Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.
Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.
Hello,
I have problems with the findXYindexFromLatLon() method used with a Geogrid
subset.
gcs.getLatLon(0,0) gives me lat/long coordinates that I try to convert back to
XY coordinates.
But I get -1 for the X coordinate.
On the original grid, everything is fine.
The attached example reads one of the sample netCDF files from the Unidata
website. I'm using netcdfAll-4.5.jar dated March, 6 (v 4.5.5).
Does anyone see what I did wrong ? Code and output below. The "start" members
look strange.
Thanks,
Franck
------------------------------
Output :
Grid name =area
WHOLE GRID
is lat/lon system ? true
gcs bounding box : latmin=-88.927734375 latmax=88.927734375 lonmin=0.0
lonmax=358.59375
projection : LatLonProjection
width =256, height=128
X is regular ? true
X is contiguous ? true
X start : 0.0
X increment : 1.40625
Y is regular ? false
Y is contiguous ? true
Y start : -88.927734375
Y increment : 1.4004367618110236
index (0,0) --> lat/lon : -88.927734375 ; 0.0
index (1,1) --> lat/lon : -87.53870391845703 ; 1.40625
looking up lat=-87.53870391845703 lon=1.40625
index= (1, 1)
SUBGRID (latmin=-20.0 latmax=-10.0 lonmin=35.0 lonmax=45.0)
is lat/lon system ? true
gcs bounding box : latmin=-20.31112289428711 latmax=-10.505756378173828
lonmin=35.15625 lonmax=45.0
projection : LatLonProjection
width =8, height=8
X is regular ? true
X is contiguous ? true
X start : 0.0
X increment : 1.40625
Y is regular ? false
Y is contiguous ? true
Y start : 0.0
Y increment : 1.4004367618110236
index (0,0) --> lat/lon : -20.31112289428711 ; 35.15625
index (1,1) --> lat/lon : -18.910356521606445 ; 36.5625
looking up lat=-18.910356521606445 lon=36.5625
index= (-1, 1)
-------------------------
try {
GridDataset dataset =
GridDataset.open("http://www.unidata.ucar.edu/software/netcdf/examples/sresa1b_ncar_ccsm3_0_run1_200001.nc";);
GridDatatype firstGridInfo = dataset.getGrids().get(0);
System.out.println("Grid name ="+firstGridInfo.getName());
GeoGrid firstGrid = (GeoGrid) dataset.getGrids().get(0);
System.out.println("WHOLE GRID");
GridCoordSystem gcs = firstGrid.getCoordinateSystem();
System.out.println("is lat/lon system ? "+gcs.isLatLon());
LatLonRect rect = gcs.getLatLonBoundingBox();
System.out.println("gcs bounding box : latmin="+rect.getLatMin()+"
latmax="+rect.getLatMax()+" lonmin="+rect.getLonMin()+"
lonmax="+rect.getLonMax());
System.out.println("projection : "+gcs.getProjection());
System.out.println("width ="+gcs.getXHorizAxis().getSize()+",
height="+gcs.getYHorizAxis().getSize());
System.out.println("X is regular ? "+((CoordinateAxis1D)
gcs.getXHorizAxis()).isRegular());
System.out.println("X is contiguous ? "+gcs.getXHorizAxis().isContiguous());
System.out.println("X start : "+((CoordinateAxis1D)
gcs.getXHorizAxis()).getStart()) ;
System.out.println("X increment : "+((CoordinateAxis1D)
gcs.getXHorizAxis()).getIncrement()) ;
System.out.println("Y is regular ? "+((CoordinateAxis1D)
gcs.getYHorizAxis()).isRegular());
System.out.println("Y is contiguous ? "+gcs.getYHorizAxis().isContiguous());
System.out.println("Y start : "+((CoordinateAxis1D)
gcs.getYHorizAxis()).getStart()) ;
System.out.println("Y increment : "+((CoordinateAxis1D)
gcs.getYHorizAxis()).getIncrement()) ;
LatLonPoint p = gcs.getLatLon(0,0);
System.out.println("index (0,0) --> lat/lon : "+p.getLatitude()+" ;
"+p.getLongitude());
p = gcs.getLatLon(1,1);
System.out.println("index (1,1) --> lat/lon : "+p.getLatitude()+" ;
"+p.getLongitude());
System.out.println("looking up lat="+p.getLatitude()+" lon="+p.getLongitude());
int[] xy = gcs.findXYindexFromLatLon(p.getLatitude(), p.getLongitude(), null);
System.out.println("index= ("+xy[0]+", "+xy[1]+")");
// --------------------------------------------------------------------------
double latMin=-20.D, latMax=-10.D, lonMin=35.D, lonMax=45.D ;
System.out.println("\nSUBGRID (latmin="+latMin+" latmax="+latMax+"
lonmin="+lonMin+" lonmax="+lonMax+")");
LatLonRect latLonRect = new LatLonRect(
new LatLonPointImpl(latMin, lonMin),
new LatLonPointImpl(latMax, lonMax)) ;
GeoGrid gridSubset = firstGrid.subset(null, null, latLonRect, 0, 1, 1) ;
GridCoordSystem gcs2 = gridSubset.getCoordinateSystem();
rect = gcs2.getLatLonBoundingBox();
System.out.println("is lat/lon system ? "+gcs2.isLatLon());
System.out.println("gcs bounding box : latmin="+rect.getLatMin()+"
latmax="+rect.getLatMax()+" lonmin="+rect.getLonMin()+"
lonmax="+rect.getLonMax());
System.out.println("projection : "+gcs.getProjection());
System.out.println("width ="+gcs2.getXHorizAxis().getSize()+",
height="+gcs2.getYHorizAxis().getSize());
System.out.println("X is regular ? "+((CoordinateAxis1D)
gcs2.getXHorizAxis()).isRegular());
System.out.println("X is contiguous ? "+gcs2.getXHorizAxis().isContiguous());
System.out.println("X start : "+((CoordinateAxis1D)
gcs2.getXHorizAxis()).getStart()) ;
System.out.println("X increment : "+((CoordinateAxis1D)
gcs2.getXHorizAxis()).getIncrement()) ;
System.out.println("Y is regular ? "+((CoordinateAxis1D)
gcs2.getYHorizAxis()).isRegular());
System.out.println("Y is contiguous ? "+gcs2.getYHorizAxis().isContiguous());
System.out.println("Y start : "+((CoordinateAxis1D)
gcs2.getYHorizAxis()).getStart()) ;
System.out.println("Y increment : "+((CoordinateAxis1D)
gcs2.getYHorizAxis()).getIncrement()) ;
p = gcs2.getLatLon(0,0);
System.out.println("index (0,0) --> lat/lon : "+p.getLatitude()+" ;
"+p.getLongitude());
p = gcs2.getLatLon(1,1);
System.out.println("index (1,1) --> lat/lon : "+p.getLatitude()+" ;
"+p.getLongitude());
System.out.println("looking up lat="+p.getLatitude()+" lon="+p.getLongitude());
xy = gcs2.findXYindexFromLatLon(p.getLatitude(), p.getLongitude(), null);
System.out.println("index= ("+xy[0]+", "+xy[1]+")");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvalidRangeException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
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