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opengeospatial / ogcapi-tiles

OGC API - Tiles draft specification
https://ogcapi.ogc.org/tiles
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Requirement 10B should identify the metadata fields in the 'subset of the tileset metadata' #96

Closed ghobona closed 3 years ago

ghobona commented 3 years ago

Requirement 10B says "Each element of that list SHALL contain a subset of the tileset metadata, as defined by the 2D Tile Matrix Set and Metadata standard".

However it does not identify the metadata fields that must be in that subset.

For example, one of the demos during the sprint used:

{
     "tileMatrixSetURI":"http://www.opengis.net/def/tilematrixset/OGC/1.0/WebMercatorQuad",
     "tileMatrixSetDefinition":"https://localhost/demo/ogcapi/W2019/tileMatrixSets/smerc?f=json",
     "wellKnownScaleSet":"http://www.opengis.net/def/wkss/OGC/1.0/GoogleMapsCompatible",
     "dataType":"map",
     "links":[
        {
           "href":"https://localhost/demo/ogcapi/W2019/collections/dtm_1m/styles/color/map/tiles/smerc",
           "rel":"http://www.opengis.net/def/rel/ogc/1.0/tileset",
           "type":"application/json"
        }
     ]
  }

Another demo used the example below. Notice that the example below does not use wellKnownScaleSet. The example above does not use title.

{
         "title" : "NE2_HR_LC_SR_W_DR",
         "dataType" : "map",
         "tileMatrixSetURI" : "http://www.opengis.net/def/tilematrixset/OGC/1.0/CDBGlobalGrid",
         "tileMatrixSetDefinition" : "https://localhost/ogcapi/tileMatrixSets/CDBGlobalGrid",
         "links" : [
            {
               "rel" : "http://www.opengis.net/def/rel/ogc/1.0/tileset",
               "type" : "application/json",
               "title" : "[obsolete link] CDBGlobalGrid map tileset for NE2_HR_LC_SR_W_DR (as JSON)",
               "href" : "/ogcapi/collections/NaturalEarth:raster:NE2_HR_LC_SR_W_DR/map/tiles/CDBGlobalGrid?f=json"
            },
            {
               "rel" : "http://www.opengis.net/def/rel/ogc/1.0/tileset",
               "type" : "text/html",
               "title" : "[obsolete link] CDBGlobalGrid map tileset for NE2_HR_LC_SR_W_DR (as HTML)",
               "href" : "/ogcapi/collections/NaturalEarth:raster:NE2_HR_LC_SR_W_DR/map/tiles/CDBGlobalGrid?f=html"
            }   
         ]
      }

What if another implementation omits tileMatrixSetDefinition?

We should update Requirement 10B to clarify the subset.

Perhaps the UML diagram in the 2D Tile Matrix Set and Metadata standard will indicate the mandatory (minimum required) metadata fields?

jerstlouis commented 3 years ago

@ghobona tileMatrixSetDefinition is only required for custom TMS (those that do not have a tileMatrixSetURI). title is not required. In at least one version of the TileSet metadata diagram there was a box that highlighted the portions which should be included in the list of tileset, but in general in the OGC API I believe we need to specify that required subset for high level lists better (e.g. /collections).

The JSON schema and UML do specify the mandatory fields, but I agree the specs should also specify what is required at the TileSets-List level.

ghobona commented 3 years ago

Day 2 of 2021-05 sprint brief back

The minimum required metadata was confirmed to be one of: "tileMatrixSetURI" , "tileMatrixSetDefinition", or the full tileMatrixSet object

"dataType" is also mandatory.

joanma747 commented 3 years ago

Done today in the OGC Tiles SGW telco