May 24

yardbellAI and Robotics

Nov 14, 2013 (3 years and 6 months ago)

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Geography 360

Principles of Cartography

Recent Developments in Cartography

-

Geographic Visualization

-

May 24, 2006

Outlines

1.
Introduction

2.
Map Animation


Categories of map animation

3.
Data Exploration


Exploratory Data Analysis


Methods for data exploration

4.
Virtual Environment


Virtual Reality


Geospatial Virtual Environment

5.
Conclusions

1. Introduction


Recent developments in cartography can be understood
in the context of overcoming the limitation of traditional
cartography (e.g. static paper map) while meeting
present & future needs



We will call the recent developments in cartography
“geographic visualization” or GeoViz



In this lecture, we will focus on map animation, data
exploration, and virtual environment

Limitations of static map


Some map shows change over time


e.g. map for learning climate change


Animation



Some map requires high degree of user interaction


e.g. maps that vary by criteria in multicriteria decision process


Data exploration



Some map needs to offer realistic impression of the
environment


e.g. maps for depicting the effect of new urban development


Virtual reality

Present & future needs for map


Think how maps are used these days



Growing needs for use of maps for data analysis,
enquiry process and decision support redefine
roles of a map


Map as a tool for facilitating pattern
-
seeking and
hypothesis formulation



How should we design the map given changes
in the nature of demands for map? Does the
static map meet these needs well?

Examples


Animation


EarthVisualizer


http://www.geovista.psu.edu/grants/VisEarth/climate3
2.html



Data exploration


CommonGIS


http://www.commongis.com/



Virtual reality


Digital LA


http://www.ust.ucla.edu/ustweb/projects.html

2. Map Animation



Dynamics


Examples of animations


Dealing with temporal data


Depicting the process of thunderstorm development
http://www.mediaport.net/CP/CyberScience/BDD/fich_050.en.html


Depicting ozone hole over time (Plate 20.1A)
http://www.research.ibm.com/people/l/lloydt/ozone_video.mpg


Depicting climate change over time (Color plate 20.2)


Depicting urban growth (Color plate 20.3)


Dealing with non
-
temporal data


Animating map design parameters with a view to
examining the effect of different choice (Figure 20.3,
Figure 20.5); “sequencing”


Animations for courseware and lectureware


Assists students in learning concepts

Categories of animation


Animations emphasizing
change


Change in space


Change in attribute



Animations emphasizing
location


Animation can assist in emphasizing location



Animations emphasizing
attribute


Animation can emphasize an attribute by highlighting
selected portions of it

Categories of animation


Animations emphasizing
change


Change in space


Change in position (zero
-
dimension)


e.g. mean center of U.S. population for each decennial
census


Change in shape, size, or extent of a phenomenon
(more than zero
-
dimension)


e.g. animated map of hurricane over time


Change in attribute


e.g. animated choropleth map of population over
time

Categories of animation


Animations emphasizing
location


Animation can assist in emphasizing location


e.g. Using flashing
-
point symbols to attract attention



Animations emphasizing
attribute


Animation can emphasize an attribute by highlighting
selected portions of it


e.g. choropleth symbols are presented in sequence rather
than the entire map is presented at once

3. Data Exploration



Role of Map Users

Exploratory Data Analysis


Consists of a collection of descriptive and
graphical statistical tools


Central tendency, dispersion


Histogram, box plot, scatter plot



Intended to discover patterns in data and
formulate hypotheses



Imposes as little prior structure as possible

Data exploration


Info. visualization

Map

Statistics


To illustrate the philosophy of data
exploration for maps, let’s see image
captures from CommonGIS (GIS software
for exploratory data analysis)

Interactive map symbolization in
CommonGIS

West
-
to
-
east
increase

Clusters of
low values
around
Porto and
Lisboa

One more
cluster of
low values

Coast
-
inland
contrast

Clusters of
high values in
central
-
east

By moving the slider, we see more patterns and gain more understanding of value distribution

Porto

Lisboa

Link between information
visualization techniques and maps


Map and scatter plot: the same technique

Map and dot plot; each district shown
on the map is also represented by a dot

Map

Dot
plot

A district pointed on the map with
the mouse is simultaneously
highlighted on the map and the plot

Using Cumulative Curves

Some statistics about the result:

In these areas over 7.82% people have
high school education. Here lives 33.1%
of the total country’s population.

