add loading indicator

app.py

@@ -11,6 +11,7 @@ from utils import (
     DATASHADER_URL,
     DESCRIPTION,
     MAJOR_TOM_LOGO,
+    MAJOR_TOM_LYRICS,
     MAJOR_TOM_PICTURE,
     MAJOR_TOM_REF_URL,
     PANEL_LOGO,
@@ -178,35 +179,62 @@ class ImageInput(pn.viewable.Viewer):
                 self.plot = hv.RGB(image_array).opts(xaxis=None, yaxis=None)
 
 
-pn.extension("tabulator", design="fast")
+class App(param.Parameterized):
+    sidebar = param.Parameter()
+    main = param.Parameter()
 
-dataset = DatasetInput()
-app = MapInput(data=dataset.param.data)
-image_input = ImageInput(data=app.param.data_selected)
+    def __init__(self, **params):
+        super().__init__(**params)
 
+        self.sidebar = self._create_sidebar()
+        self.main = pn.FlexBox(
+            pn.Column(
+                pn.Row(
+                    pn.indicators.LoadingSpinner(value=True, size=50),
+                    "**Loading data...**",
+                ),
+                MAJOR_TOM_LYRICS,
+            )
+        )
 
-main = pn.Column(
-    pn.FlexBox(
-        pn.Column(dataset, app),
-        image_input,
-    ),
-)
-sidebar = pn.Column(
-    pn.pane.Image(
-        MAJOR_TOM_LOGO, link_url=MAJOR_TOM_REF_URL, sizing_mode="stretch_width"
-    ),
-    pn.pane.Image(
-        MAJOR_TOM_PICTURE, link_url=MAJOR_TOM_REF_URL, sizing_mode="stretch_width"
-    ),
-    DESCRIPTION,
-    pn.pane.Image(PANEL_LOGO, link_url=PANEL_URL, width=200, margin=(10, 20)),
-    pn.pane.Image(DATASHADER_LOGO, link_url=DATASHADER_URL, width=200, margin=(10, 20)),
-)
+        pn.state.onload(self._update_main)
+
+    def _create_sidebar(self):
+        return pn.Column(
+            pn.pane.Image(
+                MAJOR_TOM_LOGO, link_url=MAJOR_TOM_REF_URL, sizing_mode="stretch_width"
+            ),
+            pn.pane.Image(
+                MAJOR_TOM_PICTURE,
+                link_url=MAJOR_TOM_REF_URL,
+                sizing_mode="stretch_width",
+            ),
+            DESCRIPTION,
+            pn.pane.Image(PANEL_LOGO, link_url=PANEL_URL, width=200, margin=(10, 20)),
+            pn.pane.Image(
+                DATASHADER_LOGO, link_url=DATASHADER_URL, width=200, margin=(10, 20)
+            ),
+        )
+
+    def _create_main_content(self):
+        dataset = DatasetInput()
+        map_input = MapInput(data=dataset.param.data)
+        image_input = ImageInput(data=map_input.param.data_selected)
+
+        return pn.Column(dataset, map_input), image_input
+
+    def _update_main(self):
+        self.main[:] = list(self._create_main_content())
+
+
+pn.extension("tabulator", design="fast")
+
+app = App()
 
 pn.template.FastListTemplate(
     title="Major TOM Explorer",
-    main=[main],
-    sidebar=[sidebar],
+    main=[app.main],
+    sidebar=[app.sidebar],
     main_layout=None,
     accent="#003247",  # "#A01346"
 ).servable()

download_datasets.py

@@ -4,4 +4,4 @@ for dataset in DATASETS:
     print(f"downloading {dataset}")
     get_meta_data(dataset=dataset)
 
-print("finished downloading datasets")
+print("finished downloading datasets")

utils.py

@@ -36,6 +36,63 @@ To find a sample, navigate on the map to a place of interest. Click the map to f
 
 """
 
+MAJOR_TOM_LYRICS = """
+Standing there alone, the ship is waiting
+All systems are go, are you sure?
+Control is not convinced, but the computer
+Has the evidence, no need to abort
+The countdown starts
+
+Watching in a trance, the crew is certain
+Nothing left to chance, all is working
+Trying to relax up in the capsule
+"Send me up a drink, " jokes **Major Tom**
+The count goes on
+
+Four, three, two, one
+
+Earth below us, drifting, falling
+Floating weightless, calling, calling home
+
+Second stage is cut, we're now in orbit
+Stabilizers up, running perfect
+Starting to collect requested data
+"What will it affect when all is done?"
+Thinks **Major Tom**
+
+Back at ground control, there is a problem
+Go to rockets full, not responding
+"Hello **Major Tom**, are you receiving?
+Turn the thrusters on, we're standing by"
+There's no reply
+
+Four, three, two, one
+
+Earth below us, drifting, falling
+Floating weightless, calling, calling home
+
+Across the stratosphere a final message
+"Give my wife my love, " then nothing more
+Far beneath the ship, the world is mourning
+They don't realize he's alive
+No one understands, but **Major Tom** sees
+"Now the light commands, this is my home
+I'm coming home"
+
+Earth below us, drifting, falling
+Floating weightless, coming home
+Earth below us, drifting, falling
+Floating weightless, coming home
+Earth below us, drifting, falling
+Floating weightless, coming, coming home
+
+Home
+Home
+Home
+Home
+Home
+"""
+
 hv.extension("bokeh")
 
 opts.defaults(