Add option to disable Mercator calculation for OpenStreetMaps (#32)

* Add disable mercator optional kwarg

* Always fave filename

* Add example and update README

* Clean generated example plots

* Bump patch version

* Add image to README

* Remove obsolete save dir test

* Add unittest for disable mercator

* Consolidate osm conftest fixtures

* change order of linting in makefile test

* flake8

* Change mapper type instead of checking class var

* Flake8

* Remove incorrect desc from ocstring

* Update stand constructor docstring

* Code formatting

Author: misimpso

Makefile

@@ -31,6 +31,7 @@ clean:
 	rm -rf $(PROJ_BASE)/docs/_build/*
 	rm -f $(PROJ_BASE)/coverage.xml
 	rm -f $(PROJ_BASE)/.coverage
+	find $(PROJ_BASE)/examples -type f ! -name '*.py' -delete
 
 PHONY: sparkling
 sparkling: clean
@@ -39,5 +40,5 @@ sparkling: clean
 
 PHONY: test
 test:
-	$(VENVPYTHON) -m flake8 .
 	$(VENVPYTHON) -m pytest
+	$(VENVPYTHON) -m flake8 .

README.md

@@ -59,6 +59,8 @@ plot.save()
 ---
 ## OpenStreetMaps
 WKTPlot now supports the ability to integrate with OpenStreetMaps. Shape coordinates will be projected to the Mercator coordinate system, which appear to distort shape proportions compared to standard geometric projection.
+
+If your shape data has already been projected, you can disable the Mercator calculation by setting the `disable_mercator` parameter when creating the plot object. See [Advanced Usage](#advanced-usage) for an example.
 ```python
 # Import OpenStreetMaps plotting class
 from wktplot.plots.osm import OpenStreetMapsPlot
@@ -76,26 +78,42 @@ plot.save()
 ---
 
 ## Advanced Usage
-Example for plotting from shapefile. Shapefile is of California's county boundaries from [here](https://data.ca.gov/dataset/ca-geographic-boundaries).
+Example for plotting from shapefile. Shapefile is of California's county boundaries, download from [here](https://data.ca.gov/dataset/ca-geographic-boundaries).
 ```python
 import shapefile  # pyshp module
 
-from random import randrange
+from bokeh.palettes import Magma6
+from pathlib import Path
+from random import choice
 from shapely.geometry import Polygon
-from wktplot import WKTPlot
+from wktplot.plots.osm import OpenStreetMapsPlot
 
-def get_rand_color():
-    return f"#{randrange(0, 0xffffff):0>6x}"
 
