Introduction

This page tries to inspect many of the different types of N-dimensional (spatiotemporal) gridded coverage topologies that could be stored in rasdaman, accompanying every case with GML Web Coverage Service (WCS) responses upon both trimming and slicing.

Despite some cases might rarely have a practical real-world example, here we want to give examples for as many allowed geometries as possible.

All responses will highlight the domainSet of each ​coverage, which will all translate to some ​gml:Grid rectified or referenceable subtype. In case of mixed rectilinear/curvilinear geometries, a non-standard so-called ReferenceableGridByArrayAndVectors type [1] will be used, for a more compact and convenient GML description.

Finally, we will assume that all the time series will be referenced by the daily-resolution (UoM=days [d]) ​ANSI-Date CRS along the temporal dimension, which (by default) has a t positive-onwards axis.

NB. The axes labels expressed in the geometric domain of a coverage are the labels of the coverage axes, which here will be labelled as increasing numbers (0, 1, 2, ...), by default. Indeed, they are independent from the axes labels of its CRS, which are instead used in the WCS GetCoverage requests.

Abbreviations:

• GML : Geographic Markup Language
• CRS : Coordinate Reference System
• SO : Single object
• RTS : Regular Time Series
• ITS : Irregular Time Series
• MRTS : Moving Regular Time Series
• MITS : Moving Irregular Time Series

[1] P. Campalani, A. Beccati, and P. Baumann. Addressing verbosity in GML 3.3 ReferenceableGrid geometries for practical use cases, 2013. Article submitted for conference proceedings.

Topologies Index

Due to the high number of possible cases, hereinafter we propose a first main table for global view.
Each cell then links to a dedicated subsection with the GML descriptions (assume default namespace is "gml").

In the 1D case, it is also clear how the gridded coverages can cover datasets which are not usually associated with the concept of grids (e.g. trajectories)

d		Description	Dim	SO	RTS	ITS	MRTS	MITS
1		Temporal series of data with no spatial reference	1D	link 	link 	link 	—-	—-
2		Point measurements (with spatial reference) on a straight line	1D
2a		… parallel to a CRS axis (2D space)	"	link 	link 	link 	link 	link 
2b		… diagonal wrt CRS axes (in 2D space)	"	link 	link 	link 	link 	link 
2c		… diagonal wrt CRS axes (in 3D space)	"	link 	link 	link 	link 	link 
2d		… diagonal in 3D space with irregular spacing	"	link 	link 	link 	link 	link 

Examples

Case 1

1D TEMPORAL SERIES OF ASPATIAL DATA

This section covers time series of point observations with no spatial reference (or where the spatial reference was not considered relevant): in this case the only distinction is whether there is a regular time step between observations, or not. In its degenerate case, the series turns to a single point.

(Attach a scan of the sketches here with all types in this subcategory?) #/1-SO

1-SO

GML coverage type	GML domain type	Coverage native CRS
RectifiedCoverage	RectifiedGrid	​http://kahlua.eecs.jacobs-university.de:8080/def/crs/OGC/0.1/ANSI-Date

• WCS trimming: ...subset=t("2013-01-01","2013-04-16")...

  <domainSet>
    <RectifiedGrid dimension="1" uomLabels="d" srsDimension="1" 
     srsName="http://kahlua.eecs.jacobs-university.de:8080/def/crs/OGC/0.1/ANSI-Date">
      <limits>
        <GridEnvelope>
          <low>1</low>
          <high>4</high>
        </GridEnvelope>
      </limits>
      <axisLabels>0</axisLabels>
      <origin>
        <Point id="ID">
          <pos>150501</pos><!-- ANSI date for 2013-01-21 -->
        </Point>
      </origin>
      <offsetVector>1</offsetVector><!-- daily data -->
    </RectifiedGrid>
  </domainSet>
  

• Slice-S

1-RTS

GML coverage type	GML domainSet	native CRS
ReferenceableCoverage	ReferenceableGridByVectors	​http://kahlua.eecs.jacobs-university.de:8080/def/crs/OGC/0.1/ANSI-Date

• WCS trimming: …
• Slice-S

  <domainSet>
  ...
  <\domainSet>
  

• Slice-T

  <domainSet>
  ...
  <\domainSet>
  

Up 

1-ITS

Up 

---

Case 2

1D SPATIAL OBSERVATIONS ON A STRAIGHT LINE

Some text.

Case 2a

… parallel to a CRS axis

2a-SO

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2a-RTS

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2a-ITS

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2a-MRTS

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2a-MITS

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Case 2b

… diagonal line, not parallel to a CRS axis

2b-SO

Up 

2b-RTS

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2b-ITS

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2b-MRTS

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2b-MITS

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Case 2c

… diagonal line in the 3D space

2c-SO

Up 

2c-RTS

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2c-ITS

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2c-MRTS

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2c-MITS

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Case 2d

… along a diagonal line in the 3D space with irregular spacing

2d-SO

Up 

2d-RTS

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2d-ITS

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2d-MRTS

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2d-MITS

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