plotting plate boundaries with different colors

[sreejith km]

Hi..

Can anybody let me know how  to plot different plate boundaries like MOR, subduction zones  with different colors from  world plate boundary data as input. I am using Windows version of GMT.

 

With regards

 Sree

--
SREEJITH K M
Space Applications Centre 

Ahmedabad, India.

 

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[Joaquim Luis]

sreejith km wrote:
> Hi..
> Can anybody let me know how  to plot different plate boundaries like
> MOR, subduction zones  with different colors from  world plate boundary
> data as input. I am using Windows version of GMT.
>  

You mean, like this?

http://w3.ualg.pt/~jluis/mirone/images/datasets.jpg

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[sreejith km]

Dear Joaquim

Thanks for the reply

Yes, similar to the figure you have posted. I wanted to plot the Mid Oceanic Ridges and Andaman subduction zone in Indian ocean with different colors



sreejith

On Fri, Mar 13, 2009 at 1:06 AM, Joaquim Luis <jluis@...> wrote:

sreejith km wrote:

Hi..
Can anybody let me know how  to plot different plate boundaries like MOR, subduction zones  with different colors from  world plate boundary data as input. I am using Windows version of GMT.
 

You mean, like this?

http://w3.ualg.pt/~jluis/mirone/images/datasets.jpg

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SREEJITH K M
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[Peter Schmidt-3]

Hi all

I'm trying to understand the use of the -C[xoffset/yoffset] option in
combination with the -F[unit] option of mapproject, and especially when
the output/input units are not m (e.g. by the use of -Fk)

Trying the commands:
>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -F -C1.e5/1.e5
100000  100000

>>> echo " 100000  100000 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -F
-C1.e5/1.e5 -I
10      10

seems to be working nicely, however, using -Fk we run it turns out the
offsets to append to the -C option differs and the proper command and
its inverse are:
>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C1.e5/1.e5
100     100

>>> echo " 100  100 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
-C0.1/0.1 -I
10      10

i.e. -C1.e5/1.e5  vs. -C0.1/0.1, likewise:

>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C1.e4/1.e4
10      10

>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
-C0.01/0.01 -I
10      10

>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C1.e3/1.e3
1       1

>>> echo " 1  1 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
-C0.001/0.001 -I
10      10

Hence my question is simply whether this is really how the offsets  on
the -C option are intended to work

reg P



--
********************************************************************************
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PhD Student                    Mobile: [phone]
Dept. of Earth Sciences        e-mail: peter.schmidt@...
Geophysics                     http://www.geofys.uu.se/?q=view/home/75
Uppsala University
Villavagen 16
SE-75236 Uppsala
********************************************************************************

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[Joaquim Luis-2]

Peter,

This thing can be confusing and the best is to use SI units, that is meters
What happens is that the shifts in -C are applied the scale factor as
selected by -F.
See the following example

echo 1000 1000 | mapproject -Jt10/10/1:1 -R5/15/5/15 -F -C -I
10.0091211      10.0090408

--- Next will give the same because (x,y) will be subtracted by the
shift before transformation
echo 1100 1100 | mapproject -Jt10/10/1:1 -R5/15/5/15 -F -C100/100 -I
10.0091211      10.0090408

------------------------- Now in km ------------------------------------

echo 1 1 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C -I
10.0091211      10.0090408

---- One might think that we could also do it this way:
echo 1.1 1.1 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C0.1/0.1 -I
9.10034056      9.10471515

--- But no, this is the right way (1e-4 * 1000 = 0.1)
echo 1.1 1.1 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C1e-4/1e-4 -I
10.0091211      10.0090408


