checks geodataframe for crs before conversion (#1459)

Co-authored-by: maximlt <[email protected]>

doc/user_guide/Geographic_Data.ipynb

@@ -60,7 +60,7 @@
    "source": [
     "## Tiled web map\n",
     "\n",
-    "A [tiled web map](https://en.wikipedia.org/wiki/Tiled_web_map), or tile map, is an interactive map displayed on a web browser that is divided into small, pre-rendered image tiles, allowing for efficient loading and seamless navigation across various zoom levels and geographic areas. hvPlot allows to add a tile map as a basemap to a plot with the `tiles` parameter. Importantly, `tiles` is a parameter that can be used **without installing GeoViews**.\n",
+    "A [tiled web map](https://en.wikipedia.org/wiki/Tiled_web_map), or tile map, is an interactive map displayed on a web browser that is divided into small, pre-rendered image tiles, allowing for efficient loading and seamless navigation across various zoom levels and geographic areas. hvPlot allows us to add a tile map as a basemap to a plot with the `tiles` parameter. Importantly, `tiles` is a parameter that can be used **without installing GeoViews**.\n",
     "\n",
     "We'll display this dataframe of all US airports (including military bases overseas), the points are expressed in latitude/longitude coordinates:"
    ]
@@ -80,7 +80,7 @@
    "source": [
     "We'll first start by displaying the airports **without GeoViews** with tiles by setting `tiles=True`. \n",
     "\n",
-    "Under the hood, hvPlot projects lat/lon to easting/northing ([EPSG:4326](https://epsg.io/4326) to [EPSG:3857](https://epsg.io/3857)) coordinates without additional package dependencies if it detects that the values falls within expected lat/lon ranges, **unless the data is lazily loaded (dask / ibis).**\n",
+    "Under the hood, hvPlot projects lat/lon to easting/northing ([EPSG:4326](https://epsg.io/4326) to [EPSG:3857](https://epsg.io/3857)) coordinates without additional package dependencies if it detects that the values falls within expected lat/lon ranges, **unless the data is lazily loaded (dask / ibis), or the data is a spatialpandas object.**\n",
     "\n",
     "Note, **this feature is only available after `hvplot>=0.11.0`**; older versions, `hvplot<0.11.0`, require manual projection (see below)."
    ]

hvplot/converter.py

@@ -2170,12 +2170,13 @@ def _process_tiles_without_geo(self, data, x, y):
         elif not is_geodataframe(data) and (x is None or y is None):
             return data, x, y
 
-        if is_geodataframe(data):
-            if data.crs is not None:
-                data = data.to_crs(epsg=3857)
-            return data, x, y
-        elif not is_lazy_data(data):
+        if is_lazy_data(data):
             # To prevent eager evaluation: https://github.com/holoviz/hvplot/pull/1432
+            pass
+        elif is_geodataframe(data):
+            if getattr(data, 'crs', None) is not None:
+                data = data.to_crs(epsg=3857)
+        else:
             min_x = np.min(data[x])
             max_x = np.max(data[x])
             min_y = np.min(data[y])
@@ -2193,7 +2194,8 @@ def _process_tiles_without_geo(self, data, x, y):
                 data[new_y] = northing
                 if is_xarray(data):
                     data = data.swap_dims({x: new_x, y: new_y})
-                return data, new_x, new_y
+                x = new_x
+                y = new_y
         return data, x, y
 
     def chart(self, element, x, y, data=None):

hvplot/tests/testgeowithoutgv.py

@@ -8,12 +8,19 @@
 import pandas as pd
 import pytest
 
+from hvplot.util import is_geodataframe
+
 try:
     import dask.dataframe as dd
     import hvplot.dask  # noqa
 except ImportError:
     dd = None
 
+try:
+    import spatialpandas as spd
+except ModuleNotFoundError:
+    spd = None
+
 
 bk_renderer = hv.Store.renderers['bokeh']
 
@@ -83,3 +90,17 @@ def test_plot_with_dask(self, simple_df):
         assert isinstance(plot.get(0), hv.Tiles)
         bk_plot = bk_renderer.get_plot(plot)
         assert bk_plot.projection == 'mercator'
+
+    @pytest.mark.skipif(spd is None, reason='spatialpandas not installed')
+    def test_plot_without_crs(self):
+        square = spd.geometry.Polygon([(0.0, 0), (0, 1), (1, 1), (1, 0)])
+        sdf = spd.GeoDataFrame({'geometry': spd.GeoSeries([square, square]), 'name': ['A', 'B']})
+        plot = sdf.hvplot.polygons(tiles=True)
+
+        assert len(plot) == 2
+        assert is_geodataframe(sdf)
+        assert not hasattr(sdf, 'crs')
+        assert isinstance(plot.get(0), hv.Tiles)
+        assert isinstance(plot.get(1), hv.Polygons)
+        bk_plot = bk_renderer.get_plot(plot)
+        assert bk_plot.projection == 'mercator'  # projection enabled due to `tiles=True`