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  1. OASIS Open Data Protocol (OData) TC
  2. ODATA-1250

GeoJSON, SRID, and LineString

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    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: V4.01_CS01
    • Fix Version/s: V4.01_CS02
    • Component/s: JSON Format
    • Labels:
    • Environment:

      Applied

    • Proposal:
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      1) Add GeoJSON-2008 as a non-normative reference and point to it (especially to http://geojson.org/geojson-spec.html#named-crs) in the bullet point mentioning the CRS object. Discourage use of CRS object as it is not part of the final GeoJSON specification.

      (Note: we already reference RFC 7946 as a normative reference, which in turn references GeoJSON-2008, but without a hyperlink. So whole point of the non-normative reference is providing the link).

      2) Remove extension to zero/one position for LineString by removing the second bullet point in the current text (see Description).

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      1) Add GeoJSON-2008 as a non-normative reference and point to it (especially to  http://geojson.org/geojson-spec.html#named-crs ) in the bullet point mentioning the CRS object. Discourage use of CRS object as it is not part of the final GeoJSON specification. (Note: we already reference RFC 7946 as a normative reference, which in turn references GeoJSON-2008, but without a hyperlink. So whole point of the non-normative reference is providing the link). 2) Remove extension to zero/one position for LineString by removing the second bullet point in the current text (see Description).
    • Resolution:
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      https://www.oasis-open.org/committees/download.php/64685/odata-json-format-v4.01-wd06-2019-02-08.docx

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      https://www.oasis-open.org/committees/download.php/64685/odata-json-format-v4.01-wd06-2019-02-08.docx

      Description

      Two issues with the JSON Format specification and GeoJSON:

      1) The JSON Format specification states

      Geography and geometry values are represented as geometry types as defined in [RFC7946, with the following modifications:

      • Keys SHOULD be ordered with type first, then coordinates, then any other keys
      • The coordinates member of a LineString can have zero or more positions
      • If the optional CRS object is present, it MUST be of type name, where the value of the name member of the contained properties object is an EPSG SRID legacy identifier.

      The CRS object is not defined in RFC7946, it was defined in the now obsolete predecessor GeoJSON-2008, and RFC7946 has explicitly removed the concept of "coordinate reference systems" (CRS) and restricts GeoJSON to World Geodetic System 1984 (WGS 84), which (fortunately) is the default for the SRID facet in OData (EPSG 4326).
       
      2) RFC7946 and GeoJSON-2008 require a LineString to have at least two positions: why do we additionally allow zero or one position? And what does that mean?

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            • Assignee:
              Unassigned
              Reporter:
              handl Ralf Handl
            • Watchers:
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              • Created:
                Updated:
                Resolved: