requires() decorator for libpysal.cg.alpha_shapes

[jGaboardi]

Is there a reason not to use the requires('geopandas') decorator for alpha_shape() and alpha_shape_auto(), rather than the following in alpha_geoms()?

    try:
        from shapely.geometry import LineString
        from shapely.ops import polygonize
    except ImportError:
        raise ImportError("Shapely is a required package to use alpha_shapes")

    try:
        from geopandas import GeoSeries
    except ImportError:
        raise ImportError("Geopandas is a required package to use alpha_shapes")

If geopandas is available, then a working install of shapely should also be available. However, to be on the safe side the function could be decorated with requires('geopandas', 'shapely')

---

• Platform information:
  posix darwin
  posix.uname_result(sysname='Darwin', nodename='The-Gaboardi.local', release='18.2.0', version='Darwin Kernel Version 18.2.0: Mon Nov 12 20:24:46 PST 2018; root:xnu-4903.231.4~2/RELEASE_X86_64', machine='x86_64')

• Python version:
  3.6.6 | packaged by conda-forge | (default, Jul 26 2018, 09:55:02)
  [GCC 4.2.1 Compatible Apple LLVM 6.1.0 (clang-602.0.53)]

• SciPy version:
  1.1.0

• NumPy version:
  1.14.3

[jGaboardi]

closed via #129