A.7.13 Spatial resolution - text and provided example are confusing

[NielsHoffmann]

This is an issue coming from the GeoDCAT-AP 3.0.0 pilot.

I think that technically the text is correct. However the way the paragraph is written, followed by the example can be quite confusing.

Based on this, GeoDCAT-AP specifies spatial resolution as follows:

Property dcat:spatialResolutionInMeters is used for spatial resolution when it is expressed as distance in metres.
Property dqv:hasQualityMeasurement is used for all types of spatial resolution. In such a case, the type of spatial 
resolution is specified by using property dqv:isMeasurementOf, which takes as value the relevant instance of class 
dqv:Metric defined in GeoDCAT-AP for this purpose 
(see [Instances of Metric](https://data.europa.eu/930#instances-of-metric)).
Property geodcatap:spatialResolutionAsText is used when spatial resolution is specified as free-text.

This explains that the 'Instances of Metric' can be applied, but you have to actually visit the vocabulary to see that spatialResolutionAsScale is actually one of those instances.

The paragraph then continues to explain that other types of resolution are left unmapped.

The core mapping profile of GeoDCAT-AP, following [[DCAT-AP-3](https://semiceu.github.io/GeoDCAT-AP/releases/3.0.0/
#bib-dcat-ap-3)], supports only the use property dcat:spatialResolutionInMeters, and, therefore, 
the other types of spatial resolution are left unmapped.

The example provides a statement about spatialResolutionAsScale. But it is not immediately clear ( was not to me anyway) that this is an example of the usage of an 'instance of metric'.
Additionally the conversion from the denominator 10000 to the dqv:value of 0.0001 can be quite confusing as well. It might help to explain the conversion logic stemming from the iso to dqv mapping as well.

Example 37:

# Spatial resolution as distance in metres
[] a dcat:Dataset ;
  dcat:spatialResolutionInMeters "5000"^^xsd:decimal .
# Spatial resolution as equivalent scale
[] a dcat:Dataset ;
  dqv:hasQualityMeasurement [ a dqv:QualityMeasurement ;
    dqv:isMeasurementOf geodcatap:spatialResolutionAsScale ;
    dqv:value "0.0001"^^xsd:decimal 
  ] .
Resource metadata in ISO 19139

<gmd:MD_Resolution>
  <gmd:equivalentScale>
    <gmd:MD_RepresentativeFraction>
      <gmd:denominator>
        <gco:Integer>10000</gco:Integer>
      </gmd:denominator>
    </gmd:MD_RepresentativeFraction>
  </gmd:equivalentScale>
</gmd:MD_Resolution>