Exploratory Analysis of
Spatial and Temporal Data
Natalia Andrienko · Gennady Andrienko
Exploratory Analysis
of Spatial and
Temporal Data
A Systematic Approach
With 245 Figures and 34 Tables
123
Authors
Natalia Andrienko
Gennady Andrienko
Fraunhofer Institute AIS
Schloss Birlinghoven
53754 Sankt Augustin, Germany
gennady.andrienko@ais.fraunhofer.de
http://www.ais.fraunhofer.de/and
Library of Congress Control Number: 2005936053
ACM Computing Classification (1998): J.2, H.3
ISBN-10 3-540-25994-5 Springer Berlin Heidelberg New York
ISBN-13 978-3-540-25994-7 Springer Berlin Heidelberg New York
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Preface
This book is based upon the extensive practical experience of the authors 
in  designing  and  developing  software  tools  for  visualisation  of  spatially 
referenced  data  and  applying  them  in  various  problem  domains.  These 
tools  include  methods  for  cartographic  visualisation;  non-spatial  graphs; 
devices  for  querying,  search,  and  classification;  and  computer-enhanced 
visual techniques. A common feature of all the tools is their high user in-
teractivity,  which  is  essential  for  exploratory  data  analysis.  The  tools  can 
be used conveniently in various combinations; their cooperative function-
ing is enabled by manifold coordination mechanisms. 
Typically,  our  ideas  for  new  tools  or  extensions  of  existing  ones  have 
arisen  from  contemplating  particular  datasets  from  various  domains.  Un-
derstanding  the  properties  of  the  data  and  the  relationships  between  the 
components of the data triggered a vision of the appropriate ways of visu-
alising  and  exploring  the  data.  This  resulted  in  many  original  techniques, 
which were, however, designed and implemented so as to be applicable not 
only to the particular dataset that had incited their development but also to 
other  datasets  with  similar  characteristics.  For  this  purpose,  we  strove  to 
think  about  the  given  data  in  terms  of  the  generic  characteristics  of  some 
broad class that the data belonged to rather than stick to their specifics.  
From  many  practical  cases  of  moving  from  data  to  visualisation,  we 
gained a certain understanding of what characteristics of data are relevant 
for  choosing  proper  visualisation  techniques.  We  learned  also  that  an  es-
sential stage on the way from data to the selection or design of proper ex-
ploratory tools is to envision the questions an analyst might seek to answer 
in  exploring  this  kind  of  data,  or,  in  other  words,  the  data  analysis  tasks. 
Knowing  the  questions  (or,  rather,  types  of  questions),  one  may  look  at 
familiar techniques from the perspective of whether they could help one to 
find answers to those questions. It may happen in some cases that there is a 
subset of existing tools that covers all potential question types. It may also 
happen that for some tasks there are no appropriate tools. In that case, the 
nature  of  the tasks  gives  a  clue  as  to  what  kind of  tool  would  be helpful. 
This is an important initial step in designing a new tool. 
Having  passed  along  the  way  from  data  through  tasks  to  tools  many 
times, we found it appropriate to share the knowledge that we gained from 
VI     Preface 
this  process  with  other  people.  We  would  like  to  describe  what  compo-
nents  may  exist  in  spatially  referenced  data,  how  these  components  may 
relate  to  each  other,  and  what  effect  various  properties  of  these  compo-
nents  and  relationships  between  them  may  have  on  tool  selection.  We 
would  also  like  to  show  how  to  translate  the  characteristics  of  data  and 
structures into potential analysis tasks, and enumerate the widely accepted 
principles and our own heuristics that usually help us in proceeding from 
the tasks to the appropriate approaches to accomplishing them, and to the 
tools that could support this. In other words, we propose a methodological 
framework for the design, selection, and application of visualisation tech-
niques and tools for exploratory analysis of spatially referenced data. Par-
ticular attention is paid to spatio-temporal data, i.e. data having both spa-
tial and temporal components. 
We  expect  this  book  to  be  useful  to  several  groups  of  readers.  People 
practising analysis of spatially referenced data should be interested in be-
coming familiar with the proposed illustrated catalogue of the state-of-the-
art  exploratory  tools.  The  framework  for  selecting  appropriate  analysis 
tools might also be useful to them. Students (undergraduate and postgradu-
ate) in various geography-related disciplines could gain valuable informa-
tion about the possible types of spatial data, their components, and the re-
lationships between them, as well as the impact of the characteristics of the 
data on the selection of appropriate visualisation methods. Students could 
also  learn  about  various  methods  of  data  exploration  using  visual,  highly 
interactive  tools,  and  acknowledge  the  value  of  a  conscious,  systematic 
approach to exploratory data analysis. The book may be interesting to re-
searchers in computer cartography, especially those imbued with the ideas 
of  cartographic  visualisation,  in  particular,  the  ideas  widely  disseminated 
by  the  special  Commission  on  Visualisation  of  the  International  Carto-
graphic Association. Our tools are in full accord with these ideas, and our 
data-  and  task-analytic  approach  to  tool  design  offers  a  way  of  putting 
these ideas into practice. It can also be expected that the book will be in-
teresting to researchers and practitioners dealing with any kind of visuali-
sation, not necessarily the visualisation of spatial data. Many of the ideas 
and  approaches  presented  are  not  restricted  to  only  spatially  referenced 
data, but have a more general applicability. 
The  topic  of  the  book  is  much  more  general  than  the  consideration  of 
any particular software: we investigate the relations between the character-
istics  of  data,  exploratory  tasks  (questions),  and  data  exploration  tech-
niques. We do this first on a theoretical level and then using practical ex-
amples.  In  the  examples,  we  may  use  particular  implementations  of  the 
techniques, either our own implementations or freely available demonstra-
tors.  However,  the  main  purpose  is  not  to  instruct  readers  in  how  to  use 
Preface      VII 
this or that particular tool but to allow them to better understand the ideas 
of exploratory data analysis. 
