[gradsusr] convert world coordinate distance to real distance (km)
wendi harjupa
wendiharjupa at gmail.com
Mon Nov 7 19:42:07 EST 2016
Dear Mr Phil
Thank you very much for your explanation.
But the result is totally wrong.
The estimate result just about 5 km.
I think I need the formula for short distance, which is we have to consider
the earth is flat.
Best regards,
wendi
On Tue, Nov 8, 2016 at 1:24 AM, HARVEY, PHILIP O NH-03 USAF AFMC 412
OSS/OSW <philip.harvey.1 at us.af.mil> wrote:
> Wendi,
>
> The formula expects input in radians. You must first convert the input
> latitudes and longitudes from degrees to radians. For example, 34.5 * PI /
> 180 = 0.011294, etc. Then apply the formula using your example values.
> The result of the formula using 34.5 lat 135 lon and 35 lat 135.5 lon is
> 38.8276 nautical miles or 38.8276 NM * 1.852 = 71.90872 KM.
>
> Phil
>
>
>
> -----Original Message-----
> From: gradsusr-bounces at gradsusr.org [mailto:gradsusr-bounces at gradsusr.org]
> On Behalf Of Jeff Duda
> Sent: Saturday, November 05, 2016 7:34 AM
> To: GrADS Users Forum <gradsusr at gradsusr.org>
> Subject: Re: [gradsusr] convert world coordinate distance to real distance
> (km)
>
> Wendi,
> Keep in mind what happens when you alter the geographical bounds in the
> control file. Those XDEF/YDEF/ZDEF/TDEF lines control the bounds of your
> dimension environment when running grads. Now that you've set the xdef and
> ydef to start at 1 and increment by very small values, the maximum x and y
> values in your dimension environment are now
>
>
> max_x = 1 + 319*0.005483962 = 2.749
>
> max_y = 1 + 319*0.00452226 = 2.443
>
>
> Notice how this math is derived from your control file. This means the
> maximum values for lat and lon that won't result in an error are 2.749 and
> 2.443. You set lat and lon to well outside those ranges in your script,
> which is why you are getting the error. You can instead reset lat and lon
> so that they're within the bounds above, but I think that's getting away
> from the problem you're trying to solve. My understanding is that you want
> to plot a field using linear distance coordinates rather than geographical
> coordinates. If so, then you don't want to be using lat/lon to set your
> dimensions. Use 'set x' and 'set y', and also set your initial value in
> your XDEF and YDEF lines to zero so that the lower left corner of your
> plots will be at distance coordinate (0,0) and increasing as you go up and
> right. Is this what you wanted to do?
>
>
> Jeff Duda
>
>
> On Sat, Nov 5, 2016 at 1:35 AM, wendi harjupa <wendiharjupa at gmail.com
> <mailto:wendiharjupa at gmail.com> > wrote:
>
>
> Dear Mr. Jeff
>
> Thank you very much for your advice.
> I have tried it for several times, but it does not work.
> I am very sorry for asking you again.
>
> I got an error as below
> Data Request Warning: Request is completely outside file limits
> Cannot contour grid - all undefined values
> Error in xcbar.gs <http://xcbar.gs> : No shading information
>
>
> Here my ctl file and gs file
>
> try.ctl
>
> DSET /TAKAYASU/wendi/xband/G000.grads/KINKI/20150808_0900-
> 1700/data/KINKI00001-20150808-1400-G000-EL000000.bin
> UNDEF -999
> XDEF 319 LINEAR 1 0.005483962
> YDEF 319 LINEAR 1 0.00452226
> # ZDEF 81 LINEAR 125 250
> TDEF 120 LINEAR 09:00Z14JUL1500 60yr
> VARS 1
> rr 81 99 rainfall (mm)
> ENDVARS
>
>
> try.gs <http://try.gs>
>
> 'reinit'
> 'open /TAKAYASU/wendi/overlay_cappi/try.ctl'
> 'setXrain.gs'
> # 'set mproj off'
> # 'setCOMMON.gs'
> 'set lon 134.9 135.4'
> 'set lat 34 34.5'
> 'd rr'
> 'xcbar 8.6 8.8 0.8 4 -fw 0.11 -fh 0.15 -edge triangle -fstep 1
> -line on -lc 1'
> 'set strsiz 0.15 0.15'
> 'draw string 8.5 4.15 mm'
>
> # 'set xaxis 0 10 1'
> # 'set yaxis 0 10 1'
>
> 'close 1'
>
> Thank you very much.
