question re: projections

Hello All,

I wanted to confirm my understanding of how IDV 1.2b1 handles map projections and ask a couple of related questions.

1) an IDV "projection" combines the map projection with maximum spatial extent ("Default Zoom"). This is a spatial clip of the data and not actually a limit on the minimum scale.

2) the Default Zoom cannot be edited via the Projection Manager and can only be edited manually in the $HOME/.metapps/DefaultIdv/projections.xml. There is no import facility to bring in an externally-created projection definition.

3) only 4 map projections: Geographic (unprojected), Lambert Conformal Conic, Transverse Mercator, and Stereographic are supported.

4) When the "Reset Projection With New Data" option is selected, the display is set to the geographic extent of the last dataset added and all previously added datasets are not only clipped/zoomed in, but reprojected to the current map projection. If this option is not selected, datasets using different projections are overlaid without re-projecting the data.

Can someone please correct or confirm these assumptions?

Also, can someone point me to the facility for programatically adding/editing Saved Projections as an alternative to using the GUI Projection Manager?

Is there a way to get information about the current projection? For example "Reset projection with new data" is true, one adds a new datasource/display, and the projection is changed. How can I find the parameters of this new projection?

Thanks so much for the help!

-- john