Merge pull request #32 from mathause/fix/ex3_1

Fix/ex3 1 closes #17 and #19
C2SM · May 25, 2018 · f51a7de · f51a7de
2 parents a60faa3 + 9df4c8a
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diff --git a/Part3/ex3_1_intro_scatter.ipynb b/Part3/ex3_1_intro_scatter.ipynb
@@ -22,8 +22,8 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "import xarray as xr\n",
     "import matplotlib.pyplot as plt\n",
+    "import xarray as xr\n",
     "\n",
     "%matplotlib inline"
    ]
@@ -83,7 +83,7 @@
     "\n",
     "To plot a map, we have to specify a `projection` for the axes. We start with the `PlateCarree` projection, which is a [equirectangular projection](https://en.wikipedia.org/wiki/Equirectangular_projection). This projection maps x to be the value of the longitude and y to be the value of the latitude.\n",
     "\n",
-    "This creates a special kind of axes (a `<cartopy.mpl.geoaxes.GeoAxesSubplot>`) which is derived from the normal `axes`. As such it includes some special commands (which we'll get to know), one of them called `ax.coatlines()` which is an easy way to add the coastlines.\n",
+    "This creates a special kind of axes (a `<cartopy.mpl.geoaxes.GeoAxesSubplot>`) which is derived from the normal `axes`. As such it includes some special commands (which we'll get to know), one of them called `ax.coastlines()` which is an easy way to add the coastlines.\n",
     "\n",
     "Ok, let's get started:\n"
    ]
@@ -287,13 +287,17 @@
   },
   {
    "cell_type": "markdown",
-   "metadata": {},
+   "metadata": {
+    "hide_input": false
+   },
    "source": [
     "### Exercise\n",
     "\n",
-    " * Color the points according to their temperature (TEMP)\n",
+    " * Color the points according to their temperature (`ATL.TEMP` etc.)\n",
+    " > You will need to remove the `color=` argument.\n",
     " * restrict the range of the colormap to 0...25\n",
-    " * add a colorbar"
+    " * add a colorbar\n",
+    " > `colorbar` will require a `mappable`, use `h = ax.scatter`"
    ]
   },
   {
@@ -347,15 +351,46 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "The colorbar is to big for the map! However, this is not straight forward to correct... You will learn how to do this later.\n",
+    "### Note\n",
+    "\n",
+    " > The colorbar is to big for the map! However, this is not straightforward to correct... You will learn how to do this later.\n",
+    "\n",
+    " > If the range of the colormap is not set to the same values for the three plots, it will be choosen according to the range of the data."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "ax = plt.axes(projection=ccrs.PlateCarree())\n",
+    "\n",
+    "ax.coastlines()\n",
+    "\n",
+    "opt = dict(s=15)\n",
+    "\n",
+    "h0 = ax.scatter(ATL.lon, ATL.lat, c=ATL.TEMP, **opt)\n",
+    "h1 = ax.scatter(IND.lon, IND.lat, c=IND.TEMP, **opt)\n",
+    "h2 = ax.scatter(PAC.lon, PAC.lat, c=PAC.TEMP, **opt)\n",
     "\n",
+    "plt.colorbar(h0)\n",
+    "plt.colorbar(h1)\n",
+    "plt.colorbar(h2)\n",
     "\n",
+    "ax.set_global()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
     "## Projections\n",
     "\n",
     "cartopy offers [20ish different projections](http://scitools.org.uk/cartopy/docs/v0.15/crs/projections.html). Have a look at them. Unfortunately some important projections are missing (e.g. Hammer and Aitoff).\n",
     "\n",
     "### Exercise\n",
-    " * redo the plot but select a projection from the website."
+    " * redo the plot but select a different projection from the website."
    ]
   },
   {
@@ -594,15 +629,14 @@
