| UTM Mapping support [message #6894] |
Mon, 19 August 1996 00:00  |
Arno F. Granados
Messages: 8
Registered: August 1996
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Junior Member |
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I have a need for inputting UTM based data sets into IDL's mapping
utilities. The problem is that IDL does not directly support UTM
in it's map utilites. Does anyone have any routines for converting
from UTM to Lat/Lon and vica versa?
Arno Granados
Positive Systems Inc.
Leaders in Digital Aerial Photography
granados@possys.com
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| Re: UTM map [message #40265 is a reply to message #6894] |
Fri, 30 July 2004 01:16  |
sso
Messages: 13
Registered: February 2002
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Junior Member |
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Ben Tupper <btupper@bigelow.org> wrote in message news:<2mps37Fq1sctU1@uni-berlin.de>...
> Sverre Solberg wrote:
>> Is there any possibility to draw a rectangular grid (with typically
>> 30x40 grid cells in XxY direction) on a standard UTM map in idl? What
>> I'm looking for is a standard plot presenting numerical model results
>> with the grid cells coloured according to the values. The map itself
>> is easy enough to make but when overplotting squares with fixed
>> distance (in meters) the grid lines get "zig-zaged" when converted to
>> lat/lon. Do I e.g. have to split the grid lines into an extremely dens
>> row of UTM coordinates and then convert to lat/lon? A bit awkward. As
>> far as I know, idl hasn't any functionality for UTM map coordinates,
>> or am I wrong?
>>
>
> Hi,
>
> Starting with IDL 5.6, the handy MAP_PROJ_**** routines have made life a lot
> easier to deal with map coordinate conversions. These should help you with the
> forward and backward coordinate transformations. I'm not sure if this will help
> answer your question... which is ... well, what is your question again?
>
> Someday I'm gonna write a guide to mapping in IDL and throw in a nice GUI
> interface to the MAP_PROJ_INIT function. Just as soon as I figure it all out.
> Considering that I have frequently fussed with mapping in IDL for a long time
> and still have to start from scratch each time, it could be a while.
>
> Ben
Thanks. We are still using the 5.5 version so upgrading will be good
then. The problem which is now partly solved, was the following: I
have a rectangular UTM grid with a grid spacing of 5km in x- and
y-direction. I use your utm_to_ll routine to convert (each grid cell)
to geo. coordinates. However, when plotting this on top of the map
produced by the map_set,/trans routine the grid looks like it's
handdrawn with "bumpy" grid lines. I thought this was due to the
UTM->geo conversion but discovered that it was only seen on the screen
or if printed to a bitmap file. When making e.g. a cgm (or PS) file
the lines are perfectly straight. So this helps a lot, but still I'm
confused why the lines are not staight on the screen, and since this
is part of widget system with a clickable map, it's still a slight
problem.
Sverre
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| Re: UTM map [message #40291 is a reply to message #6894] |
Wed, 28 July 2004 07:41 |
btt
Messages: 345
Registered: December 2000
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Senior Member |
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Sverre Solberg wrote:
> Is there any possibility to draw a rectangular grid (with typically
> 30x40 grid cells in XxY direction) on a standard UTM map in idl? What
> I'm looking for is a standard plot presenting numerical model results
> with the grid cells coloured according to the values. The map itself
> is easy enough to make but when overplotting squares with fixed
> distance (in meters) the grid lines get "zig-zaged" when converted to
> lat/lon. Do I e.g. have to split the grid lines into an extremely dens
> row of UTM coordinates and then convert to lat/lon? A bit awkward. As
> far as I know, idl hasn't any functionality for UTM map coordinates,
> or am I wrong?
>
Hi,
Starting with IDL 5.6, the handy MAP_PROJ_**** routines have made life a lot
easier to deal with map coordinate conversions. These should help you with the
forward and backward coordinate transformations. I'm not sure if this will help
answer your question... which is ... well, what is your question again?
Someday I'm gonna write a guide to mapping in IDL and throw in a nice GUI
interface to the MAP_PROJ_INIT function. Just as soon as I figure it all out.
Considering that I have frequently fussed with mapping in IDL for a long time
and still have to start from scratch each time, it could be a while.
Ben
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