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Re: Map Projections and Contour Plots. [message #15858 is a reply to message #15827]

Tue, 15 June 1999 00:00

Grady Daub
Messages: 22
Registered: June 1999

Junior Member

Martin Schultz wrote:

> LONs and LATs have to be monotonically increasing for a contour plot.
> Default is -180 to 180 for a global map, but if you want to center your
> map say on the Pacific, you need to "convert" your longitude coordinates
> to e.g. 0 to 360. You can try my convert_lon program (attached) for
> this. It is called as
> convert_lon,lon [,/ATLANTIC] [,/PACIFIC]
> and makes sure you get longitudes modulo 360.
>

Your convert_lon program was not attached.

Would your program make my non-monotonic lat,lon,data arrays in a form expected by CONTOUR ?

I've tried TRIANGULATE and TRIGRID and SPH_SCAT (the latter exactly as shown on dfanning.com, except with my own data)
and the results are weird. Is SPH_SCAT, when applied to data with max/min of around 200/-200, supposed to produce
output past 50000? That's the weird part.

TRIANGULATE and TRIGRID just don't like me. :-(
What's the deal with FVALUE?

> Finally (to complete the most prominent issues with contours on maps),
> if you plan to plot filled contours, there are occasions when you need
> the /CELL_FILL keyword *AND* CONTOUR will use the first fill color for
> values ABOVE your first threshold, i.e. you should add a very low number
> to your C_LEVEL specification if you have one.

Where is /CELL_FILL documented? It's not it the index and I've not found it anywhere near the CONTOUR section.

-Grady Daub

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[Message index]

		Map Projections and Contour Plots. By: Grady Daub on Thu, 10 June 1999 00:00
		Re: Map Projections and Contour Plots. By: Martin Schultz on Wed, 16 June 1999 00:00
		Re: Map Projections and Contour Plots. By: wmc on Wed, 16 June 1999 00:00
		Re: Map Projections and Contour Plots. By: Grady Daub on Tue, 15 June 1999 00:00
		Re: Map projections By: Liam E. Gumley on Mon, 12 November 2001 08:16

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