Ticket #804 (closed Defect: worksforme)

Opened 7 years ago

Last modified 7 years ago

dm4-geomaps: latitude and longitude values should not be composite of a geo coordinate but aggregates

Reported by: Malte Owned by: jri
Priority: Major Milestone: Release 4.7
Component: DeepaMehta Standard Distribution Version: 4.6.1
Keywords: Cc: Malte
Complexity: 3 Area:
Module: deepamehta-geomaps

Description

... if they would be (as they currently are modelled) both values (lat, lng) could'nt be indexed as "Keys" (subsequent errors thrown "More than one element") and thus, latitude/longitude values could not be re-used across geo-coordinate items (and ultimately not across domain topics).

Latitude and Longitude topics should be indexes as Keys and should "aggregate" a Geo Coordinate. Currently, if one tries to re-use lat/lng values acroos geo-coordinates, "Geo Coordinate" topics which only share one value with an existing topic can not at all written to DB (cause of the exception mentioned above).

In fact, each of these values actually are globally unique, as they are part of a well defined coordinate reference system identified as "EPSG::3857" (see http://www.epsg-registry.org/report.htm?type=selection&entity=urn:ogc:def:crs:EPSG::3857&reportDetail=short&style=urn:uuid:report-style:default-with-code&style_name=OGP%20Default%20With%20Code&title=EPSG:3857) also known as WGS 84 or Pseudo-Mercator.

Thanks for your support!

Change History

comment:1 Changed 7 years ago by Malte

  • Status changed from new to closed
  • Resolution set to worksforme

Having the "composite" and "aggregate" semantics of the dm4-core API in mind, geo coordinate values could but may be should not be aggregated (and thus not be keys and thus their child values not be unique).

I changed the model of the dm4-wdtk 'geo-fronts' branch accordingly, geo coordinate values are not considered unique anymore.

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