Nome e/ou Título e/ou Outros25-06-2013 1
Flickr geotagged and publicly available photos:
preliminary study of its adequacy...
Agenda
• Introduction
• Objective
• Related work:
– Volunteered Geographic Information
– Land Use/Cover mapping
– VGI and ...
Introduction
• Land Use/Cover (LULC) mapping plays a very important role in a
vast number of research fields
• Produced ba...
Objective
• Preliminary analysis of the adequacy of photos from the
Flickr initiative in order to use them as a source of ...
Background (1)
• Volunteered Geographic Information
– Geographic Information (GI) has been produced by mapping
agencies an...
Background (2)
• Volunteered Geographic Information
– Several terminologies arise always related with a type of User
Gener...
Background (3)
• Volunteered Geographic Information
– The participation and contribution of citizens in this filed is not
...
Background (4)
• Land Use/Cover mapping
– According to Cihlar (2000) LULC mapping consists of four main
steps: data acquis...
Background (5)
• VGI and Land Cover mapping
– Geo-Wiki.Org is one project described as a global network of
volunteers who ...
Study area and Datasets (1)
• Study area
– The study area is Continental Portugal
– The land cover is mainly composed by a...
Study area and Datasets (2)
25-06-2013 11
a)
c)
b
)
Fig. 1. Datasets used: a) CAOP database, b) Flickr photos’ locations, ...
Study area and Datasets (3)
25-06-2013 12
a)
c)
b
)
Level 1 Area (Km2
) Level 2 Area (Km2
)
1 Artificial surfaces 3088.01
...
Methods
• Analysis of the temporal distribution of Flickr photos
• Analysis of the spatial distribution by confronting the...
Results (1)
• Temporal distribution of the Flickr photos
25-06-2013 14
Fig. 2. Number of Flickr photos per year (a); month...
Results (2)
25-06-2013 15
Fig. 3. Flickr photos
frequency distribution by
municipalities: absolute
number of photos (a)
an...
Results (3)
25-06-2013 16
Fig. 4. Spatial distribution of Flickr photos over
the municipalities of Lisboa (a), Pedrógão
Gr...
Results (4)
• Distribution of Flickr photo locations over CLC classes
25-06-2013 17
Level 1 classes Area (Km2
) Num. photo...
Results (5)
• Distribution of Flickr photo locations over CLC classes
25-06-2013 18
CLC Level 2 classes Frequency Percenta...
Results (6)
• Cross analysis
25-06-2013 19
Fig. 5. Monthly
distribution of
photos in each CLC
level 1 class.
GEOG-AND-MOD ...
Results (7)
• Cross analysis
25-06-2013 20
Fig. 6. Monthly
variation of photos
by district.
GEOG-AND-MOD 13 • ICCSA 2013
J...
Results (8)
25-06-2013 21
District
Min Max
Ratio
Month Value Month Value
Aveiro May 439 Oct 1748 3.98
Beja Feb 140 Jul 160...
Conclusions
• Large number of georeferenced photos available
• Spatial asymmetry and irregular distribution of the data
wa...
Future work
• Study and analysis of other VGI sources
• Extend the study area to Europe in order to characterize
a broader...
Acknowledgements
This research has been partially supported by COST Action
TD1202, Mapping and the Citizen Sensor.
25-06-2...
Nome e/ou Título e/ou Outros25-06-2013 25
Thank you for your attention
cảm ơn bạn đã quan tâm của bạn
Jacinto Estima and M...
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Flickr Geotagged and Publicly Available Photos: Preliminary Study of Its Adequacy for Helping Quality Control of Corine Land Cover

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  • - research fields: LULC monitoring and modeling, monitoring of tropical deforestation, climate changes, among many others
  • LC attempts to characterize the biophysical features while LU is more related with the human interaction with these natural features AA its important in order to provide the cartography with a degree of confidence to those who wants to use it
  • Flickr Geotagged and Publicly Available Photos: Preliminary Study of Its Adequacy for Helping Quality Control of Corine Land Cover

    1. 1. Nome e/ou Título e/ou Outros25-06-2013 1 Flickr geotagged and publicly available photos: preliminary study of its adequacy for helping quality control of Corine Land Cover Jacinto Estima and Marco Painho Jacinto.estima@gmail.com; painho@isegi.unl.pt www.isegi.unl.pt Eighth International Conference on "Geographical Analysis, Urban Modeling, Spatial Statistics“ GEOG-AND-MOD 13 2013 International Conference on Computational Science and its Applications (ICCSA 2013) June 24th - June 27th , 2013 - International University, Ho Chi Minh City, Vietnam