Joaquim Luis

> Hi all
>
> I'm trying to understand the use of the -C[xoffset/yoffset] option in
> combination with the -F[unit] option of mapproject, and especially when
> the output/input units are not m (e.g. by the use of -Fk)
>
> Trying the commands:
>  
>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -F -C1.e5/1.e5
>>>>        
> 100000  100000
>
>  
>>>> echo " 100000  100000 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -F
>>>>        
> -C1.e5/1.e5 -I
> 10      10
>
> seems to be working nicely, however, using -Fk we run it turns out the
> offsets to append to the -C option differs and the proper command and
> its inverse are:
>  
>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C1.e5/1.e5
>>>>        
> 100     100
>
>  
>>>> echo " 100  100 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>        
> -C0.1/0.1 -I
> 10      10
>
> i.e. -C1.e5/1.e5  vs. -C0.1/0.1, likewise:
>
>  
>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C1.e4/1.e4
>>>>        
> 10      10
>
>  
>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>        
> -C0.01/0.01 -I
> 10      10
>
>  
>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C1.e3/1.e3
>>>>        
> 1       1
>
>  
>>>> echo " 1  1 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>        
> -C0.001/0.001 -I
> 10      10
>
> Hence my question is simply whether this is really how the offsets  on
> the -C option are intended to work
>
> reg P
>
>
>
>  

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[Peter Schmidt-3]

Hmmm

I think what confuses me the most is that when you do the forward
transformation the offset should be specified in m if the -F option is
used, e.g.

echo 10.0091211 10.0090408 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
-C100/100
1.1     1.1

Whilst when employing the inverse transformation this no longer holds,
instead the offset to specify should be specified as magnitude of offset
of the xy coordinates divided by the unit i.e. an offset of magnitude
0.1 in the xy coordinates and units of km (1000) yields an offset on the
C option of 0.1/1000 = 1.e-4

echo 1.1 1.1 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C1e-4/1e-4 -I
10.0091211      10.0090408


I would be nice if this were mentioned in the manpage (mabe it is but I
can't find it), even nicer it would be if this was handled internally
(i.e. same offsets can be used for both forward and inverse
transformation). But these are mere wishes, now that I know how to
handle the the offsets I donot need them.

Thanks Peter S



J Luis wrote:

> Peter,
>
> This thing can be confusing and the best is to use SI units, that is
> meters
> What happens is that the shifts in -C are applied the scale factor as
> selected by -F.
> See the following example
>
> echo 1000 1000 | mapproject -Jt10/10/1:1 -R5/15/5/15 -F -C -I
> 10.0091211      10.0090408
>
> --- Next will give the same because (x,y) will be subtracted by the
> shift before transformation
> echo 1100 1100 | mapproject -Jt10/10/1:1 -R5/15/5/15 -F -C100/100 -I
> 10.0091211      10.0090408
>
> ------------------------- Now in km ------------------------------------
>
> echo 1 1 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C -I
> 10.0091211      10.0090408
>
> ---- One might think that we could also do it this way:
> echo 1.1 1.1 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C0.1/0.1 -I
> 9.10034056      9.10471515
>
> --- But no, this is the right way (1e-4 * 1000 = 0.1)
> echo 1.1 1.1 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C1e-4/1e-4 -I
> 10.0091211      10.0090408
>
>
> Joaquim Luis
>
>
>
>> Hi all
>>
>> I'm trying to understand the use of the -C[xoffset/yoffset] option in
>> combination with the -F[unit] option of mapproject, and especially when
>> the output/input units are not m (e.g. by the use of -Fk)
>>
>> Trying the commands:
>>  
>>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -F
>>>>> -C1.e5/1.e5
>>>>>        
>> 100000  100000
>>
>>  
>>>>> echo " 100000  100000 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -F
>>>>>        
>> -C1.e5/1.e5 -I
>> 10      10
>>
>> seems to be working nicely, however, using -Fk we run it turns out the
>> offsets to append to the -C option differs and the proper command and
>> its inverse are:
>>  
>>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>> -C1.e5/1.e5
>>>>>        
>> 100     100
>>
>>  
>>>>> echo " 100  100 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>>        
>> -C0.1/0.1 -I
>> 10      10
>>
>> i.e. -C1.e5/1.e5  vs. -C0.1/0.1, likewise:
>>
>>  
>>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>> -C1.e4/1.e4
>>>>>        
>> 10      10
>>
>>  
>>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>>        
>> -C0.01/0.01 -I
>> 10      10
>>
>>  
>>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>> -C1.e3/1.e3
>>>>>        
>> 1       1
>>
>>  
>>>>> echo " 1  1 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>>        
>> -C0.001/0.001 -I
>> 10      10
>>
>> Hence my question is simply whether this is really how the offsets  on
>> the -C option are intended to work
>>
>> reg P
>>
>>
>>
>>  
>
> To unsubscribe, send the message "signoff gmt-help" to
> listserv@...
>

