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20220824FOSS4G2022

 20220824FOSS4G2022

Analysis of the spatiotemporal accumulation process of Mapillary data and its relationship with OSM road data: A case study in Japan
https://talks.osgeo.org/foss4g-2022-academic-track/talk/9KGNRA/

Toshikazu SETO

August 24, 2022
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  1. 2022/08/24 FOSS4G 2022 Academic Track 1
    Analysis of the spatiotemporal accumulation process of
    Mapillary data and its relationship with OSM road data:
    A case study in Japan
    Toshikazu Seto* Ph.D. (tosseto)
    and Yuichiro Nishimura
    *: Associate Professor Department of Geography, Komazawa University
    OSGeo.JP (OSGeo Charter member) /OSMFJapan
    DOI: 10.5194/isprs-archives-XLVIII-4-W1-2022-403-2022
    A02
    KOMAZAWA UNIVERSITY
    Visual Identity Guidelines
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  2. 2022/08/24 FOSS4G 2022 Academic Track 2
    Overview of Mapillary Data in Japan
    Property Description Type Range of value
    key Keycode String 41,765,634
    ca Cardinal points Real 0 – 360 degrees
    camera_make Device maker String 91 types
    camera_model Device name String 488 types
    captured_at Timestamp Date
    from 2014-01-01
    to 2020-09-31
    pano
    Panoramic
    shooting
    Boolean
    Yes: 5,413,030
    No: 36,352,604
    sequence_key Sequence code String 41,765,634
    user_key Account code String 1,513
    username Account name String 1,513 users
    Mapillary API (v. 3, 2017)

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  3. 2022/08/24 FOSS4G 2022 Academic Track 3
    Database Construction
    1. Get data from Mapillary Search Image API (v. 3, 2017)
    ▶ GeoJSON(Zoom7 – total: 14h15m10s)
    2. Convert to GeoJSON ▶ PostGIS ▶FlatGeobuf (.fgb)
    • PostGIS: 1.79-GB ▶ .fgb: 11.73-GB with 41,765,634 records
    • Reading & processing .fgb was three times faster than local PostGIS
    3. Spatial Join with OSM road data attribution via QGIS
    • All OSM road data (.fgb): 3.2-GB with 8,313,281 records
    • the maximum search radius was set to 50 m of centerline
    4. Output 17.6-GB point database in .fgb (with 23 attribution)
    + Aggregate with polygon for each municipality
    (232.2 MB; 1903 records with 32 attribution)
    + Aggregate with 1-km Grids
    (126.5 MB; 388,762 records with 20 attribution)
    • https://github.com/tossetolab/mapillary-analysis-japan

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  4. 2022/08/24 FOSS4G 2022 Academic Track 4
    • 1500 unique Mapillary contributors
    during the six years, with the top 10
    users contributing approximately 90% of
    the images in Japan.
    • The proportion of Mapillary data
    compared to OSM road data has
    reached about 16% in some areas.
    • Approximately 40% of Mapillary related
    OSM roads have been updated since
    the Mapillary images were taken, which
    can help update OSM road data in Japan.
    Number of Mapillary
    postings per contributor
    OSM roads-Mapillary
    coverage rates
    Monthly Mapillary
    photos taken and
    number of contributed
    users.

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  5. 2022/08/24 FOSS4G 2022 Academic Track 5
    Last update date of OpenStreetMap road before
    and after Mapillary image taken by 1-km grid
    (unit: days)

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