-plot = WKTPlot(title="California Counties", save_dir="~/scratch")
-with shapefile.Reader("~/scratch/CA_Counties_TIGER2016.shp") as shp:
+COUNTIES_PATH = Path("/path/to/CA_Counties_TIGER2016.shp")
+
+# Create plot and disable mercator calculation
+# because data has already been projected
+plot = OpenStreetMapsPlot(
+    title="California Counties 2016",
+    height=1000,
+    width=1000,
+    disable_mercator=True,
+)
+
+# Read shapefile data points from file
+with shapefile.Reader(COUNTIES_PATH) as shp:
     for shape in shp.shapes():
-        p = Polygon(shape.points)
-        plot.add_shape(p, fill_color=get_rand_color())
+        plot.add_shape(
+            shape=Polygon(shape.points),
+            fill_color=choice(Magma6),
+            fill_alpha=0.75,
+        )
+
+# Save plot to disk [./california_counties_2016.html]
 plot.save()
 ```
 Which will result in this output:
-![CaliforniaCounties](https://i.imgur.com/YPQQlml.png)
+![CaliforniaCounties2016](https://i.imgur.com/lxac0JL.png)
 
 ---
 

examples/advanced_shapefile.py

@@ -0,0 +1,31 @@
+import shapefile  # pyshp module
+
+from bokeh.palettes import Magma6
+from pathlib import Path
+from random import choice
+from shapely.geometry import Polygon
+from wktplot.plots.osm import OpenStreetMapsPlot
+
+
+COUNTIES_PATH = Path("/path/to/CA_Counties_TIGER2016.shp")
+
+# Create plot and disable mercator calculation
+# because data has already been projected
+plot = OpenStreetMapsPlot(
+    title="California Counties 2016",
+    height=1000,
+    width=1000,
+    disable_mercator=True,
+)
+
+# Read shapefile data points from file
+with shapefile.Reader(COUNTIES_PATH) as shp:
+    for shape in shp.shapes():
+        plot.add_shape(
+            shape=Polygon(shape.points),
+            fill_color=choice(Magma6),
+            fill_alpha=0.75,
+        )
+
+# Save plot to disk [./california_counties_2016.html]
+plot.save()

src/wktplot/__init__.py

@@ -1,3 +1,3 @@
 from .plots.standard import WKTPlot  # noqa: F401
 
-__version__ = "2.3.1"
+__version__ = "2.3.2"

src/wktplot/mappers/standard.py

@@ -9,33 +9,6 @@
 
 class StandardMapper(BaseMapper):
 
-    @classmethod
-    def _get_point_coords(cls, shape: Point) -> Tuple[float, float]:
-        return shape.x, shape.y
-
-    @classmethod
-    def _get_line_string_coords(cls, shape: Union[LineString, LinearRing]) -> Tuple[List[float], List[float]]:
-        x, y = map(list, shape.xy)
-        return x, y
-
-    @classmethod
-    def _get_polygon_coords(self, shape: Polygon) -> Tuple[List[List[float]], List[List[float]]]:
-
-        ext_x, ext_y = map(list, shape.exterior.xy)
-
-        # Shape coordinates start and end with the same value.
-        # Chop off last coordinate for Bokeh.
-        x: List[float] = [ext_x[:-1]]
-        y: List[float] = [ext_y[:-1]]
-
-        for intr_shape in shape.interiors:
-            intr_x, intr_y = map(list, intr_shape.xy)
-
-            x.append(intr_x[:-1])
-            y.append(intr_y[:-1])
-
-        return x, y
-
     @classmethod
     def add_shape(cls, figure: Figure, shape: Union[str, BaseGeometry], **style_kwargs: Dict[str, Any]) -> None:
 
@@ -65,3 +38,32 @@ def add_shape(cls, figure: Figure, shape: Union[str, BaseGeometry], **style_kwar
         elif isinstance(shape, Polygon):
             x, y = cls._get_polygon_coords(shape)
             figure.multi_polygons([[x]], [[y]], **style_kwargs)
+
+    # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+    @classmethod
+    def _get_point_coords(cls, shape: Point) -> Tuple[float, float]:
+        return shape.x, shape.y
+
+    @classmethod
+    def _get_line_string_coords(cls, shape: Union[LineString, LinearRing]) -> Tuple[List[float], List[float]]:
+        x, y = map(list, shape.xy)
+        return x, y
+
+    @classmethod
+    def _get_polygon_coords(self, shape: Polygon) -> Tuple[List[List[float]], List[List[float]]]:
+
+        ext_x, ext_y = map(list, shape.exterior.xy)
+
+        # Shape coordinates start and end with the same value.
+        # Chop off last coordinate for Bokeh.
+        x: List[float] = [ext_x[:-1]]
+        y: List[float] = [ext_y[:-1]]
+
+        for intr_shape in shape.interiors:
+            intr_x, intr_y = map(list, intr_shape.xy)
+
+            x.append(intr_x[:-1])
+            y.append(intr_y[:-1])
+
+        return x, y

src/wktplot/plots/osm.py

@@ -2,18 +2,32 @@
 from bokeh.tile_providers import Vendors, get_provider
 from typing import Any, Dict
 from wktplot.mappers.osm import OpenStreetMapper
+from wktplot.mappers.standard import StandardMapper
 from wktplot.plots.standard import WKTPlot
 
 
 class OpenStreetMapsPlot(WKTPlot):
     """ OpenStreetMaps WKTPlot Bokeh wrapper class.
     """
 
-    mapper = OpenStreetMapper
-    default_figure_style_kwargs: Dict[str, str] = {
-        "x_axis_type": "mercator",
-        "y_axis_type": "mercator",
-    }
+    def __init__(self, *args, disable_mercator: bool = False, **kwargs) -> None:
+        """ Create figure with given arguments.
+
+        Args:
+            title (str): Title for graph and output filename, defaults to random string if unset.
