Python extension method for geotrellis_catalog

Signed-off-by: Jason T. Brown <[email protected]>

Author: vpipkt

pyrasterframes/src/main/python/docs/raster-read.pymd

@@ -193,7 +193,7 @@ mb2.printSchema()
 A GeoTrellis catalog is a set of GeoTrellis layers. We can read a dataframe giving details of the content of a catalog using the following. The scheme is typically `hdfs` or a cloud storage provider like `s3` or `wasb`.
 
 ```python, evaluate=False
-gt_cat = spark.read.format('geotrellis-catalog').load('scheme://path-to-gt-catalog')
+gt_cat = spark.read.geotrellis_catalog('scheme://path-to-gt-catalog')
 ```
 
 ### GeoTrellis Layers

pyrasterframes/src/main/python/pyrasterframes/__init__.py

@@ -223,4 +223,5 @@ def set_dims(parts):
 DataFrameReader.geotiff = lambda df_reader, path: _layer_reader(df_reader, "geotiff", path)
 DataFrameWriter.geotiff = _geotiff_writer
 DataFrameReader.geotrellis = lambda df_reader, path: _layer_reader(df_reader, "geotrellis", path)
+DataFrameReader.geotrellis_catalog = lambda df_reader, path: _aliased_reader(df_reader, "geotrellis-catalog", path)
 DataFrameWriter.geotrellis = lambda df_writer, path: _aliased_writer(df_writer, "geotrellis", path)