--
********************************************************************************
Peter Schmidt                     Tel: [phone]
PhD Student                    Mobile: [phone]
Dept. of Earth Sciences        e-mail: peter.schmidt@...
Geophysics                     http://www.geofys.uu.se/?q=view/home/75
Uppsala University
Villavagen 16
SE-75236 Uppsala
********************************************************************************

To unsubscribe, send the message "signoff gmt-help" to listserv@...

[Joaquim Luis]

Both behaviors are consistent when one knows that the shifts are
multiplied by the scale factor
determined by -F<unit> BEFORE the transformation is applied.
 I agree that this is confusing and possibly was not designed on purpose.
It would be simpler if the shifts were not touched and left to user
responsibility to give the right
values. After all, they are part of the input data. But maybe I'm
overlooking something.
Paul?

> Hmmm
>
> I think what confuses me the most is that when you do the forward
> transformation the offset should be specified in m if the -F option is
> used, e.g.
>
> echo 10.0091211 10.0090408 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
> -C100/100
> 1.1     1.1
>
> Whilst when employing the inverse transformation this no longer holds,
> instead the offset to specify should be specified as magnitude of offset
> of the xy coordinates divided by the unit i.e. an offset of magnitude
> 0.1 in the xy coordinates and units of km (1000) yields an offset on the
> C option of 0.1/1000 = 1.e-4
>
> echo 1.1 1.1 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C1e-4/1e-4 -I
> 10.0091211      10.0090408
>
>
> I would be nice if this were mentioned in the manpage (mabe it is but I
> can't find it), even nicer it would be if this was handled internally
> (i.e. same offsets can be used for both forward and inverse
> transformation). But these are mere wishes, now that I know how to
> handle the the offsets I donot need them.
>
> Thanks Peter S
>
>
>
> J Luis wrote:
>  
>> Peter,
>>
>> This thing can be confusing and the best is to use SI units, that is
>> meters
>> What happens is that the shifts in -C are applied the scale factor as
>> selected by -F.
>> See the following example
>>
>> echo 1000 1000 | mapproject -Jt10/10/1:1 -R5/15/5/15 -F -C -I
>> 10.0091211      10.0090408
>>
>> --- Next will give the same because (x,y) will be subtracted by the
>> shift before transformation
>> echo 1100 1100 | mapproject -Jt10/10/1:1 -R5/15/5/15 -F -C100/100 -I
>> 10.0091211      10.0090408
>>
>> ------------------------- Now in km ------------------------------------
>>
>> echo 1 1 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C -I
>> 10.0091211      10.0090408
>>
>> ---- One might think that we could also do it this way:
>> echo 1.1 1.1 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C0.1/0.1 -I
>> 9.10034056      9.10471515
>>
>> --- But no, this is the right way (1e-4 * 1000 = 0.1)
>> echo 1.1 1.1 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C1e-4/1e-4 -I
>> 10.0091211      10.0090408
>>
>>
>> Joaquim Luis
>>
>>
>>
>>    
>>> Hi all
>>>
>>> I'm trying to understand the use of the -C[xoffset/yoffset] option in
>>> combination with the -F[unit] option of mapproject, and especially when
>>> the output/input units are not m (e.g. by the use of -Fk)
>>>
>>> Trying the commands:
>>>  
>>>      
>>>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -F
>>>>>> -C1.e5/1.e5
>>>>>>        
>>>>>>            
>>> 100000  100000
>>>
>>>  
>>>      
>>>>>> echo " 100000  100000 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -F
>>>>>>        
>>>>>>            
>>> -C1.e5/1.e5 -I
>>> 10      10
>>>
>>> seems to be working nicely, however, using -Fk we run it turns out the
>>> offsets to append to the -C option differs and the proper command and
>>> its inverse are:
>>>  
>>>      
>>>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>>> -C1.e5/1.e5
>>>>>>        
>>>>>>            
>>> 100     100
>>>
>>>  
>>>      
>>>>>> echo " 100  100 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>>>        
>>>>>>            
>>> -C0.1/0.1 -I
>>> 10      10
>>>
>>> i.e. -C1.e5/1.e5  vs. -C0.1/0.1, likewise:
>>>
>>>  
>>>      
>>>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>>> -C1.e4/1.e4
>>>>>>        
>>>>>>            
>>> 10      10
>>>
>>>  
>>>      
>>>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>>>        
>>>>>>            
>>> -C0.01/0.01 -I
>>> 10      10
>>>
>>>  
>>>      
>>>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>>> -C1.e3/1.e3
>>>>>>        
>>>>>>            
>>> 1       1
>>>
>>>  
>>>      
>>>>>> echo " 1  1 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>>>        
>>>>>>            
>>> -C0.001/0.001 -I
>>> 10      10
>>>
>>> Hence my question is simply whether this is really how the offsets  on
>>> the -C option are intended to work
>>>
>>> reg P
>>>
>>>
>>>
>>>  
>>>      
>> To unsubscribe, send the message "signoff gmt-help" to
>> listserv@...
>>
>>    
>
>
>  

