[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[IDV #LAG-627777]: Data are plotted to wrong locations

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 Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated.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.

  • Subject: [IDV #LAG-627777]: Data are plotted to wrong locations
  • Date: Fri, 17 Sep 2010 14:20:27 -0600
> Hi, Yuan,
> 
> Thank you very much for checking. The minor change of map position does
> not matter to me. However, the location of the data is wrong. I am
> ploting Canadian emissions, but they were plotted to US side. Attached
> is a plot I just did which shows clealy that the emissions are at US
> side. I checked the lat, lon in the netcdf file, they seem OK. Could you
> please check it again?
> 
> Many Thanks,
> 
> Junhua

Hi Junhua,

  I see the problem this time, I am guess you are using some GIS software 
packages to do the conversion. This software package has difference setting of 
y coordinate, and it is the opposite to our netcdf convention, that counting 
the 0 index at the lower left, and you need to flip the data after the 
conversion.


Yuan

> 
> 
> 
> -----Original Message-----
> From: Unidata IDV Support [mailto:address@hidden]
> Sent: September 17, 2010 3:51 PM
> To: Zhang,Junhua [Ontario]
> Cc: address@hidden
> Subject: [IDV #LAG-627777]: Data are plotted to wrong locations
> 
> > Dear IDV developer,
> >
> > I am using IDV 2.9u1 to plot some netcdf data. Originally the data is
> > in netcdf format. When I plotted it using IDV, the location of the
> > data is correct as seen in "Original_field.jpg". I then converted it
> > into other data format and did some data modification. After that I
> > converted it back to netcdf format. Unfortunately, IDV plotted the new
> 
> > netcdf data onto different locations. More specifically, it changed
> > the north-south direction as seen in "After_conversion.jpg". Please
> > noted that the data was modified. Therefore, the values are not the
> > same but the location should be the same.
> >
> > I also attached the "after conversion" netcdf file in this email. I
> > checked the data using "ncdump". It looks fine. Could you please check
> 
> > why IDV could not plot it correctly?
> >
> > Thank you in advance for your kindly help,
> >
> > Junhua
> >
> Hi Junhua,
> 
> The minor change in the map position might be caused by the lose
> precision in your conversion process, I am not sure how you control the
> precision in the new file, if it is a jave program, change the variable
> type to double instead of float may help.
> 
> 
> Yuan
> 
> Ticket Details
> ===================
> Ticket ID: LAG-627777
> Department: Support IDV
> Priority: Normal
> Status: Closed
> 
> 
> 


Ticket Details
===================
Ticket ID: LAG-627777
Department: Support IDV
Priority: Normal
Status: Closed