Preserving coordinate transformation [message #50823] |
Tue, 17 October 2006 03:47 |
Sverre Solberg
Messages: 18 Registered: February 2005
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Junior Member |
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I plot a map (by the MAP_SET etc routines) inside a widget_draw area
using "/button_events". When the user is clicking on the map the
program use the event (x and y) and the "convert_coord" to compute the
geographical coordinates of the position. However, when making other
plots in between, opening other draw widgets, the built-in coordinate
transformations (device->data) changes and destroys the conversion to
geo. coord. next time this window is clicked on. How could I store the
coordinate transformation? If it was a simple 2D plot, without the map,
I could just save the !x and !y variables and compute the conversion
myself, but that dont work when there's a map projection. I then need
to know how idl converts from device coordinates (returned by widget
draw) to map coordinates (lat/long) and I havent been able to find out
that. Any hints?
Sverre
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