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[Peter Schmidt-3]

Yes in a sense I agree, the shift should probably be left to the user,
but as the user (in this case me) might be very lazy  :-) it is very
nice to have mapproject taking care of it once (s)he knows how to do so

RegP

Joaquim Luis wrote:

> Both behaviors are consistent when one knows that the shifts are
> multiplied by the scale factor
> determined by -F<unit> BEFORE the transformation is applied.
> I agree that this is confusing and possibly was not designed on purpose.
> It would be simpler if the shifts were not touched and left to user
> responsibility to give the right
> values. After all, they are part of the input data. But maybe I'm
> overlooking something.
> Paul?
>
>
>> Hmmm
>>
>> I think what confuses me the most is that when you do the forward
>> transformation the offset should be specified in m if the -F option is
>> used, e.g.
>>
>> echo 10.0091211 10.0090408 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>> -C100/100
>> 1.1     1.1
>>
>> Whilst when employing the inverse transformation this no longer holds,
>> instead the offset to specify should be specified as magnitude of offset
>> of the xy coordinates divided by the unit i.e. an offset of magnitude
>> 0.1 in the xy coordinates and units of km (1000) yields an offset on the
>> C option of 0.1/1000 = 1.e-4
>>
>> echo 1.1 1.1 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C1e-4/1e-4 -I
>> 10.0091211      10.0090408
>>
>>
>> I would be nice if this were mentioned in the manpage (mabe it is but I
>> can't find it), even nicer it would be if this was handled internally
>> (i.e. same offsets can be used for both forward and inverse
>> transformation). But these are mere wishes, now that I know how to
>> handle the the offsets I donot need them.
>>
>> Thanks Peter S
>>
>>
>>
>> J Luis wrote:
>>  
>>> Peter,
>>>
>>> This thing can be confusing and the best is to use SI units, that is
>>> meters
>>> What happens is that the shifts in -C are applied the scale factor as
>>> selected by -F.
>>> See the following example
>>>
>>> echo 1000 1000 | mapproject -Jt10/10/1:1 -R5/15/5/15 -F -C -I
>>> 10.0091211      10.0090408
>>>
>>> --- Next will give the same because (x,y) will be subtracted by the
>>> shift before transformation
>>> echo 1100 1100 | mapproject -Jt10/10/1:1 -R5/15/5/15 -F -C100/100 -I
>>> 10.0091211      10.0090408
>>>
>>> ------------------------- Now in km
>>> ------------------------------------
>>>
>>> echo 1 1 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C -I
>>> 10.0091211      10.0090408
>>>
>>> ---- One might think that we could also do it this way:
>>> echo 1.1 1.1 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C0.1/0.1 -I
>>> 9.10034056      9.10471515
>>>
>>> --- But no, this is the right way (1e-4 * 1000 = 0.1)
>>> echo 1.1 1.1 | mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk -C1e-4/1e-4 -I
>>> 10.0091211      10.0090408
>>>
>>>
>>> Joaquim Luis
>>>
>>>
>>>
>>>    
>>>> Hi all
>>>>
>>>> I'm trying to understand the use of the -C[xoffset/yoffset] option in
>>>> combination with the -F[unit] option of mapproject, and especially
>>>> when
>>>> the output/input units are not m (e.g. by the use of -Fk)
>>>>
>>>> Trying the commands:
>>>>  
>>>>      
>>>>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -F
>>>>>>> -C1.e5/1.e5
>>>>>>>                    
>>>> 100000  100000
>>>>
>>>>  
>>>>      
>>>>>>> echo " 100000  100000 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -F