    2. 2. Agenda • Introduction • Objective • Related work: – Volunteered Geographic Information – Land Use/Cover mapping – VGI and Land Cover mapping • Material and Methods • Results and Discussion • Conclusions and Future Work 25-06-2013 2 GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    3. 3. Introduction • Land Use/Cover (LULC) mapping plays a very important role in a vast number of research fields • Produced based on interpretation and classification of remote sensing data, made by highly skilled people • “Ground truth” information is required in some phases • Since 2005 the spatial data produced by volunteers became exponentially available over the Web - great opportunity • Some challenges related with its heterogeneity, quality control and metadata absence, etc. 25-06-2013 3 GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    4. 4. Objective • Preliminary analysis of the adequacy of photos from the Flickr initiative in order to use them as a source of field data in the quality control of the LULC databases: – Analyze this source in terms of its temporal and spatial distribution and also its distribution over the different LULC classes 25-06-2013 4 GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    5. 5. Background (1) • Volunteered Geographic Information – Geographic Information (GI) has been produced by mapping agencies and corporations – This approach is very expensive favoring the most important and unchanging geographic themes – Google Maps was a revolution – Cheaper positioning devices combined with camera and mobile or smart phones, fine resolution-imagery, broad band communications, are empowering citizens to produce and share their own maps 25-06-2013 5 GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    6. 6. Background (2) • Volunteered Geographic Information – Several terminologies arise always related with a type of User Generated Content (UGC) that deals with spatial content • Neogeography (Tuner, 2006) • Volunteered Geographic Information (Goodchild, 2007) • Crowdsourcing Geospatial (Hudson-Smith, Batty, Crooks, & Milton, 2009) – The specialist meeting held in Santa Barbara, CA in December 2007, organized by the National Center for Geographic Information and Analysis (NCGIA) proved the importance of this type of data 25-06-2013 6 GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    7. 7. Background (3) • Volunteered Geographic Information – The participation and contribution of citizens in this filed is not new: • 1930s when teachers and school children contributed to land use surveys of Britain • urban residents involved in the Bunge's “Geographical Expeditions” in 1971 • ‘‘Did you feel it?’’ - portal established by the USGS Earthquake Hazards Program for earthquake mapping (1999) – Elwood et al. (2011) counted ninety-nine VGI initiatives, 70% of them started after 2005 – 2005 can be considered a turn point 25-06-2013 7 GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    8. 8. Background (4) • Land Use/Cover mapping – According to Cihlar (2000) LULC mapping consists of four main steps: data acquisition, pre-processing, analysis/classification, and product generation and documentation – The analysis/classification phase must end with the Accuracy Assessment (AA) – AA is made by confronting the produced cartography with reference information assumed as true – Very important task to offer map quality indicators – Field work is needed (increases the cost and the time) 25-06-2013 8 GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    9. 9. Background (5) • VGI and Land Cover mapping – Geo-Wiki.Org is one project described as a global network of volunteers who wish to help improving the quality of global land cover maps – Virtual Interpretation of Earth Web-Interface Tool (VIEW-IT) for Collecting Land-Use/Land-Cover (LULC) Reference Data is another initiative still as “a proof of concept” – More recently, in 2010, Leung and Newsam conducted some experiments to derive maps of “what-is-where” from large collections of georeferenced photos in an automated way 25-06-2013 9 GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    10. 10. Study area and Datasets (1) • Study area – The study area is Continental Portugal – The land cover is mainly composed by agricultural and forest areas (around 95%) • Datasets (Fig. 1) – Geo-referenced and publicly available Flickr photos’ locations • Downloaded 414,323 and used 409,829 after pre-processing • study period ranging between 2004 and 2012 – Corine Land Cover (CLC) database for the CLC2006 inventory - version 16 (04/2012) – raster format – Portuguese official administrative boundaries database - “Carta Administrativa Oficial de Portugal” (CAOP) – vector format 25-06-2013 10 GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    11. 11. Study area and Datasets (2) 25-06-2013 11 a) c) b ) Fig. 1. Datasets used: a) CAOP database, b) Flickr photos’ locations, c) CLC database. a) b) c) GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    12. 12. Study area and Datasets (3) 25-06-2013 12 a) c) b ) Level 1 Area (Km2 ) Level 2 Area (Km2 ) 1 Artificial surfaces 3088.01 11 Urban fabric 2274.38 12 Industrial, commercial and transport units 472.44 13 Mine, dump and construction sites 210.25 14 Artificial, non-agricultural vegetated areas 130.94 2 Agricultural areas 41996.50 21 Arable land 12444.56 22 Permanent crops 5938.69 23 Pastures 418.06 24 Heterogeneous agricultural areas 23195.19 3 Forest and semi natural areas 42620.95 31 Forests 20171.63 32 Scrub or herbaceous vegetation 20776.13 33 Open spaces with little or no vegetation 1673.19 4 Wetlands 1012.31 41 Inland wetlands 258.06 42 Maritime wetlands 754.25 5 Water bodies 361.75 51 Inland waters 351.06 52 Marine waters 10.69 Table 2. CLC nomenclature for level’s 1 and 2 (source: http://www.igeo.pt/gdr/pdf/CLC2006_nomenclature_addendum.pdf) GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    13. 