In the most part of
Portugal (coloured in
blue) the proportion of
people having high
school education is below
4.67. However, on this
large territory only one
third of the country’s
population lives.

is simultaneously
highlighted here,

Focusing & multiple views

An object
pointed on
the map with
the mouse

and here,

and here,

but not here: this is an
aggregated view that does
not show individual objects

Focusing and Visual Comparison
on Other Map Types

Outlier

Maximum represented value

Value to compare with

Minimum value

Spatial Distribution of Events

The small circles represent the earthquakes
that occurred in Western Turkey and the
neighbourhood between 01.01.1976 and
30.12.1999

By applying the
temporal filter
, we can
investigate the spatial distribution on any
time interval

Here we see only the earthquakes
that occurred during 30 days from
15.05.1977 to 13.06.1977

Progress of Spatial Patterns
over Time

Map animation allows us to see how the spatial distribution of
events and their characteristics evolve over time

15.05.1977
-

13.06.1977

25.05.1977
-

23.06.1977

04.06.1977
-

03.07.1977

14.06.1977
-

13.07.1977

24.06.1977
-

23.07.1977

04.07.1977
-

02.08.1977

Each animation frame in this example covers 30
-
days time interval. The step between the
frames is 10 days. Hence, there is 20 days overlap between the adjacent frames.

Exploration of Behaviors

The value flow symbols show us
the evolution of attribute values
(behaviour) at each location.

Unfortunately, symbol overlapping
creates significant inconveniences,
and zooming does not always help

Data Transformations for
Behavior Exploration

As with time maps, various data transformations
can be applied to value flow maps.

Here we have applied the comparison to the mean: the values for each
moment are replaced by their differences to the country’s mean at the
same moment. Yellow colour corresponds to positive differences, and
blue


to negative. We have received a rather clear spatial pattern.

Methods of data exploration


Manipulating data


Varying the symbolization


Manipulating the user’s viewpoint (interactivity)


Highlighting portions of a data set (brushing)


Multiple view (linking)


Linking maps with other forms of display


Animation (dynamics)


Access to miscellaneous resources (multimedia)


Automatic map interpretation (i.e. data mining)

Read Slocum section 21.2

4. Virtual Environments



Immersion

Defining Virtual Reality (VR)


Virtual Reality in Action


Have you ever thought about ...?


‘I wish I could experience the environment
as if I were there without having to be
there’



Conventional 2D map does not offer a
‘real’ sense of being there

Learning Geography using VR


Virtual terrain


http://www.truflite.com/images/MonumentValley.mpg


Virtual cities


http://www.ust.ucla.edu/ustweb/Projects/PROJECTS/videos/FirstStreetW_exist.wmv

Google Earth


Let us consider different ways to
represent the Earth’s topography



Remotely sensed image


2D contour map (e.g. topographic map)


3D perspective map (e.g. block diagram)


Fly
-
through 3D perspective map


Representing urban environment…


Remotely sensed image


2D map


3D built form


Walk
-
through the urban environment

Virtual Environment (VE)


VE can be seen as the uppermost level in
a hierarchy that starts with the traditional
two
-
dimensional map

Static 2D

Static 2.5D

Dynamic/interacti
ve 2.5D/3D

The Virtual Environment defined


3
-
D computer
-
based simulation of a real or
imagined environment that users are able
to navigate through and interact with

Characterizing VE


Immersion


Offers realistic view of the phenomenon


High dimensionality


3D, and time


Dynamics


Movement of objects, temporal elements


High interactivity


User can control and manipulate objects


Feeding sensory input to the user


Utilize multiple human sensory perceptions

Discussion questions


How is VE different from cyberspace?



How is VE different from multimedia?



How is VE different from animated map?

