Update documentation

docs/chapters/faq.rst

@@ -47,6 +47,6 @@ the polygon (i.e. do not intersect the polygon's boundary). In that
 case, the output centerline can be reduced to a single line or even a
 single point.
 
-When the centerline consists of less than two lines, a ``RuntimeError``
+When the centerline consists of less than two lines, the ``TooFewRidgesError``
 is raised, the ``create_centerline`` script skips the geometry in
 question and continues processing the other geometries.

docs/chapters/usage.rst

@@ -14,8 +14,20 @@ This library provides the ``create_centerlines`` command-line script for creatin
 Python
 ======
 
-If you want to create your own scripts or use the ``Centerline`` class directly, you can import it:
+If you want to use the ``Centerline`` class directly, you can import it and instatiate it with geometric data (of type ``shapely.geometry.Polygon`` or ``shapely.geometry.MultiPolygon``) and the object's attributes (optional):
 
 .. code:: python
 
-    from centerline.geometry import Centerline
+    >>> from shapely.geometry import Polygon
+    >>> from centerline.geometry import Centerline
+
+    >>> polygon = Polygon([[0, 0], [0, 4], [4, 4], [4, 0]])
+    >>> attributes = {"id": 1, "name": "polygon", "valid": True}
+
+    >>> centerline = Centerline(polygon, **attributes)
+    >>> centerline.id == 1
+    True
+    >>> centerline.name
+    'polygon'
+    >>> centerline.geoms
+    <shapely.geometry.base.GeometrySequence object at 0x7f7d24116210>

docs/modules/centerline.rst

@@ -1,4 +1,4 @@
-centerline's API
+API
 ==================
 
 Module contents