This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.
Greetings Roderick, The issue with your header is that you forgot to define one of the columns in your csv file. Try this header: (index)->(Latitude,Longitude,PM2_5,unknown,Time) Latitude[unit="degrees_north"],Longitude[unit="degrees_east"],PM2_5[unit="gram m-3" missing="-99.0"],unknown[unit="" missing="-99.0"],Time[fmt="yyyy-MM-dd-HH:mm:ss"] Notice that there is an unknown parameter between PM2_5 and Time...you will need to correct the name in the first and second line, as well as add the correct unit and missing value in the second line. Cheers! Sean > Full Name: Roderick Pearson > Email Address: address@hidden > Organization: None > Package Version: 3.1 build date:2012-08-31 20:26 UTC > Operating System: Linux > Hardware: Java: home: /home/IDV_3.1/jre version: 1.6.0_31 j3d:1.5.2 fcs > (build4) > Description of problem: > > There was an error loading the data: > > java.lang.NullPointerException > > I was asked by a local NGO to create some plots of pollution data in my > area. I cannot open a text point data file. The file is PM2.5 data. I > used matlab to read the raw file and format the data for IDV. It seems > pretty straight forward. I am unable to see an error in my file. > > Is this a problem with my file, IDV liking my system or how I am trying > to input the file? > > I am using the following instructions to load the file: > > http://www.unidata.ucar.edu/software/idv/docs/userguide/data/TextPointData.html > > System info > I am using IDV3.1 on Ubuntu 12.04 > >>>>>>>>> > roderick@Grady:~$ uname -a > Linux Grady 3.2.0-32-generic #51-Ubuntu SMP Wed Sep 26 21:33:09 UTC 2012 > x86_64 x86_64 x86_64 GNU/Linux > >>>>>>>>>>>>>>>>> > > The header and sample of the data > > (index->(Latitude, Longitude, PM25, Time)) > Latitude,Longitude,PM2.5[unit=g/m3 miss=-99.0],Time[fmt=yyyy-MM-dd-HH:mm:ss] > 31.768301,-106.501260,481410037, 14.0014,2012-06-01-00:00:00 > 31.765556,-106.455000,481410044, -99.0000,2012-06-01-00:00:00 > 31.758333,-106.500833,481410053, 21.1256,2012-06-01-00:00:00 > 31.768301,-106.501260,481410037, 13.4877,2012-06-01-01:00:00 > 31.765556,-106.455000,481410044, -99.0000,2012-06-01-01:00:00 > 31.758333,-106.500833,481410053, 20.0052,2012-06-01-01:00:00 > 31.768301,-106.501260,481410037, 15.2370,2012-06-01-02:00:00 > 31.765556,-106.455000,481410044, -99.0000,2012-06-01-02:00:00 > 31.758333,-106.500833,481410053, 18.2407,2012-06-01-02:00:00 > 31.768301,-106.501260,481410037, 15.0715,2012-06-01-03:00:00 > 31.765556,-106.455000,481410044, -99.0000,2012-06-01-03:00:00 > > > ****************** > Stack trace: > java.lang.NullPointerException > at visad.data.text.TextAdapter.readit(TextAdapter.java:635) > at visad.data.text.TextAdapter.<init>(TextAdapter.java:281) > at > ucar.unidata.data.point.TextPointDataSource.makeObs(TextPointDataSource.java:614) > at > ucar.unidata.data.point.TextPointDataSource.makeObs(TextPointDataSource.java:479) > at > ucar.unidata.data.point.TextPointDataSource.getSample(TextPointDataSource.java:2520) > at > ucar.unidata.data.point.PointDataSource.doMakeDataChoices(PointDataSource.java:960) > at > ucar.unidata.data.point.TextPointDataSource.doMakeDataChoices(TextPointDataSource.java:2528) > at ucar.unidata.data.DataSourceImpl.getDataChoices(DataSourceImpl.java:1845) > at ucar.unidata.data.DataManager.createDataSource(DataManager.java:1587) > at > ucar.unidata.idv.IntegratedDataViewer.createDataSource(IntegratedDataViewer.java:1980) > at > ucar.unidata.idv.IntegratedDataViewer.makeDataSource(IntegratedDataViewer.java:1897) > at > ucar.unidata.idv.IntegratedDataViewer.makeDataSource(IntegratedDataViewer.java:1831) > at > ucar.unidata.idv.IntegratedDataViewer.makeDataSource(IntegratedDataViewer.java:1804) > at ucar.unidata.idv.chooser.IdvChooser.makeDataSource(IdvChooser.java:943) > at ucar.unidata.idv.chooser.FileChooser.selectFilesInner(FileChooser.java:656) > at ucar.unidata.idv.chooser.FileChooser.selectFiles(FileChooser.java:525) > at ucar.unidata.idv.chooser.FileChooser.doLoadInThread(FileChooser.java:547) > at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) > at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) > at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) > at java.lang.reflect.Method.invoke(Unknown Source) > at ucar.unidata.util.Misc$2.run(Misc.java:1222) > at ucar.unidata.util.Misc$3.run(Misc.java:1250) > > > Ticket Details =================== Ticket ID: BVJ-740064 Department: Support IDV Priority: Normal Status: Open