Source code for mpas_tools.ocean.viz.inset

import matplotlib.path
import matplotlib.ticker as mticker
import cartopy
import as ccrs
import numpy
import shapely.geometry

from geometric_features.plot import subdivide_geom

[docs] def add_inset(fig, fc, latlonbuffer=45., polarbuffer=5., width=1.0, height=1.0, lowerleft=None, xbuffer=None, ybuffer=None, maxlength=1.): """ Plots an inset map showing the location of a transect or polygon. Shapes are plotted on a polar grid if they are entirely poleward of +/-50 deg. latitude and with a lat/lon grid if not. Parameters ---------- fig : ``matplotlib.figure.Figure`` A matplotlib figure to add the inset to fc : ``geometric_features.FeatureCollection`` A collection of regions, transects and/or points to plot in the inset latlonbuffer : float, optional The number of degrees lat/lon to use as a buffer around the shape(s) to plot if a lat/lon plot is used. polarbuffer : float, optional The number of degrees latitude to use as a buffer equatorward of the shape(s) in polar plots width, height : float, optional width and height in inches of the inset lowerleft : pair of floats, optional the location of the lower left corner of the axis in inches, default puts the inset in the upper right corner of ``fig``. xbuffer, ybuffer : float, optional right and top buffers from the top-right corner (in inches) if lowerleft is ``None``. maxlength : float or ``None``, optional Any segments longer than maxlength will be subdivided in the plot to ensure curvature. If ``None``, no subdivision is performed. Returns ------- inset : ``matplotlib.axes.Axes`` The new inset axis """ # Authors # ------- # Xylar Asay-Davis minLon, minLat, maxLon, maxLat = _get_bounds(fc) figsize = fig.get_size_inches() width /= figsize[0] height /= figsize[1] if lowerleft is None: if xbuffer is None: xbuffer = 0.1*width else: xbuffer /= figsize[0] if ybuffer is None: ybuffer = xbuffer*figsize[0]/figsize[1] else: ybuffer /= figsize[1] lowerleft = [1.0 - width - xbuffer, 1.0 - height - ybuffer] else: lowerleft = [lowerleft[0]/figsize[0], lowerleft[1]/figsize[1]] bounds = [lowerleft[0], lowerleft[1], width, height] if maxLat <= -50: # an Antarctic-focused map makes the most sense inset = fig.add_axes(bounds, projection=ccrs.SouthPolarStereo()) extent = [-180., 180., -90., max(-65., maxLat+polarbuffer)] _set_circular_boundary(inset) xlocator = mticker.FixedLocator(numpy.linspace(-180., 180., 9)) ylocator = mticker.FixedLocator(numpy.linspace(-90., -50., 9)) elif minLat >= 50: # an Arctic-focused map makes the most sense inset = fig.add_axes(bounds, projection=ccrs.NorthPolarStereo()) extent = [-180, 180, min(65., minLat-polarbuffer), 90] _set_circular_boundary(inset) xlocator = mticker.FixedLocator(numpy.linspace(-180., 180., 9)) ylocator = mticker.FixedLocator(numpy.linspace(50., 90., 9)) else: inset = fig.add_axes(bounds, projection=ccrs.PlateCarree()) extent = [max(-180., minLon-latlonbuffer), min(180., maxLon+latlonbuffer), max(-90., minLat-latlonbuffer), min(90., maxLat+latlonbuffer)] xlocator = None ylocator = None # kind of like "top" justified -- graphics are toward the "north" end of # the subplot inset.set_anchor('N') inset.set_extent(extent, ccrs.PlateCarree()) inset.add_feature(cartopy.feature.LAND, zorder=1) inset.add_feature(cartopy.feature.OCEAN, zorder=0) gl = inset.gridlines(crs=ccrs.PlateCarree(), draw_labels=False, linewidth=0.5, color='gray', alpha=0.5, linestyle='--') if xlocator is not None: gl.xlocator = xlocator if ylocator is not None: gl.ylocator = ylocator for feature in fc.features: geomtype = feature['geometry']['type'] shape = shapely.geometry.shape(feature['geometry']) if maxlength is not None: shape = subdivide_geom(shape, shape.geom_type, maxlength) if geomtype in ['Polygon', 'MultiPolygon']: inset.add_geometries((shape,), crs=ccrs.PlateCarree(), edgecolor='blue', facecolor='blue', alpha=0.4, linewidth=1.) elif geomtype in ['Point', 'MultiPoint']: point_x, point_y = shape.xy inset.scatter(point_x, point_y, s=9, color='k', transform=ccrs.PlateCarree(), edgecolors='face') else: inset.add_geometries((shape,), crs=ccrs.PlateCarree(), edgecolor='k', facecolor='none', alpha=1., linewidth=1.) # put a red point at the beginning and a blue point at the end # of the transect to help show the orientation begin = shape.coords[0] end = shape.coords[-1] inset.plot(begin[0], begin[1], color='r', marker='o', markersize=3., transform=ccrs.PlateCarree()) inset.plot(end[0], end[1], color='g', marker='o', markersize=3., transform=ccrs.PlateCarree()) return inset
def _set_circular_boundary(ax): """Set the boundary of the given axis to be circular (for a polar plot)""" # Compute a circle in axes coordinates, which we can use as a boundary # for the map. We can pan/zoom as much as we like - the boundary will be # permanently circular. theta = numpy.linspace(0, 2*numpy.pi, 100) center = numpy.array([0.5, 0.5]) radius = 0.5 verts = numpy.vstack([numpy.sin(theta), numpy.cos(theta)]).T circle = matplotlib.path.Path(verts * radius + center) ax.set_boundary(circle, transform=ax.transAxes) def _get_bounds(fc): """Compute the lon/lat bounding box for all transects and regions""" bounds = shapely.geometry.GeometryCollection() for feature in fc.features: shape = shapely.geometry.shape(feature['geometry']) shape_bounds =*shape.bounds) bounds =*bounds.union(shape_bounds).bounds) return bounds.bounds