[ncl-talk] Problem with plotting station data in DMS-coordinates

[Dennis Shea]

The following is fine
   dd = dd*(-1.0)
However, the following is preferred
 dd = -dd

On Sun, Feb 3, 2019 at 4:27 PM MeteoBB <info at meteo-bb.de> wrote:

> Hi Dennis,
>
> thx. Seems to be work fine except for cases where the lat or lon is in
> western or southern hemisphere.
> I added some code for this and so this is my final function for conversion
> of DMS to DD:
> (if this is incorrect, please tell me)
>
> ;========================================================================
> function dms2dd(dms:string)
> ;========================================================================
>
> local dms_str, degrees, MINUTES, minutes, dd, cminutes
>
> begin
>
>    dms_str  = str_strip(dms)
>    degrees  = totype(str_get_field(dms_str, 1, "."), "float")
>    cminutes = tochar(str_get_field(dms_str, 2,"."))
>    minutes  = totype(tostring(cminutes(0:1)), "float")  ; 2 places only!
>
>    if (any(minutes.ge.60)) then
>        print("dms2dd: illegal minutes value >= 60")
>        exit
>    end if
>
>    dd = abs(degrees) + (abs(minutes)/60.0)
>    if (any(tofloat(degrees).le.0.0)) then    ; degrees in western or
> southern hemisphere
>      dd = dd*(-1.0)
>    end if
>
>    return(dd)
>
> end
> ;========================================================================
>
>
> Am 24.01.2019 um 21:12 schrieb Dennis Shea:
>
>
> Well, of course, NCL [other languages also] would treat the following as
> 'real' numbers
> ===
>
> undef ("dm_to_deg")
> function dm_to_deg(DM:numeric)
> ;  DM: latitude or longitude: structure: mantissa.characteristic
> ;      Example: 54.41:  degrees.minute: mantissa=51,  characteristic=41
> local delim, dm_str, mantissa, CHARACTERISTIC, characteristic, deg
>
> begin
>    delim  = "."
>    dm_str = tostring(DM)
>    mantissa       = totype(str_get_field(dm_str, 1, delim), typeof(DM))
>    CHARACTERISTIC = tochar(str_get_field(dm_str, 2, delim))
>    characteristic = totype(tostring(CHARACTERISTIC(0:1)),typeof(DM))  ; 2
> places
>    if (any(characteristic.ge.60)) then
>        print("dm_to_deg: illegal characteristic value >= 60")
>        exit
>    end if
>    deg = mantissa + (characteristic/60.0)
>    deg at long_name = "degree coordinates"
>    deg at NCL_tag    = "dm_to_deg"
>    deg at info       = "global locations in degrees: derived from dm"
>    return(deg)
> end
> ;========================================================================
> ;                       MAIN: dms ==> degrees_minute_second
> ;========================================================================
>
>   lat_dm  = 54.41                 ; not 'real' number, rather  (54° 41')
>   lat_deg = dm_to_deg(lat_dm)
>   print(lat_deg)
>   print("")
>   print("===============")
>   print("")
>   lon_dm  = 13.26                  ; not 'real' number, rather    (13° 26')
>   lon_deg = dm_to_deg(lon_dm)
>
>
> On Thu, Jan 24, 2019 at 9:54 AM MeteoBB <info at meteo-bb.de> wrote:
>
>> Hello,
>>
>> i have station data with lat/lon-coordinates in DMS (degree, minutes).
>> I suppose NCL/NCAR always want's decimal coordinates as input? That's why
>> my plotted data points appears at a wrong position.
>>
>> Example (this is my data looks like):
>> lat = 54.41 (54° 41')
>> lon = 13.26 (13° 26')
>>
>> I think I have to transform the coordinates from DMS to decimal, to have:
>> lat = 54.68
>> lon = 13.43
>>
>> Then the location will be placed correctly on map.
>>
>> My question:
>> Just wondering - is there really no built-in procedure/function for the
>> conversion from DMS to decimal coordinates? I found nothing about these
>> stuff in the mailing lists or on the web.
>> Furthermore, I am irritated that the tick labels are DMS in my example
>> program (see at the end), but he expects decimal coordinates.
>> If there is no built-in function, has anyone a funtion to convert DMS to
>> decimal or a workaround?
>>
>> Thanks a lot.
>>
>> Regards,
>> Robert
>>
>>
>> begin
>>
>>   wks  = gsn_open_wks ("png","test")
>>   res                        = True
>>   res at gsnMaximize            = True
>>   res at gsnFrame               = False
>>   res at mpGridAndLimbOn        = True
>>   res at pmTickMarkDisplayMode  = "Always"
>>   res at mpMinLatF              = 54
>>   res at mpMaxLatF              = 55
>>   res at mpMinLonF              = 13
>>   res at mpMaxLonF              = 14
>>
>>   res at mpGridSpacingF         = 0.25
>>   res at mpGridLineThicknessF   = 2.0
>>   res at mpGridLineColor        = "Gray30"
>>   res at mpOutlineBoundarySets  = "AllBoundaries"
>>   res at mpDataBaseVersion      = "MediumRes"
>>   res at mpDataSetName          = "Earth..4"
>>   res at mpGridAndLimbOn        = True
>>
>>   mkres                      = True
>>   mkres at gsMarkerIndex        = 16     ; Filled circle
>>   mkres at gsMarkerSizeF        = 0.008
>>
>>   plot   = gsn_csm_map(wks,res)
>>   gsn_polymarker(wks,plot,13.26,54.41,mkres)
>>   frame(wks)
>>
>> end
>>
>>
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>
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