quiver2

Community matplotlib-users
#1

Hi,

I am tring to figure out how to use the c argument to the quiver2 function.

I want to be able to color my arrows proportionally to their size.

I have tried this and it doesn’ t work as I imagined:

c = sqrt((array(u)-array(x))**2+(array(v)-array(y))**2)

quiver2(x,y,u,v,c)

the docstring on quiver2 is not clear on how c works, any help will be appreciated.

thanks,

···

–
Flávio Codeço Coelho

registered Linux user # 386432

“Laws are like sausages. It’s better not to see them being made.”
Otto von Bismark

#2

Flavio Coelho wrote:

Hi,

I am tring to figure out how to use the c argument to the quiver2 function.

I want to be able to color my arrows proportionally to their size.

I have tried this and it doesn' t work as I imagined:

c = sqrt((array(u)-array(x))**2+(array(v)-array(y))**2)

The length of the arrow is proportional to sqrt(u**2 + v**2),
not to sqrt((u-x)**2 + (v-y)**2).

Is the reason you are not getting what you expect?

Eric

···

quiver2(x,y,u,v,c)

the docstring on quiver2 is not clear on how c works, any help will be appreciated.

#3

Thanks Eric,

in fact it depends on if x,y are 0 or not. But I got it to work it now.

thanks,

Flávio

···

On 8/22/06, Eric Firing < efiring@…202…> wrote:

Flavio Coelho wrote:

Hi,

I am tring to figure out how to use the c argument to the quiver2 function.

I want to be able to color my arrows proportionally to their size.

I have tried this and it doesn’ t work as I imagined:

c = sqrt((array(u)-array(x))**2+(array(v)-array(y))**2)

The length of the arrow is proportional to sqrt(u2 + v2),
not to sqrt((u-x)**2 + (v-y)**2).

Is the reason you are not getting what you expect?

Eric

quiver2(x,y,u,v,c)

the docstring on quiver2 is not clear on how c works, any help will be
appreciated.

–
Flávio Codeço Coelho
registered Linux user # 386432

“Laws are like sausages. It’s better not to see them being made.”
Otto von Bismark

#4

Flavio,

One more point: please do not use quiver2 directly. Instead, use quiver, which will call quiver2 unless it finds a keyword argument that exists only in the old version of quiver. The name quiver2 is used only temporarily to provide this compatibility, which will be removed in a future release.

Eric

Flavio Coelho wrote:

···

Hi,

I am tring to figure out how to use the c argument to the quiver2 function.