Hi, I often do this with ds9 and funtools. ds9 is an astronomy-oriented image viewer (http://hea-www.harvard.edu/RD/ds9/) but you can also use it with numpy array. Within ds9, you can define regions (ellipse, polynomial, etc) easily with a mouse. After you define a region (and save it as a file), you can convert it to a mask image with funtools (funtools is a name of an astronomy-oriented image utility pacakge). funtools only support fits file (image format in astronomy) so this can be a bit tricky, but if you're interested i'll send my python wrapper code for it.
So, take a look at ds9 and see it fits your need. To view numpy array in ds9, *. From python, save the array as a file (tofile method, better use "arr" as an extension) * in ds9, file-> open others -> open array. You need to select array dimension, type and endianness of the array. Regards, -JJ On Sat, Mar 8, 2008 at 11:17 AM, Chiara Caronna <[EMAIL PROTECTED]> wrote: > > Hello, > I am also interested in masking polygons and defining the polygon by > 'clicking' on the image... but I do not know anything about GUI.... does > anyone can help? Is there already something implemented? > Thanks! > Chiara > > > Date: Wed, 23 Jan 2008 13:50:15 +1300 > > From: [EMAIL PROTECTED] > > To: matplotlib-users@lists.sourceforge.net > > Subject: Re: [Matplotlib-users] Polygon masking possible? > > > > > > Hi Søren, > > > > I've put this back on the list in case it's useful to anyone else, or > > if there are better suggestions or improvements around. Hope you don't > > mind. > > > > On 22/01/2008, Søren Nielsen <[EMAIL PROTECTED]> wrote: > > > Yeah i'd like to see your code if I can.. > > > > import numpy as n > > > > def get_poly_pts(x, y, shape): > > """Creates convex polygon mask from list of corners. > > > > Parameters > > ---------- > > x : array_like > > x co-ordinates of corners > > y : array_like > > y co-ordinates of corners, in order corresponding to x > > shape : array_like > > dimension sizes of result > > > > Returns > > ------- > > build : ndarray > > 2-D array of shape shape with values True inside polygon > > > > Notes > > ----- > > Code is constrained to convex polygons by "inside" > > assessment criterion. > > > > """ > > x = n.asarray(x) > > y = n.asarray(y) > > shape = n.asarray(shape) > > npts = x.size # should probably assert x.size == y.size > > inds = n.indices( shape ) > > xs = inds[0] > > ys = inds[1] > > xav = n.round(x.mean()).astype(int) > > yav = n.round(y.mean()).astype(int) > > for i in xrange(npts): # iterate over pairs of co-ordinates > > j = (i + 1) % npts > > m = (y[j] - y[i])/(x[j] - x[i]) > > c = (x[j] * y[i] - x[i] * y[j])/(x[j] - x[i]) > > thisone = ( ys > m * xs + c ) > > if thisone[xav, yav] == False: > > thisone = ~thisone > > if i == 0: > > build = thisone > > else: > > build &= thisone > > return build > > > > (released under BSD licence) > > > > > I just needed the push over the edge to know how to draw on the canvas, > > > mapping clicks etc. since i'm still fairly new to matplotlib, so I think > > > your code will be helpfull. > > > > I hope so. As you can see this code doesn't do any of the drawing or > > click collecting, but the cookbook page should be able to guide you > > there. Ask again on the list if you have any further questions and > > we'll see if we can help. > > > > Also, the code assumes that the average co-ordinate is inside the > > shape - that's true for convex polygons, but not necessarily for > > arbitrary ones. I use if after taking a convex hull of a greater list > > of points (using the delaunay module in scipy (now in scikits, I > > hear)), which ensures convexity. You just need to be aware of that > > limitation. > > > > Cheers, > > > > A. > > -- > > AJC McMorland, PhD candidate > > Physiology, University of Auckland > > > > ------------------------------------------------------------------------- > > This SF.net email is sponsored by: Microsoft > > Defy all challenges. Microsoft(R) Visual Studio 2008. > > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > > _______________________________________________ > > Matplotlib-users mailing list > > Matplotlib-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > > ________________________________ > Express yourself instantly with MSN Messenger! MSN Messenger > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Matplotlib-users mailing list > Matplotlib-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > > ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
