[Octave-bug-tracker] [bug #47502] geometry or mapping package: polysplit and polyjoin functions

[Philip Nienhuis]

Follow-up Comment #3, bug #47502 (project octave):

Looking at the description of the files I am not very sure if the geometry
package is the right place.
AFAICS these functions are mainly used for converting (X,Y) or (Lat, Lon)
coordinates in mapstructs or geostructs to a form in which they can more
easily be plotted, and back.  So they may be more useful in the mapping
package after all.  Sorry for a bit of confusion.

JuanPi, what is your opinion? Does the geometry package use the cell array
coordinate format?

@Alex:
=======
Thanks for your contribution.

Contributions like this should go on the patch tracker, not bug tracker.

Looking at polyjoin.m I see a for loop that had better be vectorized to avoid
undue CPU time. 
shapedraw.m in the mapping package invokes a better construct, I just
translated it into 2D for you:

XY(1:2:2*numel (latcells), :) = [{latcells{:}}' , {loncells{:}}'];
XY(2:2:2*numel (latcells) - 1, :) = NaN;
XY = cell2mat (XY);
lat = XY(:, 1);
lon = XY(:, 2);


(BTW this trick is actually due to David Bateman)

The reverse operation in polysplit.m should also be amenable to vectorization.
I'll have a look at it if no one beats me to it.

Furthermore, would you please follow Octave coding style?

- "A ~= B" should be "A != B"

- "~iscell" => "! iscell"

- two consecutive "|" rather than one

- indent only two spaces instead of four

... and please adapt the texinfo header to mention that X and Y coordinates
can be treated as well. The Matlabs docs don't mention that but this is very
useful.

Similar goes to polysplit.m.


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