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[IDV #LTA-507350]: IDV


On Tue, 22 Mar 2011, Lalitha Venkatramani wrote:

> New Client Reply: IDV
>
> Save the image as png.
> You will see the number of pixels in grib and in world projection
> When you open the image and look at properties, you will see the number of 
> pixels.
>
> Is your netcdf in latlon or native lc projection?
> If it is lc, it will be identical to grib.
> May be if you can redirect the email to the developer of this  area, we may 
> have an answer.

What you think about incresing the resolution is incorrected. When you
change the projection of the display, the size of the image you saved may
change as the area covered changed. But the resolution is still the
same.


Yuan
> > Thanks,
> Lalitha
>
> -----Original Message-----
> From: Unidata IDV Support [mailto:address@hidden]
> Sent: Tuesday, March 22, 2011 6:19 PM
> To: Lalitha Venkatramani
> Cc: address@hidden
> Subject: [IDV #LTA-507350]: IDV
>
>
>
> On Tue, 22 Mar 2011, Lalitha Venkatramani wrote:
>
> > New Client Reply: IDV
> >
> > Ok, IDV image looks great. That is the reason I am trying to understand the 
> > projection.
> >
> > As I explained in my email,
> > minimum lat is 13.8992
> >  maximum lat is 65.3821
> >  minimum lon is -144.517
> >  maximum lon is  41.9596
> >
> > Rows, columns, xres and yres ( xres and yres in meters)of the lambert 
> > conformal  projection:480 576 10700 10700
> > > Resolution in lambert conformal is 10700 meters. When I display using 
> > > IDV, I get the image with properties set to 576 X 480 pixels.
> >
> > If you convert the lambert projection to latlon , FOR THE SAME RESOLUTION 
> > 10.7 km, Latitude points are roughly,
> >
> > Latitude spans 52 degrees
> > 1 degree is 100 km. so, roughly 520 points for a 10 km resolution
> >
> > Latitude spans = 103 degrees roughly - s0, 1030 grid points for a 10 km 
> > resolution.
> >
> > When I convert the original grib file to projections/predefined/world in 
> > IDV and display in lat/lon projection.
> I see IDV shows 1203 x 918 points and the image looks great.
> >
> >
>
> I did the same convertion as you, but I am not sure how do you
> see how many points in the IDV display. What I did is to export the
> display image
> to the nc file, and then I can tell the same number of points in both
> projection.
>
>
> Yuan
> > You may notice, I use 10 km resolution which is the resolution in the grib 
> > file.
> >
> > So, I am just interested to know if you use the same resolution.
> > Can you please tell me how do you convert lambert to world?
> >
> > I see your source code, but I could not locate that area yet.
> >
> >
> > Thanks a lot,
> > Lalitha
> >
> > -----Original Message-----
> > From: Lalitha Venkatramani
> > Sent: Tuesday, March 22, 2011 5:51 PM
> > To: 'address@hidden'
> > Subject: RE: [IDV #LTA-507350]: IDV
> >
> > Ok, IDV image looks great. That is the reason I am trying to understand the 
> > projection.
> >
> > As I explained in my email ,
> > minimum lat is 13.8992
> >  maximum lat is 65.3821
> >  minimum lon is -144.517
> >  maximum lon is  41.9596
> >
> > Rows, columns, xres and yres ( xres and yres in meters)of the lambert 
> > conformal  projection:480 576 10700 10700
> > > Resolution in lambert conformal is 10700 meters. When I display using 
> > > IDV, I get the image with properties set to 576 X 480 pixels.
> >
> > If you convert the lambert projection to latlon , FOR THE SAME RESOLUTION 
> > 10.7 km,
> > Latitude points are roughtly,
> >
> > Latitude spans 52 degrees
> > 1 degree is 100 km. so, roughly 520 points for a 10 km resolution
