geobrowsers
' is not unrelated. These applications provide rich
spatial data sets and sophisticated and intuitive interfaces through which users can browse geographic information.
Introduction
This half-day tutorial has been designed to provide information visualization specialists with knowledge and skills in using geographic information techniques. Key issues in Geographic Information Science that are fundamental to effective geovisualization will be highlighted and accessible technologies used to develop example applications.
Topics will be introduced by an instructor before you complete a short task that allows you to build a geovisualization application from diverse data sources. You will need access to a notebook computer and will be asked to install freely available software in preparation for the 'hands on' element of the tutorial.
Level: 'beginning' - no specific prior knowledge is expected.
No prior experience with using geographic information or GIS is assumed. No programming skills are required.
Visualization and Cartography
Visualization is widely regarded as a process that involves developing and using visual representations of data to generate ideas and knowledge about phenomena of interest.
Geographic sciences have a long tradition of using graphical depictions of data to help prompt insights and to explain phenomena that vary spatially. The most famous example is perhaps John Snow's mapping of the locations of cholera deaths in Soho. The spatial relationships between these points and the locations of water pumps helped to establish the water-borne nature of the disease. Edward Tufte (Tufte 1997) reports this particular example, but many others exist.
The 'art and science' of cartography provides a knowledge base that has been used to help those in the geosciences with their visualization. This has been developed through experience, preference, empirical evaluation and a deep understanding of the nature of geographic phenomena. It has led to a number of established approaches and conventions.
Significant efforts are currently going in to the development of highly interactive interfaces that support visualization
through the repeated
process described by Ben Shneiderman as :
"Overview first, zoom and filter, then details-on-demand" (Shneiderman 1996)
Researchers in computer science and the geographic sciences are participating in this effort.
Much of the knowledge developed in cartography applies to the static domain, but some is relevant to visualization - particularly when visualization involves geographic phenomena or spatial metaphors (Skupin 2000).
Geographic and Georeferenced Data
As data volumes in general increase georeferenced data are more widely collected and available. Spatial data that is centrally
developed through a
'top-down' approach, such as that recorded by governments through formal means (for example via a census of population), is
increasingly accessible
online. Equally, user contributed spatial data, whereby users informally generate content with georeferences in a 'bottom-up'
manner, is increasing
in volume. The development and popularity of 'geobrowsers
' is not unrelated. These applications provide rich
spatial data sets and sophisticated and intuitive interfaces through which users can browse geographic information.
In turn these various trends are resulting in opportunities for visualizing geographic information and the need to use a geographic framework to organise data so that we can:
Geovisualization
Geovisualization provides tools and techniques to support this activity. It is a process in which interactive visual approaches are used to help synthesize data from different sources and explore data sets that are based upon a common geographic framework. These approaches can help us generate ideas by identifying spatial relationships - both within phenomena (that may relate to spatial trends, errors, anomalies, or issues of data integrity) and between phenomena (that may lead to ideas about cause and effect - as was the case with John Snow - or suggest that relationships vary geographically).
Various tools and frameworks exist to support geovisualization and geobrowsers
offer some opportunities. Many use
open, well documented data formats and contain applications programming interfaces.
In this tutorial we will explore some techniques for using the Google Earth
geobrowser
as a tool for geovisualization and use a Geographic Information System (GIS)
to transform and display our data.
On completing this tutorial you will be able to do the following :