     "\n",
     "cartopy can make use of many online geographical data sources. See examples under [Web Services](http://scitools.org.uk/cartopy/docs/latest/gallery.html#web-services).\n",
     "\n",
-    "The best thing about this is that you have access and easy ways to plot all the data available at [naturalearthdata.com]\n",
-    "http://www.naturalearthdata.com/. Naturalearth data provides high quality geo data for free.\n",
+    "The best thing about this is that you have access and easy ways to plot all the data available at [naturalearthdata.com](http://www.naturalearthdata.com/). Naturalearth data provides high quality geo data for free.\n",
     "\n",
     "See [naturalearthdata.com/features](http://www.naturalearthdata.com/features/) for all that is available.\n",
     "\n",
     "For example `ax.coastline()` displays the following data: [110m-coastline](http://www.naturalearthdata.com/downloads/110m-physical-vectors/110m-coastline/).\n",
     "\n",
     "Note:\n",
-    "> The data is downloaded and stored the first time you use it."
+    "> The data is downloaded and stored the first time you use it, so this might take a minute or so."
    ]
   },
   {
@@ -633,13 +667,14 @@
     "# adding a slightly textured image of the globe\n",
     "ax.stock_img();\n",
     "\n",
+    "# ==========================================\n",
+    "# NaturalEarthData\n",
     "\n",
     "# some data is easily accessible\n",
     "ax.add_feature(cfeature.BORDERS)\n",
     "ax.add_feature(cfeature.LAKES, edgecolor='0.1')\n",
     "\n",
-    "# for some data you need to know the name:\n",
-    "\n",
+    "# for some data you need to know the name (e.g. the States of the US and Canada):\n",
     "states = cfeature.NaturalEarthFeature('cultural', 'admin_1_states_provinces_lakes', '50m')\n",
     "ax.add_feature(states, edgecolor='0.2', facecolor='none', lw=0.5)"
    ]
@@ -742,7 +777,9 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "ax = plt.axes(projection=ccrs.PlateCarree())\n",
+    "projection = ccrs.PlateCarree()\n",
+    "\n",
+    "ax = plt.axes(projection=projection)\n",
     "\n",
     "\n",
     "ax.plot(ch.lon, ch.lat, transform=ccrs.PlateCarree())\n",
@@ -790,7 +827,7 @@
     "Note:\n",
     "> For a reason I don't know it is not possible to make an empty scatter plot. So I placed them at 0, 0, and then we need to set the extent explicitely.\n",
     "\n",
-    "> `xarray` automatically sets labels when we plot it's data. Therefore we use `ch.lon.values` to get rid of the additional elements in the leged."
+    "> `xarray` automatically sets labels when we plot it's data. Therefore we use `ch.lon.values` to get rid of the additional elements in the legend."
    ]
   },
   {
@@ -823,13 +860,6 @@
     "\n",
     "ax.set_extent((5.49, 10.77, 45.7, 48.3), ccrs.PlateCarree())"
    ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": []
   }
  ],
  "metadata": {

diff --git a/WHATS_NEW.md b/WHATS_NEW.md
@@ -8,6 +8,8 @@
  * use `np.asarray` instead of `np.array`, because it does not copy the data (closes [GH2][i2])
  * explain arguments of `plt.subplots` (closes [GH6][i6] and [GH7][i7])
  * explain why np.newaxis is needed in ex1_2 (broadcasting) (closes [GH10][i10])
+ * ex3_2 fix typos and colormap range (closes [GH17][i17] and [GH19][i19])
+
 
 
 ### 1.0.0 (06.02.2018)
@@ -22,5 +24,8 @@
 [i6]: https://github.com/C2SM/pyvis/issues/6
 [i7]: https://github.com/C2SM/pyvis/issues/7
 [i10]: https://github.com/C2SM/pyvis/issues/10
+[i17]: https://github.com/C2SM/pyvis/issues/17
+[i19]: https://github.com/C2SM/pyvis/issues/19
+