[gradsusr] lon lat to km

Sat Feb 2 02:41:00 EST 2013

Dear Mr. Jeff

Thank you very much for your explanation,
but I am very sorry, I still do not get it,

I made new script

'reinit'
'open try2.ctl'
'set grads off'
'set mproj latlon'
'set mpdset hires'
'set gxout shaded'
'set grid on'
'set lon 100  101'
'set lat -1  0'
'define dx = *6.371e3**cos(-1*(3.14159/180))*cdiff(100,0)*(3.14159/180)'
'define dy = *6.371e3**cdiff(-1,0)*(3.14159/180))'
'define xdist = [(100-101)/0.004492369]*[dx/2]'
'define ydist = [(-1-0)/0.004522556]*[dy/2]'
'set z 5'
'set t 1'
'd ref'

I checked grads document and I found that 6.371e3 is radius of the earth
(6371 to 6374 km)*.*
*
*
*I tried to change "*6.371e3" to "0e10" which is mean 0 to 10 km)
But still the program did not run normally.

I changed the value of lon and lat in script with 100 and -1.
but still I got error.

Please help me to solve it.

Thank you very much
Best regards,
wendi

On Sat, Feb 2, 2013 at 2:21 AM, Jeff Duda <jeffduda319 at gmail.com> wrote:

> Wendi,
> You need to run those two define commands at the top of my previous email
> before attempting to define the xdist and ydist fields.  Also, since I can
> see your control file information, I can see that dlon is 0.004492369 and
> dlat is  0.004522556.  So substitute those two values into your expressions
> for xdist and ydist also.
>
> Jeff
>
>
> On Fri, Feb 1, 2013 at 4:36 AM, wendi harjupa <wendiharjupa at gmail.com>wrote:
>
>> Dear Mr. Jeff
>>
>> I have tried to use the scipt which you suggested,
>> But, still I could not do it. Would you help me more...
>>
>> here I send my gs file :
>>
>> 'reinit'
>> 'open try2.ctl'
>> 'set grads off'
>> 'set mproj latlon'
>> 'set mpdset hires'
>> 'set gxout shaded'
>> 'set grid on'
>> 'set lon 100  101'
>> 'set lat 0  1'
>> 'define xdist = [(lon 99.7)/dlon]*[dx/2]'
>> 'define ydist = [(lat -1.02)/dlat]*[dy/2]'
>> 'set z 5'
>> 'set t 1'
>> 'd ref'
>>
>> Below is my ctl file :
>>
>> DSET 1013.dat
>> TITLE  RADAR
>> OPTIONS  TEMPLATE LITTLE_ENDIAN
>> UNDEF  -1000
>> XDEF    321 LINEAR    99.688120996    0.004492369
>> YDEF    321 LINEAR    -1.083708891    0.004522556
>> ZDEF    39  LINEAR   1.0 0.5
>> TDEF    15 LINEAR 13:00Z10apr2004  4mn
>> VARS    2
>> ref 39  99  Reflectivity(dBZ)
>> vel 39  99  Doppler Velocity(m/s)
>> ENDVARS
>>
>>
>> Would you check my gs file, is there something that I have to revise??
>>
>> Thank you very much.
>>
>> Best regards,
>> wendi
>>
>>
>>
>> On Fri, Feb 1, 2013 at 10:34 AM, Jeff Duda <jeffduda319 at gmail.com> wrote:
>>
>>> These commands will help.
>>>
>>> 'define dx = 6.371e3*cos(lat*(3.14159/180))*cdiff(lon,x)*(3.14159/180)'
>>> 'define dy = 6.371e3*cdiff(lat,y)*(3.14159/180))'
>>>
>>> They define grid increments in terms of spatial distance rather than
>>> geographic distance.  If you're trying to change the axes and tick marks,
>>> you'll have to define an origin and define your x and y distances based on
>>> that.  For instance, if you set your lower left domain corner (latitude 0
>>> and longitude 100), then you can define your coordinate distances using
>>>
>>> 'define xdist = [(lon-100)/dlon]*[dx/2]'
>>> 'define ydist = [(lat-0)/dlat]*[dy/2]'
>>>
>>> I think this should work, but I haven't tested it myself, so I don't
>>> know.  dlon and dlat are the step values from the XDEF and YDEF lines of
>>> the control file, respectively.
>>>
>>> Jeff Duda
>>>
>>> On Thu, Jan 31, 2013 at 7:02 AM, wendi harjupa <wendiharjupa at gmail.com>wrote:
>>>
>>>> Dear Sir/Madam
>>>>
>>>> I need help
>>>> I have problem with grads command,
>>>> I am not well understand with command gr2XY,
>>>>
>>>> Actually I want to convert the lon 100  to 101, and lat 0 to 1 to
>>>> distance (km)
>>>> let think that lon 100 is 0 km, and lat 0 is 0 km,
>>>>
>>>> what command I can use to convert lon and lat to km?
>>>>
>>>> Thank you very much for your help
>>>>
>>>> best regards,
>>>> --
>>>> -------------
>>>> Wendi Harjupa. ST
>>>> Shimane University Graduate School of Engineering Sciences
>>>> Department of Electronic Control Systems
>>>> Remote Sensing Laboratory
>>>> s119447
>>>> Cellphone : +81-080-4268-6676
>>>> email : wendi at rslab.riko.shimane-u.ac.jp
>>>>
>>>> _______________________________________________
>>>> gradsusr mailing list
>>>> gradsusr at gradsusr.org
>>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>>
>>>>
>>>
>>>
>>> --
>>> Jeff Duda
>>> Graduate research assistant
>>> University of Oklahoma School of Meteorology
>>> Center for Analysis and Prediction of Storms
>>>
>>> _______________________________________________
>>> gradsusr mailing list
>>> gradsusr at gradsusr.org
>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>
>>>
>>
>>
>> --
>> -------------
>> Wendi Harjupa. ST
>> Shimane University Graduate School of Engineering Sciences
>> Department of Electronic Control Systems
>> Remote Sensing Laboratory
>> s119447
>> Cellphone : +81-080-4268-6676
>> email : wendi at rslab.riko.shimane-u.ac.jp
>>
>> _______________________________________________
>> gradsusr mailing list
>> gradsusr at gradsusr.org
>> http://gradsusr.org/mailman/listinfo/gradsusr
>>
>>
>
>
> --
> Jeff Duda
> Graduate research assistant
> University of Oklahoma School of Meteorology
> Center for Analysis and Prediction of Storms
>
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr
>
>

-- 
-------------
Wendi Harjupa. ST
Shimane University Graduate School of Engineering Sciences
Department of Electronic Control Systems
Remote Sensing Laboratory
s119447
Cellphone : +81-080-4268-6676
email : wendi at rslab.riko.shimane-u.ac.jp
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