See test case below. foo.ncml defines a rectilinear, t-y-x, 4x4x4 grid
named "foo". fooSubGrid is the 2x2x2 "central" subset of fooGrid.
foo.ncml:
<?xml version="1.0" encoding="UTF-8"?>
<netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";>
<dimension name="time" length="4" />
<dimension name="lat" length="4" />
<dimension name="lon" length="4" />
<dimension name="bnds" length="2" />
<variable name="time" shape="time" type="double">
<attribute name="units" type="String" value="days since 1850-01-01" />
<attribute name="calendar" type="String" value="standard" />
<attribute name="bounds" type="String" value="time_bnds" />
<values>15.5 45.0 74.5 105.0</values>
</variable>
<variable name="time_bnds" shape="time bnds" type="double">
<values>0.0 31.0 31.0 59.0 59.0 90.0 90.0 120.0</values>
</variable>
<variable name="lat" shape="lat" type="double">
<attribute name="units" type="String" value="degrees_north" />
<attribute name="bounds" type="String" value="lat_bnds" />
<values>-54 9 54 81</values>
</variable>
<variable name="lat_bnds" shape="lat bnds" type="double">
<values>-90 -18 -18 36 36 72 72 90</values>
</variable>
<variable name="lon" shape="lon" type="double">
<attribute name="units" type="String" value="degrees_east" />
<attribute name="bounds" type="String" value="lon_bnds" />
<values>18 72 162 288</values>
</variable>
<variable name="lon_bnds" shape="lon bnds" type="double">
<values>0 36 36 108 108 216 216 360</values>
</variable>
<variable name="foo" shape="time lat lon" type="float">
<values start="1.0" increment="1.0" />
</variable>
</netcdf>
Foo.java:
public static void main(String[] args) throws IOException,
InvalidRangeException {
File fooNcmlFile = new File("foo.ncml");
NetcdfDataset fooDataset =
NetcdfDataset.openDataset(fooNcmlFile.getAbsolutePath());
try {
GridDataset fooGridDataset = new GridDataset(fooDataset);
GridDatatype fooGrid = fooGridDataset.findGridDatatype("foo");
CoordinateAxis1D fooTimeAxis =
fooGrid.getCoordinateSystem().getTimeAxis1D();
CoordinateAxis1D fooLatAxis = (CoordinateAxis1D)
fooGrid.getCoordinateSystem().getYHorizAxis();
CoordinateAxis1D fooLonAxis = (CoordinateAxis1D)
fooGrid.getCoordinateSystem().getXHorizAxis();
// Expected: [0.0, 31.0, 59.0, 90.0, 120.0]
// Actual: [0.0, 31.0, 59.0, 90.0, 120.0]
System.out.println(Arrays.toString(fooTimeAxis.getCoordEdges()));
// Expected: [-90.0, -18.0, 36.0, 72.0, 90.0]
// Actual: [-90.0, -18.0, 36.0, 72.0, 90.0]
System.out.println(Arrays.toString(fooLatAxis.getCoordEdges()));
// Expected: [0.0, 36.0, 108.0, 216.0, 360.0]
// Actual: [0.0, 36.0, 108.0, 216.0, 360.0]
System.out.println(Arrays.toString(fooLonAxis.getCoordEdges()));
Range middleRange = new Range(1, 2);
GridDatatype fooSubGrid = fooGrid.makeSubset(null, null,
middleRange, null, middleRange, middleRange);
CoordinateAxis1D fooSubTimeAxis =
fooSubGrid.getCoordinateSystem().getTimeAxis1D();
CoordinateAxis1D fooSubLatAxis = (CoordinateAxis1D)
fooSubGrid.getCoordinateSystem().getYHorizAxis();
CoordinateAxis1D fooSubLonAxis = (CoordinateAxis1D)
fooSubGrid.getCoordinateSystem().getXHorizAxis();
// Expected: [31.0, 59.0, 90.0]
// Actual: [30.25, 59.75, 89.25]
System.out.println(Arrays.toString(fooSubTimeAxis.getCoordEdges()));
// Expected: [-18.0, 36.0, 72.0]
// Actual: [-13.5, 31.5, 76.5]
System.out.println(Arrays.toString(fooSubLatAxis.getCoordEdges()));
// Expected: [36.0, 108.0, 216.0]
// Actual: [27.0, 117.0, 207.0]
System.out.println(Arrays.toString(fooSubLonAxis.getCoordEdges()));
} finally {
fooDataset.close();
}
}