13. Methods • Analysis of the temporal distribution of Flickr photos • Analysis of the spatial distribution by confronting the photos with the Portuguese municipalities • Analysis of the distribution over the different CLC classes • Cross analysis to compare the distribution of photos over CLC classes along with the spatial and temporal distributions 25-06-2013 13 GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    14. 14. Results (1) • Temporal distribution of the Flickr photos 25-06-2013 14 Fig. 2. Number of Flickr photos per year (a); monthly average of Flickr photos between 2004 and 2012 (b). a) b) GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    15. 15. Results (2) 25-06-2013 15 Fig. 3. Flickr photos frequency distribution by municipalities: absolute number of photos (a) and normalized by area (b). a) b) Spatial distribution of Flickr photo locations GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    16. 16. Results (3) 25-06-2013 16 Fig. 4. Spatial distribution of Flickr photos over the municipalities of Lisboa (a), Pedrógão Grande (b) and Vimioso (c). Spatial distribution of Flickr photo locations a) b) c) c) b) a) GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    17. 17. Results (4) • Distribution of Flickr photo locations over CLC classes 25-06-2013 17 Level 1 classes Area (Km2 ) Num. photos Perc. Density (photos/Km2 ) 1 Artificial surfaces 3088.01 322032 78.58% 104.28 2 Agricultural areas 41996.50 34270 8.36% 0.82 3 Forest and semi natural areas 42620.95 37129 9.06% 0.87 4 Wetlands 1012.31 2902 0.71% 2.87 5 Water bodies 361.75 13496 3.29% 37.31 GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    18. 18. Results (5) • Distribution of Flickr photo locations over CLC classes 25-06-2013 18 CLC Level 2 classes Frequency Percentage 11 Urban fabric 248866 60.72% 12 Industrial, commercial and transport units 34283 8.37% 13 Mine, dump and construction sites 408 0.10% 14 Artificial, non-agricultural vegetated areas 38475 9.39% 21 Arable land 5373 1.31% 22 Permanent crops 5094 1.24% 23 Pastures 426 0.10% 24 Heterogeneous agricultural areas 23377 5.70% 31 Forests 16709 4.08% 32 Scrub and/or herbaceous vegetation associations 12756 3.11% 33 Open spaces with little or no vegetation 7664 1.87% 41 Inland wetlands 37 0.01% 42 Maritime wetlands 2865 0.70% 51 Inland waters 6636 1.62% 52 Marine waters 6860 1.67% GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    19. 19. Results (6) • Cross analysis 25-06-2013 19 Fig. 5. Monthly distribution of photos in each CLC level 1 class. GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    20. 20. Results (7) • Cross analysis 25-06-2013 20 Fig. 6. Monthly variation of photos by district. GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    21. 21. Results (8) 25-06-2013 21 District Min Max Ratio Month Value Month Value Aveiro May 439 Oct 1748 3.98 Beja Feb 140 Jul 1607 11.48 Braga Jan 832 Aug 2382 2.86 Bragança Jan 18 Jul 471 26.17 Castelo Branco Mar 119 Aug 806 6.77 Coimbra Nov 569 Aug 1542 2.71 Evora Jan 328 Sep 897 2.73 Faro Dec 1118 Jul 4669 4.18 Guarda Jun 109 Aug 808 7.41 Leiria Feb 536 Aug 2340 4.37 Lisboa Jan 11018 Sep 21630 1.96 Portalegre Feb 137 Aug 491 3.58 Porto Jan 3247 Sep 7560 2.33 Santarem Feb 197 Sep 1007 5.11 Setubal Feb 1239 Sep 2573 2.08 Viana do Castelo Feb 221 Aug 1413 6.39 Vila Real Jan 154 Aug 596 3.87 Viseu Nov 173 Aug 798 4.61 Cross analysis GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    22. 22. Conclusions • Large number of georeferenced photos available • Spatial asymmetry and irregular distribution of the data was confirmed • Irregular distribution over different CLC classes • Temporal distribution is the most positive characteristic • This resource cannot be used alone for the purpose of helping the AA phase of LULC production • Some potential has been demonstrated and we truly believe that the solution could be to combine different sources of VGI 25-06-2013 22 GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    23. 23. Future work • Study and analysis of other VGI sources • Extend the study area to Europe in order to characterize a broader area and verify differences between countries. • Characterization of the content of title and other descriptive tags • A data model able to integrate all the suitable VGI should be further investigated and developed. 25-06-2013 23 GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    24. 24. Acknowledgements This research has been partially supported by COST Action TD1202, Mapping and the Citizen Sensor. 25-06-2013 24 GEOG-AND-MOD 13 • ICCSA 2013 June 25th - June 27th, 2013 - International University, Ho Chi Minh City, Vietnam
    25. 25. Nome e/ou Título e/ou Outros25-06-2013 25 Thank you for your attention cảm ơn bạn đã quan tâm của bạn Jacinto Estima and Marco Painho Jacinto.estima@gmail.com; painho@isegi.unl.pt www.isegi.unl.pt Eighth International Conference on "Geographical Analysis, Urban Modeling, Spatial Statistics“ GEOG-AND-MOD 13 2013 International Conference on Computational Science and its Applications (ICCSA 2013) June 24th - June 27th , 2013 - International University, Ho Chi Minh City, Vietnam

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