> >
> > Latitude spans = 103 degrees roughly - s0, 1030 grid points for a 10 km 
> > resolution.
> >
> > When I  convert the original grib file to projectons/predefined/world in 
> > IDV and display in lat/lon projection. I see IDV shows 1203 x 918 points 
> > and the image looks great.
> >
> >
> > You may notice, I use 10 km resolution which is the resolution in the grib 
> > file.
> >
> > So, I am just interested to know if you use the same resolution.
> > Can you please tell em how do you convert lambert to world?
> >
> > I see your source code, but I could not locate that area yet.
> >
> >
> > Thanks a lot,
> > Lalitha
> >
> >
> >
> >
> >
> >
> >
> > -----Original Message-----
> > From: Unidata IDV Support [mailto:address@hidden]
> > Sent: Tuesday, March 22, 2011 11:53 AM
> > To: Lalitha Venkatramani
> > Cc: address@hidden
> > Subject: [IDV #LTA-507350]: IDV
> >
> > > Dear Support,
> > > I have a grib file with
> > > Min/Max Lat/Lon 13.8992 -144.517 65.3821 -41.9596
> > > Rows, columns, xres and yres ( xres and yres in meters)of the lambert 
> > > conformal  projection:480 576 10700 10700
> > > Resolution in lambert conformal is 10700 meters. When I display using 
> > > IDV, I get the image with properties set to 576 X 480 pixels.
> > >
> > > I use projectons/predefined/world in IDV and display in lat/lon 
> > > projection.
> > > I see for the converted image ( 1203 X918) pixels.
> > >
> > > If the native resolution 10.7 km ( roughly 0.1 degree is maintained, I am 
> > > wondering how we get 1203 X918 pixels.
> > >
> > > Thanks,
> > > Lalitha
> > >
> > I loaded an image and changed the projection, I didn't see any resolution 
> > change, can you give me more detail information of what you were doing?
> >
> >
> > Yuan
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: Unidata IDV Support [mailto:address@hidden]
> > > Sent: Tuesday, March 22, 2011 10:55 AM
> > > To: Lalitha Venkatramani
> > > Cc: address@hidden
> > > Subject: [IDV #LTA-507350]: IDV
> > >
> > > > Dear Support,
> > > >
> > > > I am using IDV to display grib files.
> > > >
> > > > When I convert lambert to Latlon using projectons/predefined/world, I 
> > > > get
> > > > lat/lon projection.
> > > >
> > > > Do you maintain the native resolution in this conversion?
> > > >
> > > > I can send my file and discuss more when I hear from you?
> > > >
> > > > Thanks,
> > > > Lalitha
> > > >
> > >
> > > Hi Lalitha,
> > > I don't think the resolution being changed in this conversion.
> > >
> > >
> > > Yuan
> > > >
> > >
> > >
> > > Ticket Details
> > > ===================
> > > Ticket ID: LTA-507350
> > > Department: Support IDV
> > > Priority: Normal
> > > Status: Closed
> > >
> > >
> >
> >
> > Ticket Details
> > ===================
> > Ticket ID: LTA-507350
> > Department: Support IDV
> > Priority: Normal
> > Status: Open
> >
> >
> >
> > Ticket Details
> > ===================
> > Ticket ID: LTA-507350
> > Department: Support IDV
> > Priority: Normal
> > Status: Open
> > Link:  
> > https://www.unidata.ucar.edu/esupport/staff/index.php?_m=tickets&_a=viewticket&ticketid=12991
> >
>
>
>
> Ticket Details
> ===================
> Ticket ID: LTA-507350
> Department: Support IDV
> Priority: Normal
> Status: Open
>
>
>
> Ticket Details
> ===================
> Ticket ID: LTA-507350
> Department: Support IDV
> Priority: Normal
> Status: Open
> Link:  
> https://www.unidata.ucar.edu/esupport/staff/index.php?_m=tickets&_a=viewticket&ticketid=12991
>



Ticket Details
===================
Ticket ID: LTA-507350
Department: Support IDV
Priority: Normal
Status: Open