pyic_view: Allow to toggle grid lines.

scripts/pyic_view.py

@@ -205,7 +205,8 @@ class view(object):
         res_menu.bind("<<ComboboxSelected>>", self.make_new_axis)
 
         # Button to activate zoom mode
-        self.zoom_button = ttk.Button(root, text="Enable Zoom", command=self.activate_zoom)
+        self.zoom_button = ttk.Button(root, text="Enable Zoom", 
+            command=self.activate_zoom)
         self.zoom_button.grid(row=3, column=2)
 
         # Variables to store zoom area
@@ -223,6 +224,12 @@ class view(object):
         res_menu.grid(row=3, column=3)
         res_menu.bind("<<ComboboxSelected>>", self.make_new_axis)
 
+        # checkbox for grid display
+        self.do_grid = tk.BooleanVar()
+        self.checkbox = tk.Checkbutton(root, text="Show grid", 
+            variable=self.do_grid, command=self.toggle_grid)
+        self.checkbox.grid(row=2, column=3)
+
         # initial plot
         self.plot_data()
         self.canvas.draw()
@@ -268,6 +275,7 @@ class view(object):
             # Ensure correct ordering of coordinates
             self.ax.set_xlim(min(x0, x1), max(x0, x1))
             self.ax.set_ylim(min(y0, y1), max(y0, y1))
+            #self.toggle_grid()
 
             # Remove the rectangle and redraw
             self.rect.remove()
@@ -330,6 +338,7 @@ class view(object):
             #self.X[valid], self.Y[valid], self.dai.data[valid], 
             self.X, self.Y, self.dai.data, 
             ax=self.ax, cax=self.cax)
+        # set ax limits
         if self.proj=="+proj=stere +lat_0=90 +lon_0=0":
             self.ax.set_xlim([-4660515.349812048,  4660515.349812048])
             self.ax.set_ylim([-4658959.2511977535, 4658959.2511977535])
@@ -339,6 +348,14 @@ class view(object):
         else:
             self.ax.set_xlim(self.X.min(), self.X.max())
             self.ax.set_ylim(self.Y.min(), self.Y.max())
+        # set ax labels
+        if self.proj=="None" or self.proj=="+proj=latlong":
+            #self.ax.set_xticks(np.arange(-180.,180.,45.))
+            #self.ax.set_yticks(np.arange(-90,90,45.))
+            pass
+        else:
+            self.ax.set_xticks([])
+            self.ax.set_yticks([])
         self.ax.set_facecolor('0.7')
         self.update_cmap()
         # set titles
@@ -475,6 +492,60 @@ class view(object):
           clim[1] = data.max().data
         return clim
 
+    def toggle_grid(self):
+        if self.do_grid.get():
+            print('Adding grid lines')
+            color='k'
+            linewidth=0.5
+            if self.proj=="+proj=stere +lat_0=90 +lon_0=0":
+                lon_c_vals = np.arange(-180.,180., 45.)
+                lat_c_vals = [40, 50, 60, 70, 80]
+            elif self.proj=="+proj=stere +lat_0=-90 +lon_0=0":
+                lon_c_vals = np.arange(-180.,180., 45.)
+                lat_c_vals = [-30, -40, -50, -60, -70, -80]
+            if self.proj=="None" or self.proj=="+proj=latlong":
+                lon_c_vals = self.ax.get_xticks()
+                lat_c_vals = self.ax.get_yticks()
+            else: 
+                lon_c_vals = np.arange(-180.,180., 45.)
+                lat_c_vals = np.arange(-90.,90., 45.)
+            #transformer = Proj.from_pipeline(self.proj)
+            nc = 51
+    
+            X_c = np.empty((1,nc))
+            Y_c = np.empty((1,nc))
+            for nn, lat_c_val in enumerate(lat_c_vals):
+              lon_c = np.linspace(-180,180,nc)
+              lat_c = lat_c_val*np.ones(nc)
+              if self.proj!="None":
+                  x_c, y_c = self.transformer.transform(
+                      lon_c, lat_c, direction='FORWARD')
+              else:
+                  x_c, y_c = lon_c, lat_c
+              X_c = np.concatenate([X_c, x_c[np.newaxis,:]], axis=0)
+              Y_c = np.concatenate([Y_c, y_c[np.newaxis,:]], axis=0)
+            for nn, lon_c_val in enumerate(lon_c_vals):
+              lon_c = lon_c_val*np.ones(nc)
+              lat_c = np.linspace(-90,90,nc)
+              if self.proj!="None":
+                  x_c, y_c = self.transformer.transform(
+                      lon_c, lat_c, direction='FORWARD')
+              else:
+                  x_c, y_c = lon_c, lat_c
+              X_c = np.concatenate([X_c, x_c[np.newaxis,:]], axis=0)
+              Y_c = np.concatenate([Y_c, y_c[np.newaxis,:]], axis=0)
+            self.hgs = []
+            for nn in range(X_c.shape[0]):
+                hg, = self.ax.plot(X_c[nn,:], Y_c[nn,:], 
+                    color=color, linewidth=linewidth)
+                self.hgs.append(hg)
+                #print(f'nn = {nn}, {self.hgs}')
+        else:
+            print('Removing grid lines')
+            for hg in self.hgs:
+                hg.remove()
+        self.canvas.draw()
+
     # capture mouse click, print coordinates and data
     def on_click(self, event):
         # Avoid clicking outside the axes