+            save_dir (str | obj: Path | None, default = None): Optional path to save output file to.
+            disable_mercator (bool, default=False): Disable mercator proction calculation for shape data.
+            **figure_style_kwargs (dict[str, Any]): Dictionary of attributes to style the created figure.
+                See this guide for available style attributes:
+                https://docs.bokeh.org/en/2.4.3/docs/reference/plotting/figure.html
+
+        Raises:
+            ValueError: If value for `title` is not a string or None.
+            OSError: If value for `save_dir` is not a directory.
+        """
+
+        super().__init__(*args, **kwargs)
+        self.mapper = StandardMapper if disable_mercator else OpenStreetMapper
 
     @classmethod
     def _create_figure(cls, title: str, **style_kwargs: Dict[str, Any]) -> plt.Figure:
@@ -22,7 +36,8 @@ def _create_figure(cls, title: str, **style_kwargs: Dict[str, Any]) -> plt.Figur
         # - https://docs.bokeh.org/en/latest/docs/user_guide/geo.html#tile-provider-maps
         default_kwargs: Dict[str, Any] = {
             **style_kwargs,
-            **cls.default_figure_style_kwargs,
+            "x_axis_type": "mercator",
+            "y_axis_type": "mercator",
         }
 
         tile_provider = get_provider(Vendors.OSM)

src/wktplot/plots/standard.py

@@ -1,7 +1,7 @@
 from bokeh import plotting as plt
 from pathlib import Path
 from shapely.geometry.base import BaseGeometry
-from typing import Any, Dict, Optional, Union
+from typing import Any, Dict, Union
 from wktplot.common.file_utils import get_random_string, sanitize_text
 from wktplot.mappers.standard import StandardMapper
 from wktplot.plots.base import BasePlot
@@ -11,23 +11,17 @@ class WKTPlot(BasePlot):
     """ Standard WKTPlot Bokeh wrapper class.
     """
 
-    mapper = StandardMapper
-    default_figure_style_kwargs: Dict[str, str] = {
-        "x_axis_label": "Longitude",
-        "y_axis_label": "Latitude",
-    }
-
     def __init__(
         self,
         title: str = get_random_string(),
-        save_dir: Optional[Union[str, Path]] = None,
+        save_dir: Union[str, Path] = Path("."),
         **figure_style_kwargs: Dict[str, Any],
     ) -> None:
         """ Create figure with given arguments.
 
         Args:
             title (str): Title for graph and output filename, defaults to random string if unset.
-            save_dir (str | obj: Path | None, default = None): Optional path to save output file to.
+            save_dir (str | obj: Path, default = "."): Optional path to save output file to.
             **figure_style_kwargs (dict[str, Any]): Dictionary of attributes to style the created figure.
                 See this guide for available style attributes:
                 https://docs.bokeh.org/en/2.4.3/docs/reference/plotting/figure.html
@@ -40,36 +34,39 @@ def __init__(
         if not isinstance(title, str):
             raise ValueError(f"Given argument `title` is not a string. [{title}]")
 
-        if save_dir is not None:
-            if isinstance(save_dir, str):
-                save_dir = Path(save_dir)
+        if isinstance(save_dir, str):
+            save_dir = Path(save_dir)
 
-            if not (isinstance(save_dir, Path) and save_dir.is_dir()):
-                raise OSError(f"Given argument `save_dir` is not a directory. [{save_dir}]")
+        if not (isinstance(save_dir, Path) and save_dir.is_dir()):
+            raise OSError(f"Given argument `save_dir` is not a directory. [{save_dir}]")
 
-            filename: Path = save_dir / f"{sanitize_text(title)}.html"
-            plt.output_file(filename=filename, title=title, mode="inline")
+        filename: Path = save_dir / f"{sanitize_text(title)}.html"
+        plt.output_file(filename=filename, title=title, mode="inline")
 
         self.figure: plt.Figure = self._create_figure(title=title, **figure_style_kwargs)
+        self.mapper = StandardMapper
+
+    def add_shape(self, shape: Union[str, BaseGeometry], **style_kwargs: dict) -> None:
+        self.mapper.add_shape(self.figure, shape, **style_kwargs)
+
+    def save(self) -> None:
+        plt.save(self.figure)
+
+    def show(self) -> None:
+        plt.show(self.figure)
+
+    # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
     @classmethod
     def _create_figure(cls, title: str, **style_kwargs: Dict[str, Any]) -> plt.Figure:
 
         default_kwargs: Dict[str, Any] = {
-            **cls.default_figure_style_kwargs,
+            "x_axis_label": "Longitude",
+            "y_axis_label": "Latitude",
             **style_kwargs,
         }
 
         fig = plt.figure(title=title, **default_kwargs)
         fig.toolbar.autohide = True
 
         return fig
-
-    def save(self) -> None:
-        plt.save(self.figure)
-
-    def show(self) -> None:
-        plt.show(self.figure)
-
-    def add_shape(self, shape: Union[str, BaseGeometry], **style_kwargs: dict) -> None:
-        self.mapper.add_shape(self.figure, shape, **style_kwargs)