GEOBIA state of the art, science or technology

Transcription

1 GEOBIA state of the art, science or technology Paul Aplin School of Geography,

2 Geographic Object-Based Image Analysis Aplin et al., 1999, Remote Sensing of Environment

3 Progress? Contemporary GEOBIA Commercial software Accessible/available tools Quick/easy analysis Processing time: ~10 minutes

4 Thesis GEOBIA has experienced dramatic technological advancement over the last decade Accessible/available tools Quick/easy analysis Myriad applications, users Is this all good!? Where is GEOBIA now? Is it a science or a technology (and does this matter)? Does it have a future?

5 GEOBIA state of the art, science or technology RELIGION

6 Preaching to the converted

7 GEOBIA state of the art, science or technology HISTORY

8 GEOBIA foundations GEOBIA is not a recent invention Early experiments in the 1980s and even late 1970s Lobo, 1997, IEEE TGRS Molenaar and Janssen, 1992

9 No. citations Recent growth Explosion of interest in GEOBIA Growth in literature Consolidation of discipline GEOBIA develops an identity Bibliographic citations by topic (Web of Science) GEOBIA OBIA Year

10 Causes of growth part 1 Inherent value of GEOBIA Mapping accuracy often higher than pixel-based approaches Desirable representation of world often more understandable/usable than raster grid Pixel-based classification Object-based classification

11 GEOBIA state of the art, science or technology TECHNOLOGY

12 No. citations Causes of growth part 2 Commercial software availability? Bibliographic citations by topic (Web of Science) Year GEOBIA OBIA ecognition Definiens

13 Software availability Great for users! Good for the discipline?

14 Black box GEOBIA mechanics often hidden from user Tendency towards button-pushing Ill-informed/under-educated user community Uncritical/trusting use of available tools Potentially constrains scope/ambition of GEOBIA users Input Magic! Output

15 Parochial systems Commercial software packages seem highly parochial Bespoke language and definitions (jargon) Workflows involve specific analytical steps Lack of standards and interoperability Potentially constrains broader understanding of GEOBIA concepts and consolidation of the discipline segmentation context solidity circularity roundness shape scale parameter texture scale factor smoothness compactness scale level asymmetry

16 No. citations End product A quick survey of GEOBIA literature: 'GEOBIA' citations by category Theory Method Application Year Dominated by simple application and minor methodological adjustment Evidence that GEOBIA is technology-led? Is this a threat to the discipline?

17 GEOBIA state of the art, science or technology GEOGRAPHY

18 What is geography? Geography is the study of Earth s landscapes, peoples, places and environments. It is, quite simply, about the world in which we live. Geography has been called the world discipline and the bridge between the human and the physical science. Geography (from Greek γεωγραφία, geographia) a literal translation would be to describe or write about the Earth. The first person to use the word geography was Eratosthenes ( BC).

19 The First Law of Geography Everything is related to everything else, but near things are more related to each other Tobler, 1970 Variogram Proposed towards the end of the 1960s quantitative revolution Not wholly intended as a serious proposition the first law title was suggested almost as a joke Initially ignored by Geography, as the discipline retreated from positivism (quantitative science) in the 1970s The First Law has gained prominence more recently through the growth of GIS

20 The First Law and GEOBIA Does GEOBIA fulfil the First Law of Geography? Consider how object size varies Are rasters more appropriate? Spatial support/resolution plays a significant role Variogram

21 GEOBIA state of the art, science or technology Geographic Information Science

22 GISystems Early GIS was technology-led Good for users? Bad for the discipline?

23 Object-orientation Object-orientation is a longstanding theme within GIS Generally focuses on vector data model instead of raster Links to debates around raster/vector integration and conversion Much early GEOBIA conducted in this context Technological constraints existed since true raster/vector integration was unachievable

24 GIScience Geographical Information Science Goodchild, 1992 First formal attempt to set a theoretical/scientific agenda for GIS University Consortium for Geographic Information Science emerged in 1995 International Journal of Geographical Information Science (GIS) formed in 1997 (formerly IJGISystems) Benchmark GIScience Research Agenda published in 2005 Major revision underway

25 The Second Law and GEOBIA Recently a second law of geography has been proposed around spatial heterogeneity This relates to non-stationarity and involves methods such as geographically weighted regression How does GEOBIA conform to this law?

26 GEOBIA state of the art, science or technology SCIENCE

27 No. citations GEOBIA as a discipline Can GEOBIA follow the GIS model and shift from system to science? Another glance at the literature: 'GEOBIA' citations by category Theory Method Application Year Some (growing?) evidence of theoretical engagement Academic leaders promoting this new paradigm

28 Scale of observation GEOBIA can contribute to our fundamental understanding of space (not just map it) E.g. Pixels: the forgotten objects of GEOBIA (Smith 2014) Complex habitat monitoring in Wicken Fen, UK Seeks to rehabilitate the pixel and exploit this as part of GEOBIA output (not just as a static input)

29 Spatial accuracy GEOBIA can engage with fundamental theories related to accuracy, quality and truth E.g. Integrating user information into image segmentation assessment (Costa 2014) Questions the current reliance on geometric assessment to identify correct segmentation One size does not fit all!

30 Open source development Open source GEOBIA tools growing in popularity Not only targeted packages, but also general programming environments OBIA was a problem only because of the difficulty of commercial GIS and RS software in dealing with rasters and vectors. I have never encountered this is an issue in R. I do OBIA all the time often without even realising that I am doing it. Comber, 2014, pers comm Open source software enables a transparent and dynamic research environment RHSEG rtwobia Brunsdon and Comber, 2014, An Introduction to R for Mapping and Spatial Analysis, SAGE.

31 Expanding the community The core GEOBIA community seems quite compact Scope for broader engagement with cognate subjects Perhaps especially the traditional GIS/ vector community

32 GEOBIA state of the art, science or technology ART

33 Eruption (remotesensingart.com)

34 What s wrong with pixels? Inherent value of GEOBIA desirable representation of world? Are objects really more pleasing and understandable than pixels? GEOBIA is a form of abstraction or simplification This isn t always pretty!

35 Cartography GEOBIA has links to traditional cartographic debates about map generalization More recently psychological debates about perceptions of space

36 GEOBIA state of the art, science or technology PHILOSOPHY

37 Conclusion Preaching with the converted? Didn t plan for such success with GEOBIA Not solved all the problems More research is needed GEOBIA shouldn t be restricted to images; include DEMs... We need new methodologies We need hypothesis-driven serious research Blaschke, GEOBIA 2014 Round-table Singing from the same hymn sheet!

38 The early foundations of remote sensing? Man must rise above the Earth, to the top of the atmosphere and beyond, for only thus will he fully understand the world in which he lives Socrates circa 399BC Ευχαριστώ