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GFDRR / rdl-standard

The Risk Data Library Standard (RDLS) is an open data standard to make it easier to work with disaster and climate risk data. It provides a common description of the data used and produced in risk assessments, including hazard, exposure, vulnerability, and modelled loss, or impact, data.
https://docs.riskdatalibrary.org/
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Specify the coordinate reference system to be used in the Location object #201

Closed duncandewhurst closed 1 year ago

duncandewhurst commented 1 year ago

The Location definition is based on the GeoJSON specification, section 4 of which states that:

The coordinate reference system for all GeoJSON coordinates is a geographic coordinate reference system, using the World Geodetic System 1984 (WGS 84) [WGS84] datum, with longitude and latitude units of decimal degrees. This is equivalent to the coordinate reference system identified by the Open Geospatial Consortium (OGC) URN urn:ogc:def:crs:OGC::CRS84.

We should state that explicitly in the descriptions of .geometry.coordinates, .bbox and .centroid so that implementers know which CRS to use and users/tools know how to interpret coordinates.

The alternative would be to allow publishers to use a CRS of their choosing and to add a field to disclose the CRS. However, I see two issues with that approach: the risk of confusion with Resource.coordinate_system and the need for systems that consume RDLS metadata to implement conversion between CRSs in order to render locations on a map.

matamadio commented 1 year ago

First option: use WGS84 for spatial reference attributes. This remains independent from data CRS (resource attributes).

odscjen commented 1 year ago

I agree with the first option, just make is clear in the descriptions that WGS84 must be used along with decimal degrees.

@stufraser1 if you're also happy with this we can move this into the agreed and ready column