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Mapping the world beyond web mercator

Mapping the world beyond web mercator

Most popular mapping presentations today, ranging from clients to servers, show and discuss only maps in EPSG:3857, the popular Mercator derived projection used by OSM as well as
most commercial tiles providers.

There is however an interesting, exciting world of map projections out there, that are still being used in a variety of context. This presentation will introduce the advancement made in GeoTools and GeoServer to handle those use cases, where users have a worldwide data set, and need to view all or part of it in multiple projections, some of which valid in a limited area, and requiring the software to perform a proper display of it on the fly, without any preparation.

We’ll discuss GeoTools/GeoServer “advanced projection handling” manages to deal with these cases, wrapping data, dealing with the poles and the dateline, cutting on the fly excess data, densifying on the fly long lines as needed to ensure a smooth reprojection, for a variety of cases, ranging from seemingly innocuous datum shifts, maps having the prime meridian over the pacific, and the various tricks to properly handle stereographic, transverse mercator, Lambert conic and other limited area projections against world wide source data sets.

Simone Giannecchini
PRO

September 02, 2018
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  1. Mapping beyond
    web mercator
    Ing. Andrea Aime
    GeoSolutions

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  2. GeoSolutions

    Italian SME

    Expertise
    • Image Processing, GeoSpatial Data Fusion
    • Java, Java Enterprise, C++, Python
    • JPEG2000, JPIP, Advanced 2D visualization

    Supporting/Developing FOSS4G projects

    GeoServer, MapStore

    GeoNetwork, GeoNode, Ckan

    Clients

    Public Agencies

    Private Companies

    http://www.geo-solutions.it
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  3. Why Web Mercator

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  4. Why: it’s everywhere, it’s free
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  5. Why: familiar
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  6. Why: easy
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  7. Why: fair to the dateline
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  8. Some reasons to avoid Web Mercator

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  9. One reason to rule them all
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  10. Area distortion in web mercator
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  11. Equal-area maps to the rescue
    Lambert azimuthal
    equal area Mollweide
    Equal Earth
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  12. FAO example
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  13. Distance perception
    http://braincrunch.tumblr.com/post/23672142073/mercators-egg
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  14. Equidistant maps to the rescue
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  15. Example: weather radar maps
    https://weather.gc.ca/radar/index_e.html?id=xsm
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  16. Who ate the poles?!
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  17. Polar stereographic
    http://www.add.scar.org/home/add6
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  18. Polar stereographic
    http://www.polarview.aq/ (also GeoServer powered)
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  19. FAO Species Distribution
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  20. The beginning of the end?
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  21. Handling all these projections

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  22. Should be simple no?
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  23. One (tragic) example
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  24. What’s going on?
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  25. And then… AUTO codes
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  26. Automate! With APH
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  27. APH step 1: which data to read
    Requested
    Read
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  28. APH step 2: cut excess data
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  29. APH step 3: data wrapping
    Requested
    Read
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  30. APH step 4: detect dateline crossing
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  31. Some side by side examples
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  32. PDC Mercator, EPSG:3832
    Antactica was here…
    Funny
    Greenland

    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  33. Lambert conf. conic, EPSG:2225
    ?!!
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  34. Datum change, ED50, EPSG:4230
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  35. UTM32N, EPSG:32632
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  36. No reprojection, but Pacific centered
    Would really like
    to see Americas
    here…
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  37. Some other hard data

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  38. Data between 0 and 360
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  39. Satellites satellites
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  40. And more satellites
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  41. Final words

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  42. APH step 2.5:dynamic densification
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  43. In summary
    FOSS4G 2018, August 29th/31st, Dar Es Salaam

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  44. That’s all folks!
    Questions?
    [email protected]

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