Dear Anotonio,
Thank you very much for your help! It works. To be honest, I had not seen your
answer in StuckOverflow before I sent the question to netcdf-java.
Have a nice day,
Beáta
From: Antonio S. Cofiño [mailto:cofinoa@xxxxxxxxx]
Sent: Friday, June 22, 2018 11:57 AM
To: netcdf-java@xxxxxxxxxxxxxxxx
Cc: Beáta Szabó-Takács <szabo.b@xxxxxxxxxxxxx>
Subject: Re: [netcdf-java] java.lang.NullPointerException at
ucar.nc2.NetcdfFileWriter.write(NetcdfFileWriter.java:939)
Dear Beáta,
I have answered to you at StackOverflow:
You are declaring your variables twice, once as static:
public static Variable time;
and other in the local scope of your switch:
Variable time = ncfile.addVariable(...);
and therefore you are "losing" the initialized Object in the local scope.
Replace the local declaration by just the assigning the initialized Object to
the static variable declaration:
time = ncfile.addVariable(...);
Regards
Antonio S. Cofiño
P.S.:
I have already answered to your question at StackOverflow:
https://stackoverflow.com/questions/50964120/how-can-i-initialize-the-netcdf-varables-as-global-variables-to-avoid-java-lang
On 22/06/18 08:43, Beáta Szabó-Takács wrote:
Dear All,
I would like to write a netCDF4 file in Java based on
https://www.unidata.ucar.edu/software/thredds/current/netcdf-java/tutorial/NetcdfWriting.html.
I have a lot of variables and I would like to select just some and write only
them to netcdf file. I tried to solve this by the the following way:
public class JavaDB {
public static Variable time;
public static Variable cloud_1st;
public static Variable cloud_2nd;
public static Variable cloud_3th;
public static Variable cloud_4th;
public static Variable cloud_5th;
public static Variable Layer_1st;
public static Variable Layer_2nd;
public static Variable Layer_3th;
public static Variable Layer_4th;
public static Variable Layer_5th;
public static Variable CBN;
public static void getDataNC(String location, ArrayList<Integer> Values) throws
Exception{
String version = System.getProperty("java.version");
NetcdfFileWriter ncfile =
NetcdfFileWriter.createNew(NetcdfFileWriter.Version.netcdf4, location, null);
// add dimensions
Dimension heightDim = ncfile.addDimension(null,"height",1539);
Dimension timeDim = ncfile.addUnlimitedDimension("time");
//define variables
for(int k=0; k<Values.size(); k++){
switch(Values.get(k)){
case 1: Variable time = ncfile.addVariable(null, "time",
DataType.DOUBLE,"time");
time.addAttribute( new Attribute("units", "days since
1970-01-01"));
break;
case 2: Variable cloud_1st =
ncfile.addVariable(null,"cloud_1st", DataType.INT,"time");
cloud_1st.addAttribute( new Attribute("long_name",
"cloud amount in 1st layer1"));
cloud_1st.addAttribute( new Attribute("units", "octa"));
cloud_1st.addAttribute(new
Attribute("_FillValue",-9999));
cloud_1st.addAttribute(new Attribute("Vertical
Visibility",9));
cloud_1st.addAttribute(new Attribute("No enough
data",99));
break;
case 3: Variable cloud_2nd =
ncfile.addVariable(null,"cloud_2nd", DataType.INT,"time");
cloud_2nd.addAttribute( new Attribute("long_name",
"cloud amount in 2nd layer"));
cloud_2nd.addAttribute( new Attribute("units", "octa"));
cloud_2nd.addAttribute(new
Attribute("_FillValue",-9999));
cloud_2nd.addAttribute(new Attribute("Vertical
Visibility",9));
cloud_2nd.addAttribute(new Attribute("No enough
data",99));
break;
case 4: Variable cloud_3th =
ncfile.addVariable(null,"cloud_3th", DataType.INT,"time");
