Tips for choosing profile locations#
To help you pick the locations of your profiles, here are a few resources.
EPSG:3031 Polar Stereographic map#
Read x/y coordinates off this map to choose approximate start/end profile points.
[1]:
import pygmt
fig = pygmt.Figure()
region = (-2700000, 2700000, -2700000, 2700000)
e, w, n, s = region
fig_height = 90 # in mm
fig_width = fig_height * (w - e) / (s - n)
fig_ratio = (s - n) / (fig_height / 1000)
fig_proj = "x1:" + str(fig_ratio)
fig_proj_ll = "s0/-90/-71/1:" + str(fig_ratio)
fig.coast(
region=(*region, "+ue"),
projection=fig_proj_ll,
shorelines="0.5p,black",
land="skyblue",
)
fig.coast(
projection=fig_proj_ll, area_thresh="+ag", shorelines="0.5p,black", land="gray"
)
with pygmt.config(
MAP_GRID_PEN_PRIMARY=".4p,dimgray", MAP_GRID_PEN_SECONDARY=".75p,black"
):
fig.basemap(
projection=fig_proj,
frame=[
"sxa500000g500000+a30+leasting (m)",
"pxg250000",
"sya500000g500000+lnorthing (m)",
"pyg250000",
],
)
fig.show()
Or if you install ipyleaflet
with mamba install ipyleaflet
, the below code wil show and interactive map and clicking will give coordinates in EPSG 3031. See the tutorial profile walkthrough
for an example of extracting a profile from the interactive map, or tutorial regions_walkthrough
for an example of defining a region from the interactive map.
[1]:
from polartoolkit import maps
m = maps.interactive_map()
Make custom shapefile in QGIS#
QGIS, especially with the Quantarctica package, is an easy way to make a custom shapefile. This can then be used with polartoolkit
to sample data along the file.
To make the shapefile in QGIS: * Layer -> Create Layer -> New Shapefile Layer * For Geometry Type
, select Polygon
* Select EPSG:3031
for the coordinate reference system * Save to the same directory as your python file you want to work with.