>>>>>>>                    
>>>> -C1.e5/1.e5 -I
>>>> 10      10
>>>>
>>>> seems to be working nicely, however, using -Fk we run it turns out the
>>>> offsets to append to the -C option differs and the proper command and
>>>> its inverse are:
>>>>  
>>>>      
>>>>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>>>> -C1.e5/1.e5
>>>>>>>                    
>>>> 100     100
>>>>
>>>>  
>>>>      
>>>>>>> echo " 100  100 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>>>>                    
>>>> -C0.1/0.1 -I
>>>> 10      10
>>>>
>>>> i.e. -C1.e5/1.e5  vs. -C0.1/0.1, likewise:
>>>>
>>>>  
>>>>      
>>>>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>>>> -C1.e4/1.e4
>>>>>>>                    
>>>> 10      10
>>>>
>>>>  
>>>>      
>>>>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>>>>                    
>>>> -C0.01/0.01 -I
>>>> 10      10
>>>>
>>>>  
>>>>      
>>>>>>> echo " 10  10 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>>>> -C1.e3/1.e3
>>>>>>>                    
>>>> 1       1
>>>>
>>>>  
>>>>      
>>>>>>> echo " 1  1 "  |   mapproject -Jt10/10/1:1 -R5/15/5/15 -Fk
>>>>>>>                    
>>>> -C0.001/0.001 -I
>>>> 10      10
>>>>
>>>> Hence my question is simply whether this is really how the offsets  on
>>>> the -C option are intended to work
>>>>
>>>> reg P
>>>>
>>>>
>>>>
>>>>        
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>>>
>>>    
>>
>>
>>  
>
> To unsubscribe, send the message "signoff gmt-help" to
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Peter Schmidt                     Tel: [phone]
PhD Student                    Mobile: [phone]
Dept. of Earth Sciences        e-mail: peter.schmidt@...
Geophysics                     http://www.geofys.uu.se/?q=view/home/75
Uppsala University
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SE-75236 Uppsala
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[Peter Schmidt-3]

Hi again

I have some additional questions regarding mapproject, this time related
to the use of the -R option. As far as I have understood it the -R
option should really not affect the transformation (am I wrong here?)
but only what points are being transformed (and output) given that the
-S option is used. If the -S option is not used the -R option should not
affect the transformation I guess. However

echo 20 20 | mapproject -Jt10/10/1:1 -R0/1/0/1  -C
1.05059e+08     1.13809e+08

echo 20 20 | mapproject -Jt10/10/1:1 -R20/21/20/21  -C
1.04922e+08     1.12897e+08

So I guess I'm missing out on some important point here and any pointer
is apreciated (well, the difference is small, but...).

regards Peter S

--
********************************************************************************
Peter Schmidt                     Tel: [phone]
PhD Student                    Mobile: [phone]
Dept. of Earth Sciences        e-mail: peter.schmidt@...
Geophysics                     http://www.geofys.uu.se/?q=view/home/75
Uppsala University
Villavagen 16
SE-75236 Uppsala
********************************************************************************

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[Marta Ghidella]

Hello Peter:

I think it is one of the cases described under "restrictions" on the manual
page:

"Transverse Mercator (-JT) and UTM (-JU) will will use the spherical
solution when either the west or east boundary given in -R is more than 10
degrees from the central meridian"'

This is what happens to your second example.

