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MAP_SET vs MAP_PROJ_* [message #41671]

Wed, 10 November 2004 08:09

KM
Messages: 29
Registered: October 2004

Junior Member

In a different thread, I mentioned MAP_SET, and David Fanning wrote:

> Well, the MAP_PROJ_*** routines are quite good and can be used
> with either direct or object graphics. And of course you get a
> much more complete set of map projections and options when you use
> them.

I hadn't know about the MAP_PROJ_* routines, as I haven't used IDL
since 5.6 when they were introduced.

I don't need the extra projections, nor the fine-grained detail of
the major/minor planet axes, etc.

Can anyone recommend one over the other? Is there a speed
difference?

Also, this is an educational product, and it would be great for the
kids to be able to print & make globes out of their maps. Here are
some possibilities:
http://www.progonos.com/furuti/MapProj/Normal/ProjPoly/Foldo ut/foldout.html

Has anyone added map projections to the IDL routines and can offer
advice? I am comfortable modifying the routines, and in the past
have added magnetically-aligned continents as an option to
MAP_CONTINENTS.

Thanks,

-k.

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Re: MAP_SET vs MAP_PROJ_* [message #42459 is a reply to message #41671]

Wed, 09 February 2005 21:15

Gadhavi
Messages: 5
Registered: February 2005

Junior Member

Ben Tupper wrote:
> Gadhavi wrote:
>> Dear Friends,
>> I tried to run the program given by Ben that is mapTest. I
found
>> that map_continent and map_grid subroutines are not accepting the
>> keyword map_structure. I am using IDL 5.6. The subroutine shown by
Ben
>> is very useful for my purpose. Any suggestion to overcome this
problem
>> Thanking you
>
> Hi ,
>
> Those routines did not accept the MAP_STRUCTURE until IDL 6.1. Your
alternative
> is to set all of the paramters with the tradtional MAP_SET procedure.
>
> Ben

Thank you Ben
I have IDL version 5.6. I have to use GCTP routine which are available
through only MAP_PROJ_INIT function. I also tried to modify !MAP system
variable by assigning it to the results returned by MAP_PROJ_INIT
function but I could not get the work done. Let me tell more details
about the work I want to do. I have MODIS satellite data for land
reflectance. Which are available on the grid of size 1200 x 1200 on
Integerized Sinusoidal projection. Latitudes and Longitudes for four
corner points are also given. I can create the image of the size say
400 x 400 from given data using rebin. This image I want to project
over map with political bounderies and rivers. First of all Integerized
sinusoidal projection is not available in MAP_SET. So I have to use
MAP_PROJ_INIT function. It appears to me that this function do not
accept keyword "limit" with 8 elements giving 4 corner latitudes and
longitudes. Rather it accepts limit keyword with diagonal values of
latitude and longitude. This may not be correct for my problem as given
image is not rectangular in terms of latitude and longitude. This is
one part of my problem. Another problem is that I want to extract the
data values for station with known latitude and longitude. For that
purpose I want to calculate nearest index number to that station. I
will highly appreciate the help in this regard
Thanking you
HG

HG

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Re: MAP_SET vs MAP_PROJ_* [message #42494 is a reply to message #41671]

Tue, 08 February 2005 10:01

btt
Messages: 345
Registered: December 2000

Senior Member

Gadhavi wrote:
> Dear Friends,
> I tried to run the program given by Ben that is mapTest. I found
> that map_continent and map_grid subroutines are not accepting the
> keyword map_structure. I am using IDL 5.6. The subroutine shown by Ben
> is very useful for my purpose. Any suggestion to overcome this problem
> Thanking you

Hi ,

Those routines did not accept the MAP_STRUCTURE until IDL 6.1. Your alternative
is to set all of the paramters with the tradtional MAP_SET procedure.

Ben

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Re: MAP_SET vs MAP_PROJ_* [message #42553 is a reply to message #41671]

Wed, 16 February 2005 14:15

KM
Messages: 29
Registered: October 2004

Junior Member

On Wed, 16 Feb 2005, Gadhavi wrote:
> I am looking for a way to change the map projection for the data
> given in one projection. It seems that it is straight forward job
> with Map_proj_image routine but unfortunately I am still using
> older version of IDL (5.6) in which this routine is not available.
> I will highly appreciate it if some one can show way out from the
> problem I have mentioned in my earlier message. Even reference to
> the similar post will do.

Hi Gadhavi,

I've noticed the silent non-replies to your questions. This
newsgroup is usually very helpful, so I think maybe you cannot do
what you want easily. I can think of a few options:

1) Take the MAP_PROJ_* routines from an IDL 6.1 install and get them
working in 5.6. Maybe this just involves compiling them, maybe it is
impossible.

2) Upgrade to 6.0 or 6.1 or whatever version supports your routines
Note that if you just need to convert 1 file 1 time or something
like that, maybe you could do all the required work in < 7 minutes.
If this is the case, you can do it with the free demo/trial version.
I think writing to files is disabled, but print your data to screen,
then cut and paste.

3) Find the equations to convert from your current projection
(Integerized Sinusoidal projection?), and then hand-code a reverse
lookup, or hand-code a conversion from that to a projection that is
easier to deal with (Cylindrical/Equirectangular).

4) Find a different piece of software to solve your problem. If you
want/need to use IDL for other parts, then do suggestion 3 with
different software, then continue in IDL.

Good luck,

-k.
http://spacebit.dyndns.org/

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Re: MAP_SET vs MAP_PROJ_* [message #42569 is a reply to message #42459]

Wed, 16 February 2005 08:02

Gadhavi
Messages: 5
Registered: February 2005

Junior Member

Hello! Friends,
I am looking for a way to change the map projection for the data
given in one projection. It seems that it is straight forward job with
Map_proj_image routine but unfortunately I am still using older version
of IDL (5.6) in which this routine is not available. I will highly
appreciate it if some one can show way out from the problem I have
mentioned in my earlier message. Even reference to the similar post
will do.
Thanking you in anticipation

Harish Gadhavi

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Re: MAP_SET vs MAP_PROJ_* [message #42612 is a reply to message #42553]

Thu, 17 February 2005 10:18

savoie
Messages: 68
Registered: September 1996

Member

Ken Mankoff <mankoff@yahoo.com> writes:

> On Wed, 16 Feb 2005, Gadhavi wrote:
>> I am looking for a way to change the map projection
>> <snip>

> I've noticed the silent non-replies to your questions. This newsgroup is
> usually very helpful, so I think maybe you cannot do what you want easily. I
> can think of a few options:
>
> 4) Find a different piece of software to solve your problem. If you want/need
> to use IDL for other parts, then do suggestion 3 with different software,
> then continue in IDL.

I can think of two tools that might be useful.

The MODIS Reprojection Tool:

http://edcdaac.usgs.gov/landdaac/tools/modis/about.asp

And possibly:

The MODIS Swath-to-Grid Toolbox (MS2GT) is a set of software tools that can
be used to read HDF-EOS files containing MODIS swath data and produce flat
binary files containing gridded data in a variety of map
projections. Multiple input files corresponding to successively acquired 5
minute MODIS "scenes" can be processed together to produce a seamless output
grid.

http://nsidc.org/PROJECTS/HDFEOS/MS2GT/

Good luck.

Matt

--
Matthew Savoie - Scientific Programmer
National Snow and Ice Data Center
(303) 735-0785 http://nsidc.org

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