geotools-devel

[Geotools-devel] elevation and temporal coordinates

[<bu...@me...>]

Hi,

I committed a version of the gpx datastore, that is also able to write a 
gpx file. However, there are some questions, that are not really clear 
for me.

First is about the CRS to use, when elevation and/or temporal 
coordinates are present. Now this is what I did:

public static final DefaultTemporalCRS gpxTemporalCRS =
    new DefaultTemporalCRS("UNIX",
          DefaultTemporalDatum.UNIX,
          DefaultTimeCS.DAYS);

public static final CoordinateReferenceSystem gpxCRS =
    new DefaultCompoundCRS("gpxCrs",
          DefaultGeographicCRS.WGS84,
          DefaultVerticalCRS.ELLIPSOIDAL_HEIGHT,
          gpxTemporalCRS);

Is it the way to do this?

I also created a TemporalCoordinate class, which is the 4D extension of 
the JTS Coordinate class, and the appropriate CoordinateSequence and 
CoordinateSequenceFactory.

Thank you,
Peter

Re: [Geotools-devel] elevation and temporal coordinates

[Martin D. <mar...@ge...>]

Bolla Péter a écrit :
> public static final DefaultTemporalCRS gpxTemporalCRS =
>     new DefaultTemporalCRS("UNIX",
>           DefaultTemporalDatum.UNIX,
>           DefaultTimeCS.DAYS);
> 
> public static final CoordinateReferenceSystem gpxCRS =
>     new DefaultCompoundCRS("gpxCrs",
>           DefaultGeographicCRS.WGS84,
>           DefaultVerticalCRS.ELLIPSOIDAL_HEIGHT,
>           gpxTemporalCRS);
> 
> Is it the way to do this?

Is it the way for every kind of height except ELLIPSOIDAL_HEIGHT. This one
should be treated especially (as required by ISO 19111, this is not something I
invented). You should create a 3-dimensional GeographicCRS instead of
concatenating a 2-dimensional GeographicCRS with a VerticalCRS["ellipsoidal
height"]. I suggest to just replace the last declaration by the following one:

public static final CoordinateReferenceSystem gpxCRS =
    new DefaultCompoundCRS("gpxCrs",
          DefaultGeographicCRS.WGS84_3D,
          gpxTemporalCRS);


	Martin