Re: updates to the Best Practice document

Hi Simon- That's useful ... what's the copyright associated with the ISO
text?
On Thu, 8 Sep 2016 at 04:43, <Simon.Cox@csiro.au> wrote:

> The recent revision of ISO 19109 added material on Coverages (as well as
> Observations) that was not in the original, recognising that coverages are
> important tools for some applications. You might also like to consider
> these sections from ISO 19109:2013
>
>
>
> 7.2.2 Coverages
>
>
>
> Many aspects of the real-world may be represented as features whose
> properties are single-valued and static. These conventional features
> provide a model of the world in terms of discrete objects located in it.
> However, in some applications it is more useful to use a model focussing on
> the variation of property values in space and time, formalized as
> coverages. Users of geographic information may utilize both viewpoints.
> While coverages are themselves strictly features as well, it is common to
> contrast coverages and non-coverage features when discussing the
> functionality provided by each viewpoint. In the following discussion the
> name ‘feature’ refers to non-coverage features.
>
> 
>
> The feature and coverage representations may be related in several ways:
>
>
>
> — signal processing to find and characterize features: signals in
> coverages may provide evidence for the existence, location and type of
> features, detected through modelling and interpretation;
>
>
>
> EXAMPLE 1 Patterns of colour or other radiance bands within a
> remotely-sensed image may be used to infer the existence of specific
> objects or features on the ground.
>
>
>
> EXAMPLE 2 Signals in a geophysical borehole log may be used to infer the
> presence of particular rock-units at underground locations.
>
>
>
> — coverage-typed feature properties: feature properties whose value vary
> within the scope of a feature may be described as coverages whose domain
> extent is the geometry of the feature;
>
>
>
> EXAMPLE 3 The variation of concentration of a particular ore-mineral
> within a mine may be described as a spatial function or coverage within the
> spatial limits of the mine.
>
>
>
> — features sample a coverage: the values of a common property of a set of
> features provide a discrete sampling of a coverage, whose range type is the
> property, and whose domain is the aggregate geometry of the set of features.
>
>
>
> EXAMPLE 4 The temperature at a set of weather stations may be compiled to
> show the spatial variation of temperature across the region where the
> stations are located.
>
>
>
> A constraint in the latter two cases is that a property-type from a
> feature catalogue is the range-type of a coverage description in the same
> universe of discourse.
>
>
>
> The case of features having property values that vary within the scope of
> the feature can be described using the general feature model (7.5.8).
>
>
>
> While the coverage model is described in detail in ISO 19123, an
> application schema may include both feature- and coverage-types.
>
> NOTE The feature and coverage viewpoints are related to (though not
> identical with) the so-called ‘vector’ and ‘raster’ approaches from
> traditional GIS implementations.
>
>
>
> Then, immediately following:
>
>
>
> 7.2.3 Properties and observations
>
>
>
> Property values are associated with features and coverages. In the case of
> features, a property value is associated with a classified object. In the
> case of coverages, a property value is associated with a position in the
> domain.
>
>
>
> Later
>
>
>
> 8.8 Rules for use of coverage functions
>
>
>
> Coverage functions are used to describe characteristics of real-world
> phenomena that vary over space and/or time. Typical examples are
> temperature, elevation and precipitation. A coverage contains a set of such
> values, each associated with one of the elements in a spatial, temporal or
> spatio-temporal domain. Typical spatial domains are point sets (e.g. sensor
> locations), curve sets (e.g. contour lines), grids (e.g. orthoimages,
> elevation models), etc. A property whose value varies as a function of time
> may be represented as a temporal coverage or time-series. A continuous
> coverage is associated with a method for interpolating values at spatial
> positions between the elements of a domain, e.g. between two points or
> contour lines.
>
>
>
> *From:* Jeremy Tandy [mailto:jeremy.tandy@gmail.com]
> *Sent:* Thursday, 8 September 2016 7:17 AM
> *To:* SDW WG Public List <public-sdw-wg@w3.org>
> *Subject:* updates to the Best Practice document
>
>
>
> Following today's BP call, I've now added into the BP doc what I was
> talking about:
>
>
>
> * A section explaining about Coverages [1] (thanks to Jon Blower; I
> repurposed one of his Melodies blog posts!)
>
> * The beginnings of a section that tries to provide a linear path through
> the decisions you might make when publishing data: "How to use these best
> practices" [2] ... this tries to combine SDW and DWBP best practices into a
> coherent whole ... that said, I've found it really hard to plan this out; I
> think it's working (& there's more in my head that I unfortunately don't
> have time to write before I disappear tomorrow ... leaving no more time for
> update before TPAC.
>
>
>
> Hope these additions are worthwhile.
>
>
>
> Jeremy
>
>
>
> [1]: http://w3c.github.io/sdw/bp/#coverages
>
> [2]: http://w3c.github.io/sdw/bp/#how-to-use
>