cloud_3th.addAttribute( new Attribute("long_name",
"cloud amount in 3th layer"));
cloud_3th.addAttribute( new Attribute("units", "octa"));
cloud_3th.addAttribute(new
Attribute("_FillValue",-9999));
cloud_3th.addAttribute(new Attribute("Vertical
Visibility",9));
cloud_3th.addAttribute(new Attribute("No enough
data",99));
break;
case 5: Variable cloud_4th = ncfile.addVariable(null,
"cloud_4th", DataType.INT, "time");
cloud_4th.addAttribute( new Attribute("long_name",
"cloud amount in 4th layer"));
cloud_4th.addAttribute( new Attribute("units", "octa"));
cloud_4th.addAttribute(new
Attribute("_FillValue",-9999));
cloud_4th.addAttribute(new Attribute("Vertical
Visibility", 9));
cloud_4th.addAttribute(new Attribute("No enough
data",99));
break;
case 6: Variable cloud_5th = ncfile.addVariable(null,
"cloud_5th", DataType.INT, "time");
cloud_5th.addAttribute( new Attribute("long_name",
"cloud amount in 5th layer"));
cloud_5th.addAttribute( new Attribute("units", "octa"));
cloud_5th.addAttribute(new
Attribute("_FillValue",-9999));
cloud_5th.addAttribute(new Attribute("Vertical
Visibility",9));
cloud_5th.addAttribute(new Attribute("no enough
data",99));
break;
case 7: Variable Layer_1st =
ncfile.addVariable(null,"Layer_1st",DataType.INT,"time");
Layer_1st.addAttribute(new Attribute("long_name", "1st
cloud layer height"));
Layer_1st.addAttribute(new Attribute("units","meter"));
Layer_1st.addAttribute(new
Attribute("_FillValue",-9999));
break;
case 8: Variable Layer_2nd =
ncfile.addVariable(null,"Layer_2nd",DataType.INT,"time");
Layer_2nd.addAttribute(new Attribute("long_name", "2nd
cloud layer height"));
Layer_2nd.addAttribute(new Attribute("units","meter"));
Layer_2nd.addAttribute(new
Attribute("_FillValue",-9999));
break;
case 9: Variable Layer_3th =
ncfile.addVariable(null,"Layer_3th",DataType.INT,"time");
Layer_3th.addAttribute(new Attribute("long_name", "3th
cloud layer height"));
Layer_3th.addAttribute(new Attribute("units","meter"));
Layer_3th.addAttribute(new
Attribute("_FillValue",-9999));
break;
case 10: Variable Layer_4th =
ncfile.addVariable(null,"Layer_4th",DataType.INT,"time");
Layer_4th.addAttribute(new Attribute("long_name",
"4th cloud layer height"));
Layer_4th.addAttribute(new
Attribute("units","meter"));
Layer_4th.addAttribute(new
Attribute("_FillValue",-9999));
break;
case 11: Variable Layer_5th =
ncfile.addVariable(null,"Layer_5th",DataType.INT,"time");
Layer_5th.addAttribute(new Attribute("long_name",
"5th cloud layer height"));
Layer_5th.addAttribute(new
Attribute("units","meter"));
Layer_5th.addAttribute(new
Attribute("_FillValue",-9999));
break;
case 12: Variable CBN =
ncfile.addVariable(null,"CBN",DataType.INT,"time");
CBN.addAttribute(new Attribute("long_name","cloud
base number"));
CBN.addAttribute(new Attribute("units", "number"));
CBN.addAttribute(new Attribute("no significant
backscatter",0));
CBN.addAttribute(new Attribute("obscuration but no
cloud",4));
CBN.addAttribute(new Attribute("transparent
obscuration",5));
CBN.addAttribute(new Attribute("_FillValue",-9));
break;
}
}
ncfile.create();
try{
ArrayDouble.D1 timeData = new ArrayDouble.D1(countLinesResult);
ArrayInt.D1 cloudL1Data = new ArrayInt.D1(countLinesResult);
Index ima = cloudL1Data.getIndex();
ArrayInt.D1 cloudL2Data = new ArrayInt.D1(countLinesResult);
ArrayInt.D1 cloudL3Data = new ArrayInt.D1(countLinesResult);
ArrayInt.D1 cloudL4Data = new ArrayInt.D1(countLinesResult);
