour Map in ggmap of R
Lesson 9 Visualising and Analysing Geographical Data ISSS608 Visual Analytics and Applications
ISSS608-Lesson09
By Kam Tin Seong
ISSS608-Lesson09
- 893
