127 lines
3.2 KiB
Plaintext
127 lines
3.2 KiB
Plaintext
{
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"cells": [
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"import matplotlib.pyplot as plt\n",
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"%matplotlib inline\n",
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"\n",
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"import numpy as np\n",
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"\n",
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"import cartopy.crs as ccrs"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"Regridding vectors with quiver\n",
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"------------------------------\n",
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"\n",
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"This example demonstrates the regridding functionality in quiver (there exists\n",
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"equivalent functionality in :meth:`cartopy.mpl.geoaxes.GeoAxes.barbs`).\n",
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"\n",
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"Regridding can be an effective way of visualising a vector field, particularly\n",
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"if the data is dense or warped.\n",
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"\n",
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"### http://scitools.org.uk/iris/docs/v1.9.0/html/gallery.html\n"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"def sample_data(shape=(20, 30)):\n",
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" \"\"\"\n",
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" Returns ``(x, y, u, v, crs)`` of some vector data\n",
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" computed mathematically. The returned CRS will be a North Polar\n",
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" Stereographic projection, meaning that the vectors will be unevenly\n",
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" spaced in a PlateCarree projection.\n",
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"\n",
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" \"\"\"\n",
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" crs = ccrs.NorthPolarStereo()\n",
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" scale = 1e7\n",
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" x = np.linspace(-scale, scale, shape[1])\n",
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" y = np.linspace(-scale, scale, shape[0])\n",
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"\n",
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" x2d, y2d = np.meshgrid(x, y)\n",
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" u = 10 * np.cos(2 * x2d / scale + 3 * y2d / scale)\n",
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" v = 20 * np.cos(6 * x2d / scale)\n",
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"\n",
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" return x, y, u, v, crs\n"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"def main():\n",
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" plt.figure(figsize=(8, 10))\n",
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"\n",
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" x, y, u, v, vector_crs = sample_data(shape=(50, 50))\n",
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" ax1 = plt.subplot(2, 1, 1, projection=ccrs.PlateCarree())\n",
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" ax1.coastlines()\n",
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" ax1.set_extent([-45, 55, 20, 80], ccrs.PlateCarree())\n",
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" ax1.quiver(x, y, u, v, transform=vector_crs)\n",
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"\n",
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" ax2 = plt.subplot(2, 1, 2, projection=ccrs.PlateCarree())\n",
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" plt.title('The same vector field regridded')\n",
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" ax2.coastlines()\n",
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" ax2.set_extent([-45, 55, 20, 80], ccrs.PlateCarree())\n",
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" ax2.quiver(x, y, u, v, transform=vector_crs, regrid_shape=20)\n",
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"\n",
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" plt.show()\n"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"main()"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": []
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": []
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "Python 3",
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"language": "python",
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"name": "python3"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 3
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.8.5"
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}
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"nbformat": 4,
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"nbformat_minor": 1
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