indicating directions on stereographic projection.

Community matplotlib-users
1

Hello,

I have stereographic projection of the pole. I need to indicate the directions like north,south,east, west, north-east, north-west and so on. Is there any way to do so?

Thanks
Sourav

2

I am **very far** from a GIS expert, but I believe that the cardinal
directions are ambiguous at the poles. In other words, if you're standing
on the North Pole, it'd difficult to head in any direction that's not
towards the south pole.

Curious to hear if I'm wrong, though.

-paul

···

On Wed, Oct 23, 2013 at 9:30 PM, Sourav Chatterjee <srv.sxc@...287...>wrote:

Hello,

I have stereographic projection of the pole. I need to indicate the
directions like north,south,east, west, north-east, north-west and so on.
Is there any way to do so?

Thanks
Sourav

3

I'm sure I'm even farther from being a GIS expert (and probably farther from one as well :), but I think you raise an interesting point. My compass would give me directions at the geographic north pole, given that the magnetic north pole is different from the geographic north pole. I'm curious how valid it would be to use magnetic north to assign directions at the geographic north pole. My guess is not very valid, but kind of cool nonetheless.

Jason

···

On 11/6/13 1:10 PM, Paul Hobson wrote:

I am **very far** from a GIS expert, but I believe that the cardinal
directions are ambiguous at the poles. In other words, if you're
standing on the North Pole, it'd difficult to head in any direction
that's not towards the south pole.

Curious to hear if I'm wrong, though.

4

Sourav - Are you by chance trying to make a stereonet? If so, your question makes a bit more sense. If that’s what you’re doing, have a look at mplstereonet. https://github.com/joferkington/mplstereonet It currently doesn’t support polar stereonets, but that’s something I’ve been meaning to add for a long time.

If that’s not what you’re doing, then perhaps you wanted something similar to this? (The directions don’t have much meaning, as others have already pointed out):

from mpl_toolkits.basemap import Basemap

import numpy as np
import matplotlib.pyplot as plt

m = Basemap(projection=‘npstere’,boundinglat=10,lon_0=270,resolution=‘l’)
m.drawcoastlines()
m.fillcontinents(color=‘coral’,lake_color=‘aqua’)

m.drawmapboundary(fill_color=‘aqua’)

draw parallels and meridians.

m.drawparallels(np.arange(-80.,80.,20.))
ticks = m.drawmeridians(np.arange(-180.,180.,20.),
labels=[True, True, True, True])

Change the meridian label at 0 and 180 to East and West

for value, label in zip([0.0, -180.0], [‘East’, ‘West’]):
ticks[value][1][0].set_text(label)

plt.show()

Hope that helps!

-Joe

···

On Wed, Nov 6, 2013 at 1:34 PM, Jason Grout <jason-sage@…2130…> wrote:

On 11/6/13 1:10 PM, Paul Hobson wrote:

I am very far from a GIS expert, but I believe that the cardinal

directions are ambiguous at the poles. In other words, if you’re

standing on the North Pole, it’d difficult to head in any direction

that’s not towards the south pole.

Curious to hear if I’m wrong, though.

I’m sure I’m even farther from being a GIS expert (and probably farther

from one as well :), but I think you raise an interesting point. My

compass would give me directions at the geographic north pole, given

that the magnetic north pole is different from the geographic north

pole. I’m curious how valid it would be to use magnetic north to assign

directions at the geographic north pole. My guess is not very valid,

but kind of cool nonetheless.

Jason

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5

Paul Hobson wrote:

···

On Wed, Oct 23, 2013 at 9:30 PM, Sourav Chatterjee <srv.sxc@...287...> wrote:

>
> Hello,
>
> I have stereographic projection of the pole. I need to indicate the directions like
> north,south,east, west, north-east, north-west and so on. Is there any way to do so?
>
> Thanks
> Sourav
>
> I am **very far** from a GIS expert, but I believe that the cardinal directions are ambiguous at
> the poles. In other words, if you're standing on the North Pole, it'd difficult to head in any
> direction that's not towards the south pole.
>
> Curious to hear if I'm wrong, though.
>
Yes, on the North Pole, every direction is South, on the South Pole, every direction is North.
--
Piet van Oostrum <piet@...4462...>
WWW: http://pietvanoostrum.com/
PGP key: [8DAE142BE17999C4]

6

Thanks everyone for your views. Joe- Thank you for the link. It’s really worthy.

···

On Thu, Nov 7, 2013 at 3:53 AM, Piet van Oostrum <piet@…4462…> wrote:

Paul Hobson wrote:

On Wed, Oct 23, 2013 at 9:30 PM, Sourav Chatterjee <srv.sxc@…287…> wrote:

Hello,

I have stereographic projection of the pole. I need to indicate the directions like

north,south,east, west, north-east, north-west and so on. Is there any way to do so? 

Thanks

Sourav

I am very far from a GIS expert, but I believe that the cardinal directions are ambiguous at

the poles. In other words, if you’re standing on the North Pole, it’d difficult to head in any

direction that’s not towards the south pole.

Curious to hear if I’m wrong, though.

Yes, on the North Pole, every direction is South, on the South Pole, every direction is North.

–

Piet van Oostrum <piet@…4462…>

WWW: http://pietvanoostrum.com/

PGP key: [8DAE142BE17999C4]

–
Sourav Chatterjee
Trainee Scientist

Indian Institute of Tropical Meteorology, Pune