> Best regards,
> wendi
>
>
>
>
>
>
>
> On Thu, Nov 3, 2016 at 1:37 AM, Jeff Duda <jeffduda319 at gmail.com
> <mailto:jeffduda319 at gmail.com> > wrote:
>
>
> Wendi,
>
> You can always change the text of any control file. There
> should not be anything stopping you from doing that. Please clarify what
> you mean.
>
>
> Jeff
>
>
> On Tue, Nov 1, 2016 at 11:53 PM, wendi harjupa <
> wendiharjupa at gmail.com <mailto:wendiharjupa at gmail.com> > wrote:
>
>
> Dear Mr Jeff
>
> Thank you very much for your help.
>
> I have two different types of data set and I need
> to make composite data with those data.
> One data is mismatch, then I need to know how far
> the mismatch.
>
> One of my data set is binary and another one is
> netCDF.
>
> I can change my control file in my binary data.
> But, I cannot do this for my netCDF data.
> Would you mind to suggest me, how to change XDEF
> and YDEF in netCDF data?
>
> Thank you very much
>
> best regards,
> wendi
>
> On Wed, Nov 2, 2016 at 12:02 AM, Jeff Duda <
> jeffduda319 at gmail.com <mailto:jeffduda319 at gmail.com> > wrote:
>
>
> Wendi,
>
> It sounds like you want to draw a plot
> with geographic coordinates replaced by straight-line/distance coordinates
> instead. If that is the case, one thing you can try is removing the PDEF
> line from your control file and resetting your XDEF and YDEF lines to start
> at 0 (but keep the delta value). That might work. If that doesn't work, you
> could also try turning off the map projection in grads (set mproj off) and
> then using 'set xaxis' and 'set yaxis' in clever ways to make it look like
> the map you draw is in terms of linear distance. Good luck.
>
>
> Jeff Duda
>
>
> On Tue, Nov 1, 2016 at 9:32 AM, HARVEY,
> PHILIP O NH-03 USAF AFMC 412 OSS/OSW <philip.harvey.1 at us.af.mil <mailto:
> philip.harvey.1 at us.af.mil> > wrote:
>
>
> See Ed Williams' Aviation
> Formulary at http://williams.best.vwh.net/avform.htm <
> http://williams.best.vwh.net/avform.htm> for great circle distance, etc
> formulas. The formula you desire is only requires 1 line and can easily be
> written into a function.
>
> Phil
>
>
>
> -----Original Message-----
> From:
> gradsusr-bounces at gradsusr.org <mailto:gradsusr-bounces at gradsusr.org>
> [mailto:gradsusr-bounces at gradsusr.org <mailto:gradsusr-bounces@
> gradsusr.org> ] On Behalf Of wendi harjupa
> Sent: Tuesday, November 01, 2016
> 2:01 AM
> To: GrADS Users Forum <
> gradsusr at gradsusr.org <mailto:gradsusr at gradsusr.org> >
> Subject: [gradsusr] convert world
> coordinate distance to real distance (km)
>
> Dear every one
>
> I have problem with converting
> distance in world coordinate to distance,
>
> I have map with
> lon = 135 135.5
> lat = 34.5 35
>
> I want to set lon =135, as 0 km,
> and lat=34.5 as 0 km.
> as we know that 1 deg is about 110
> km.
>
> Is there any function in grads
> that can directly convert the world coordinat distance to real distance
> (km)?
>
> Please, any help would be very
> appreciate.
>
> thank you
> regards,
> wendi
>
>
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>
>
>
> --
>
> Jeff Duda
> Post-doctoral research associate
> University of Oklahoma School of
> Meteorology
>
>
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> --
>
> Jeff Duda
> Post-doctoral research associate
> University of Oklahoma School of Meteorology
>
>
>
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>
>
> --
>
> Jeff Duda
> Post-doctoral research associate
> University of Oklahoma School of Meteorology
>
>
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