ArrayInt.D1 cloudL5Data = new ArrayInt.D1(countLinesResult);
ArrayInt.D1 cLayer1Data = new ArrayInt.D1(countLinesResult);
ArrayInt.D1 cLayer2Data = new ArrayInt.D1(countLinesResult);
ArrayInt.D1 cLayer3Data = new ArrayInt.D1(countLinesResult);
ArrayInt.D1 cLayer4Data = new ArrayInt.D1(countLinesResult);
ArrayInt.D1 cLayer5Data = new ArrayInt.D1(countLinesResult);
ArrayInt.D1 CBNData = new ArrayInt.D1(countLinesResult);
for (int timeIdx = 0; timeIdx < countLinesResult;timeIdx++){
for(int k=0; k<Values.size(); k++){
// System.out.println(Values.get(k));
if(Values.get(k)==1){
timeData.setDouble(timeIdx,tdate.get(timeIdx));}
if(Values.get(k)==2){
cloudL1Data.setInt(ima.set(timeIdx),
cloud_layer_1st.get(timeIdx));}
if(Values.get(k)==3){
cloudL2Data.setInt(ima.set(timeIdx),
cloud_layer_2nd.get(timeIdx));}
if(Values.get(k)==4){
cloudL3Data.setInt(ima.set(timeIdx),
cloud_layer_3th.get(timeIdx));}
if(Values.get(k)==5){
cloudL4Data.setInt(ima.set(timeIdx),
cloud_layer_4th.get(timeIdx));}
if(Values.get(k)==6){
cloudL5Data.setInt(ima.set(timeIdx),
cloud_layer_5th.get(timeIdx));}
if(Values.get(k)==7){
cLayer1Data.setInt(ima.set(timeIdx),
LayerC_1st.get(timeIdx));}
if(Values.get(k)==8){
cLayer2Data.setInt(ima.set(timeIdx),
LayerC_2nd.get(timeIdx));}
if(Values.get(k)==9){
cLayer3Data.setInt(ima.set(timeIdx),
LayerC_3th.get(timeIdx));}
if(Values.get(k)==10){
cLayer4Data.setInt(ima.set(timeIdx),
LayerC_4th.get(timeIdx));}
if(Values.get(k)==11){
cLayer5Data.setInt(ima.set(timeIdx),
LayerC_5th.get(timeIdx));}
if(Values.get(k)==12){
CBNData.setInt(ima.set(timeIdx),nbcb.get(timeIdx));}
}
}
// write the data into netCDF file
for(int k=0; k<Values.size(); k++){
if(Values.get(k)==1){
ncfile.write(time, timeData);}
if(Values.get(k)==2){
ncfile.write(cloud_1st, cloudL1Data);}
if(Values.get(k)==3){
ncfile.write(cloud_2nd, cloudL2Data);}
if(Values.get(k)==4){
ncfile.write(cloud_3th, cloudL3Data);}
if(Values.get(k)==5){
ncfile.write(cloud_4th, cloudL4Data);}
if(Values.get(k)==6){
ncfile.write(cloud_5th, cloudL5Data);}
if(Values.get(k)==7){
ncfile.write(Layer_1st, cLayer1Data);}
if(Values.get(k)==8){
ncfile.write(Layer_2nd, cLayer2Data);}
if(Values.get(k)==9){
ncfile.write(Layer_3th, cLayer3Data);}
if(Values.get(k)==10){
ncfile.write(Layer_4th, cLayer4Data);}
if(Values.get(k)==11){
ncfile.write(Layer_5th, cLayer5Data);}
if(Values.get(k)==12){
ncfile.write(CBN,CBNData);}
}
}catch(Exception e){
e.printStackTrace();}
finally{
try{
ncfile.close();
}catch(IOException ex){
ex.printStackTrace();
}
}
But after I run the code I get java.lang.NullPointerException at
ucar.nc2.NetcdfFileWriter.write(NetcdfFileWriter.java:939). I tried to solve it
with define global variables size e.g public static Variable time = new
Variable(); but it is not possible. Could you please informe me how I should
fix this issue?
Thank you for your help in adavnce!
Best regards,
Beata
_______________________________________________
NOTE: All exchanges posted to Unidata maintained email lists are
recorded in the Unidata inquiry tracking system and made publicly
available through the web. Users who post to any of the lists we
maintain are reminded to remove any personal information that they
do not want to be made public.
netcdf-java mailing list
netcdf-java@xxxxxxxxxxxxxxxx<mailto:netcdf-java@xxxxxxxxxxxxxxxx>
For list information or to unsubscribe, visit:
http://www.unidata.ucar.edu/mailing_lists/