Please check.

Cheers,

Marta

----- Original Message -----
From: "Peter Schmidt" <peter.schmidt@...>
To: <GMT-HELP@...>
Sent: Tuesday, November 10, 2009 4:30 AM
Subject: [GMT-HELP] Some more mapproject questions ( -R option)


Hi again

I have some additional questions regarding mapproject, this time related
to the use of the -R option. As far as I have understood it the -R
option should really not affect the transformation (am I wrong here?)
but only what points are being transformed (and output) given that the
-S option is used. If the -S option is not used the -R option should not
affect the transformation I guess. However

echo 20 20 | mapproject -Jt10/10/1:1 -R0/1/0/1  -C
1.05059e+08     1.13809e+08

echo 20 20 | mapproject -Jt10/10/1:1 -R20/21/20/21  -C
1.04922e+08     1.12897e+08

So I guess I'm missing out on some important point here and any pointer
is apreciated (well, the difference is small, but...).

regards Peter S

--
********************************************************************************
Peter Schmidt                     Tel: [phone]
PhD Student                    Mobile: [phone]
Dept. of Earth Sciences        e-mail: peter.schmidt@...
Geophysics                     http://www.geofys.uu.se/?q=view/home/75
Uppsala University
Villavagen 16
SE-75236 Uppsala
********************************************************************************

To unsubscribe, send the message "signoff gmt-help" to listserv@...

To unsubscribe, send the message "signoff gmt-help" to listserv@...

[Peter Schmidt-3]

Wooops, didn't read that far down on the man page (feel a bit embarrased
now), thanks for the pointer

regP

Marta Ghidella wrote:

> Hello Peter:
>
> I think it is one of the cases described under "restrictions" on the manual
> page:
>
> "Transverse Mercator (-JT) and UTM (-JU) will will use the spherical
> solution when either the west or east boundary given in -R is more than 10
> degrees from the central meridian"'
>
> This is what happens to your second example.
>
> Please check.
>
> Cheers,
>
> Marta
>
> ----- Original Message -----
> From: "Peter Schmidt" <peter.schmidt@...>
> To: <GMT-HELP@...>
> Sent: Tuesday, November 10, 2009 4:30 AM
> Subject: [GMT-HELP] Some more mapproject questions ( -R option)
>
>
> Hi again
>
> I have some additional questions regarding mapproject, this time related
> to the use of the -R option. As far as I have understood it the -R
> option should really not affect the transformation (am I wrong here?)
> but only what points are being transformed (and output) given that the
> -S option is used. If the -S option is not used the -R option should not
> affect the transformation I guess. However
>
> echo 20 20 | mapproject -Jt10/10/1:1 -R0/1/0/1  -C
> 1.05059e+08     1.13809e+08
>
> echo 20 20 | mapproject -Jt10/10/1:1 -R20/21/20/21  -C
> 1.04922e+08     1.12897e+08
>
> So I guess I'm missing out on some important point here and any pointer
> is apreciated (well, the difference is small, but...).
>
> regards Peter S
>
>  

--
********************************************************************************
Peter Schmidt                     Tel: [phone]
PhD Student                    Mobile: [phone]
Dept. of Earth Sciences        e-mail: peter.schmidt@...
Geophysics                     http://www.geofys.uu.se/?q=view/home/75
Uppsala University
Villavagen 16
SE-75236 Uppsala
********************************************************************************

To unsubscribe, send the message "signoff gmt-help" to listserv@...