Re: [ferret_users] station data

[Ansley Manke <ansley.b.manke@xxxxxxxx>]

Hi Nadia,
Ferret has two ways to show the values of scattered data points. 
1) You can use the SCAT2GRIDGAUSS_XY function or the SCAT2GRIDLAPLACE_XY 
function to put scattered data onto a grid.  You will need to add to 
your input data the longitude and latitude locations of the stations, in 
decimal degrees, and then call one of these functions to put the trend 
variable onto a grid which you will define.  There are examples in the 
documentation.  This method works best if there are many stations so 
that the gridding algorithm has data to work with over the area where 
you define the grid.

2) Or you can show the locations of the data without regridding, and 
color them according to the value of the trend variable, using the 
polymark.jnl script.  Again, you will need the values of the longitude 
and latitude of each station, and then you can make a map and overlay 
polygon shapes at the locations, with the polygons colored according to 
the value of the trend.  There is an example of this in the demo script 
polymark_demo.jnl; for this script we have an on-line example:

http://www.ferret.noaa.gov/Ferret/Demos/polymark_demo/polymark_demo.html

If your data is in an ascii data file, see "ASCII data, accessing" in 
the Users guide. If your data is of this form (with the longitude and 
latitude numbers filled in for all the stations)

  Trends     Longitude   Latitude   Stations     
  0.81       74.30       31.58      Lahore  
  0.51      lon.xx      lat.xx      Islamabad          
 -0.32      lon.xx      lat.xx      Karachi       
Then you could access your data with the command:

  yes? SET DATA/EZ/var="trend, xlon, ylat"/SKIP=1 filename.dat

Ansley

nadia.rehman wrote:
> Hello,  
> I have some trend values of different station data.some  
> stations have positive and some have negative trend.I want to  
> plot these trends values against their station on grids or in  
> other words i want to convert these station data information  
> onto regular grids.please help me in this regard.  
> i have data in the following format  
> Stations     Trends   Longitu
> Lahore         0.81  
> Islamabad      0.51  
> Karachi       -0.32  
> .......      .........  
>   
> and so on,,,,,,,,,,  
> Thanks  
>   
>   
>   
> Nadia Rehman Yousafzai  
> Research Fellow (Climate Section)  
> Global Change Impact Studies Centre  
> First Floor Saudi Pak tower   
> Blue Area Islamabad Pakistan  
> Ph :   92-51-9219785  
> Fax : 92-51-9219787    
>  
>  
>  
>  
> ________________________________________________________________ 
> Sent via the WebMail system at gcisc.org.pk 
>  
>  
>   
>                     
>   
--

~>   ~>   ~>   ~>   ~>   ~>   ~>   ~>   ~>   ~>   ~> 
Ansley Manke, NOAA/PMEL   ansley.b.manke@noaa.gov
7600 Sand Point Way NE, Seattle WA
Phone 206-526-6246,  FAX 206-526-6744