@Override
public DatasetMetadata queryMetadata(String uri, String referential) throws IOException {
DatasetMetadata md = new DatasetMetadata();
// Coordinate system
Dataset dataset = findDataset(uri, referential);
if (dataset == null) {
throw new IOException(String.format("Could not find dataset %s", uri));
}
log.trace("Querying spatial axes of {}", dataset);
List<TimeSlice> tss = datasetDao.getTimeSlices(dataset.getId());
GridProjected grid = queryGrid(dataset, tss);
TimeAxis timeAxis = queryTimeAxis(dataset, tss);
md.setCsys(new QueryCoordinateSystem(grid, timeAxis));
// Variable names
log.trace("Querying variable names of {}", dataset);
List<String> bandNames = new ArrayList<>();
for (Band b : datasetDao.getBands(dataset.getId())) {
bandNames.add(b.getName());
}
// In the current RSA, all datasets have coordinate axes (1D variables)
// x, y and time
bandNames.add("time");
bandNames.add("y");
bandNames.add("x");
md.setVariables(bandNames);
return md;
}
private GridProjected queryGrid(Dataset dataset, List<TimeSlice> tss) throws IOException {
// Create a bounding box that encompasses all time slices.
Box smbounds = timeSliceUtil.aggregateBounds(tss);
if (smbounds == null) throw new IOException("Could not determine bounds: no time slices.");
BoxReal bounds = new BoxReal(2);
bounds.getMin().setX(smbounds.getXMin());
bounds.getMin().setY(smbounds.getYMin());
bounds.getMax().setX(smbounds.getXMax());
bounds.getMax().setY(smbounds.getYMax());
// Resolution.
double cellSize = dataset.getResolution().toDouble();
VectorReal resolution = VectorReal.createEmpty(2);
resolution.setX(cellSize);
resolution.setY(cellSize);
// All files for a given dataset share a common coordinate system. So,
// we can just open one of the blank files and take a peek at it.
CoordinateSystem srs = null;
List<Band> bands = datasetDao.getBands(dataset.getId());
for (Band b : bands) {
Path blankTilePath = bandUtil.getBlankTilePath(dataset, b);
if (Files.notExists(blankTilePath)) continue;
NetcdfDataset ncd = NetcdfDataset.openDataset(blankTilePath.toString());
try {
ncd.enhance();
srs = ncd.getCoordinateSystems().get(0);
break;
} finally {
ncd.close();
}
}
if (srs == null) {
throw new IOException(
String.format(
"Could not determine "
+ "coordinate system for dataset %s. There may be no "
+ "tiles, or the bounds in the database may not match the "
+ "tiles stored on disk.",
dataset));
}
return new GridProjected(bounds, resolution, srs);
}