From: Dani Marti <daniel.marti@up...>  20050527 17:44:25

Hi all, I am using PyX to represent a vector field in 2D. I start from a data file with four columns, x y dx dy . . . . . . . . From this data I'd like to plot a vector with components (dx,dy) at point (x,y). This is matlab's "quiver" function convention (I should stick to this). I store each row of the data file as an element of a list, and then use it as the input for graph.data.list: g.plot(graph.data.list(list_vectors, x = 1, y = 2, size = 3, angle = 4), [graph.style.arrow()]) Everything is fine, except for two things:  the huge arrow heads (the longer the vector, the bigger the head). I'd like to have always the same size for the heads (preferably small, just to see to what direction the vector points to).  It is not the tail of the vector which is at (x,y), but the midpoint of it, and this is not what I want. Does anyone have any idea of how to solve this in a simple way? Is there a more convenient or simpler way of plotting 2D vector fields with PyX? By the way, could someone show an example of arrowattr=[], please? I didn't manage to find examples in the documentation. Thanks a lot in advance, Dani 