Technologies for creating VE


The technology for creating VR can be
broken down into three parts:


Display


CRT display


Hardware controls


mouse and keyboard as controls


GUI


Microsoft Windows as the interface

Five basic forms of display
technologies


Viewed without special devices (e.g.
eyeglasses)


Desktop display


Wall
-
size display


Viewed with special devices


Head
-
mounted display (HMD)


Room
-
format (e.g. CAVE)


Table
-
format display (e.g. immersaDesk)

Viewed without special display


Desktop display: the most common
approach for depicting VR


Wall
-
size display: Covers a large portion of
a wall by tiling images created by multiple
projectors


Head
-
mounted display (HMD)


Helmet
-
like device placed on the user’s
head that shields the real world view and
provides images of the VR to each eye


Sophisticated HMD enables a
stereoscopic view

Room
-
format displays


Provides a room size view of VR by
projecting images onto three walls and the
floor (e.g. CAVE)

Table
-
format display


VR is projected onto a single screen that is
tilted at a 45 degree angle (e.g.
ImmersaDesk)

Applications of Geospatial VE


Virtual cities


Virtual field course


Digital earth

Virtual Cities: demo


Virtual Cities





Forms


Takes the form of highly detailed visual representation of
buildings (and related structures) within the city


Functions
(in the order of degree of development)


Property development project


most common


Assist citizens being involved in planning process


Assist researchers or citizens enhancing their understanding
urban process (simulation)


future development


Barriers


Lack of focus on urban process


Lack of available data


Listing of virtual cities


http://www.casa.ucl.ac.uk/3dcities/table_all.htm

Virtual Field Course: demo


http://www.geog.le.ac.uk/vfc/education/vipsSoftw
are.html



Users to explore the 3
-
D character of the natural
landscape where fieldwork is going to be
undertaken or has already been done (e.g.
traVelleR)



Users can plan routes for use with GPS
receivers and plot them on returning from the
field (e.g. panoraMap)

VR for education


VR help students understand phenomena that
cannot be directly experienced


VR increase students’ engagement in learning
tasks


VR enable rescaling objects and process in time
and space (e.g. a daily tidal cycle can be
compressed to five seconds)


VR allows students to make errors that might be
disastrous in the real world (e.g. experiments in
fighting forest fires)

Digital Earth: quote from Al Gore (1998)

-

Your children’s magic carpet ride
-


Imagine… a young children going to a Digital Earth exhibit at
a local museum. After donning a HMD, she sees Earth as it
appears from space. Using a data glove, she zooms in, using
higher and higher levels of resolution, to see continents, then
regions, countries, cities, and finally individual houses, trees,
and other natural and man
-
made objects. Having found an
area of the planet she is interested in exploring, she takes the
equivalent of a “magic carpet ride” through a 3
-
D visualization
of the terrain… Using the systems’ voice recognition
capabilities, she is able to request information on land cover,
distribution of plant and animal species, and so on… she is
not limited to moving through space, but can also travel
through time. After taking a virtual field
-
trip to Paris to visit the
Louvre, she moves backward in time to learn about French
history…

From
http://www.digitalearth.gov

Digital Earth


Vision of full
-
fledged digital representation
of multiresolution space, time, and
attribute (i.e. 4D)

Realizing the vision of Digital
Earth is underway

Google Earth is one realized
form of Digital Earth

5. Conclusions


What differentiates GeoViz from traditional
cartography?

Read Slocum section 1.5

Role of Maps

Map presentation vs. data exploration



Map presentation

(Traditional
cartography)

Data exploration

(Geovisualization)

Interaction between
map and user


Low

High

Public or private realm


Public

Private

Roles

Information sharing

Present known

Promote visual
communication

Knowledge construction

Reveal unknown

Facilitate visual thinking

The Geovisualization defined


Creation and use of visual representations
to facilitate thinking, understanding, and
knowledge construction about human and
physical environments, at geographic
scales of measurement

From MacEachren

What are advantages of geovisualization
compared to traditional cartographic product?


Query


You can make a simple geographic inquiry


See how message is sensitive to input data elements


Transformation


Data can be manipulated such that objectives can be served
better; it helps you overcome the limitation of traditional
cartographic products (e.g. choropleth map) such as


Cartogram: areal size adjusted to magnitudes


Dasymetric map: spatial overlay


Immersion


Expand the capacity to experience the world through virtual
environment (3D representation of the world)


Data
-
rich environment (LiDar), Computing power (animation)