The book is intended for a broad reader community and does not require 
a  solid  background  in  mathematics,  statistics,  geography,  or  informatics, 
but only a general familiarity with these subjects. However, we hope that 
the  book  will  be  interesting  and  useful  also  to  those  who  do  have  a  solid 
background in any or all of these disciplines. 
Acknowledgements 
This  book  is  a  result  of  a  theoretical  generalisation  of  our  research  over 
more than 15 years. During this period, many people helped us to establish 
ourselves and grow as scientists. We would like to express our gratitude to 
our  scientific  “parents”  Nadezhda  Chemeris,  Yuri  Pechersky,  and  Sergey 
Soloview, without whom our research careers would not have started. We 
are  also  grateful  to  our  colleagues  and  partners  who  significantly  influ-
enced and encouraged our work from its early stages, namely Leonid Mi-
kulich, Alexander Komarov, Valeri Gitis, Maria Palenova, and Hans Voss.  
Since  1997  we  have  been  working  at  GMD,  the  German  National  Re-
search  Centre  for  Information  Technology,  which  was  later  transformed 
into the AIS (Autonomous Intelligent Systems) Fraunhofer Institute. Insti-
tute directors Thomas Christaller and Stefan Wrobel and department heads 
Hans  Voss  and  Michael  May  always  supported  and  approved  our  work. 
All our colleagues were always cooperative and helpful. We are especially 
grateful to Dietrich Wettschereck, Alexandr Savinov, Peter Gatalsky, Ivan 
Denisovich,  Mark  Ostrovsky,  Simon  Scheider,  Vera  Hernandez,  Andrey 
Martynkin, and Willi Kloesgen for fruitful discussions and cooperation. 
Our research was developed in the framework of numerous international 
projects.  We  acknowledge  funding  from  the  European  Commission  and 
the friendly support of all our partners. We owe much to Robert Peckham, 
Jackie  Carter,  Jim  Petch,  Oleg  Chertov,  Andreas  Schuck,  Risto  Paivinen, 
Frits  Mohren,  Mauro  Salvemini,  and  Matteo  Villa.  Our  work  was  also 
greatly  inspired  by  a  fruitful  (although  informal)  cooperation  with  Piotr 
Jankowski and Alexander Lotov. 
Our participation in the ICA commissions on Visualisation and Virtual 
Environments,  Maps  and  the  Internet,  and  Theoretical  Cartography  had  a 
strong influence on the formation and refinement of our ideas. Among all 
the  members  of  these  commissions,  we  are  especially  grateful  to  Alan 
MacEachren, Menno-Jan Kraak, Sara Fabrikant, Jason Dykes, David Fair-
bain, Terry Slocum, Mark Gahegan, Jürgen Döllner, Monica Wachowicz, 
VIII     Preface 
Corne van Elzakker, Michael Peterson, Georg Gartner, Alexander Volod-
tschenko, and Hans Schlichtmann.  
Discussions  with  Ben  Shneiderman,  Antony  Unwin,  Robert  Haining, 
Werner  Kuhn,  Jonathan  Roberts,  and Alfred  Inselberg  were  a  rich  source 
of  inspiration  and  provided  apt  occasions  to  verify  our  ideas.  Special 
thanks  are  due  to  the  scientists  whose  books  were  formative  for  our  re-
search, namely John Tukey, Jacques Bertin, George Klir, and Rudolf Arn-
heim. 
The  authors  gratefully  acknowledge  the  encouraging  comments  of  the 
reviewers,  the  painstaking  work  of  the  copyeditor,  and  the  friendly  coop-
eration of Ralf Gerstner and other people of Springer-Verlag. 
We  thank  our  family  for  the  patience  during  the  time  that  we  used  for 
discussing and writing the book in the evenings, weekends, and during va-
cations.
Almost  all  of  the  illustrations  in  the  book  were  produced  using  the 
CommonGIS system and some other research prototypes developed in our 
institute. Online demonstrators of these systems are available on our Web 
site  http://www.ais.fraunhofer.de/and  and  on  the  web  site  of  our  institute 
department  http://www.ais.fraunhofer.de/SPADE.  People  interested  in  us-
should 
ing 
of  CommonGIS, 
http://www.CommonGIS.com.  
software 
site 
the 
visit 
the 
The datasets used in the book were provided by our partners in various 
projects.
1. Portuguese  census.  The  data  set  was  provided  by  CNIG  (Portuguese 
National Centre for Geographic Information) within the EU-funded pro-
ject  CommonGIS  (Esprit  project  28983).  The  data  were  prepared  by 
Joana Abreu, Fatima Bernardo, and Joana Hipolito.
2. Forests  in  Europe.  The  dataset  was  created  within  the  project  “Com-
bining  Geographically  Referenced  Earth  Observation  Data  and  Forest 
Statistics for Deriving a Forest Map for Europe” (15237-1999-08 F1ED 
ISP FI). The data were provided to us by EFI (the European Forest Insti-
tute within the project EFIS (European Forest Information System), con-
tract number: 17186-2000-12 F1ED ISP FI. 
3. Earthquakes  in  Turkey.  The  dataset  was  provided  within  the  project 
SPIN!  (Spatial  Mining  for  Data  of  Public  Interest)  (IST  Programme, 
project IST-1999-10536) by Valery Gitis and his colleagues. 
4. Migration of white storks. The data were provided by the German Re-
search Centre for Ornithology of the Max Planck Society within a Ger-
man school project called “Naturdetektive”. The data were prepared by 
Peter Gatalsky.