- add example usage in the README

- simplify model classes:
 - remove separate WGS84BoundingBox class, and replace BasicCoverage.wgs84_bbox with lon and lat Axis attributes
 - remove separate GridBoundingBox class, and change FullCoverage.grid_bbox to a BoundingBox object with None crs
 - remove the Crs class, replace all crs attributes to contain only the string as parsed from the WCS server
 - add a utility Crs class that allows to convert a CRS identifier to shorthand notation
 - change fields in RangeType from a dict to a list of Field objects
 - add __getitem__ methods to RangeType and BoundingBox for easier access to the fields/axes
- automate service tests

Author: misev

README.md

@@ -1,3 +1,5 @@
+from docutils.nodes import description
+
 # Overview
 
 The [OGC Web Coverage Service (WCS) standard](https://www.ogc.org/standards/wcs)
@@ -13,22 +15,195 @@ given WCS endpoint.
 
 # Examples
 
+The example below illustrates how to get a list of 
+[BasicCoverage](autoapi/wcs/model/index.html#wcs.model.BasicCoverage)
+objects for all coverages on the server, and extract various details
+for a particular coverage.
+
 ```python
 from wcs.service import WebCoverageService
+from wcs.model import Crs
 
 wcs_endpoint = "https://ows.rasdaman.org/rasdaman/ows"
 service = WebCoverageService(wcs_endpoint)
 
 # get a list of all coverages, with basic information such
 # as a WGS 84 bounding box and a native bounding box
 coverages = service.list_coverages()
+
+# get the AvgLandTemp coverage object, see BasicCoverage
+# in the API reference
 avg_land_temp = coverages['AvgLandTemp']
 
+# print all information
+print(avg_land_temp)
+
+# AvgLandTemp:
+#   subtype: ReferenceableGridCoverage
+#   native CRS: OGC:AnsiDate+EPSG:4326
+#   geo bbox:
+#     ansi:
+#       min: "2000-02-01"
+#       max: "2015-06-01"
+#       crs: OGC:AnsiDate
+#     Lat:
+#       min: -90
+#       max: 90
+#       crs: EPSG:4326
+#     Lon:
+#       min: -180
+#       max: 180
+#       crs: EPSG:4326
+#   lon/lat bbox:
+#     Lon:
+#       min: -180
+#       max: 180
+#       crs: EPSG:4326
+#     Lat:
+#       min: -90
+#       max: 90
+#       crs: EPSG:4326
+#   size in bytes: 4809618404
+
+# coverage subtype
+print(avg_land_temp.subtype)
+# ReferenceableGridCoverage
+
+# coverage bounding box, containing the CRS and axes
+bbox = avg_land_temp.bbox
+
+# full coverage crs identifier
+print(bbox.crs)
+# https://www.opengis.net/def/crs-compound?
+# 1=https://www.opengis.net/def/crs/OGC/0/AnsiDate&
+# 2=https://www.opengis.net/def/crs/EPSG/0/4326
+
+# coverage crs identifier in shorthand notation
+print(Crs.to_short_notation(bbox.crs))
+# OGC:AnsiDate+EPSG:4326
+
+# get information for the first axis; as it is a temporal axis,
+# the lower_bound and upper_bound are datetime.datetime objects.
+axis = bbox[0]
+name = axis.name
+lower_bound = axis.low
+upper_bound = axis.high
+print(f'{name}({lower_bound} - {upper_bound})')
+# ansi(2000-02-01 00:00:00+00:00 - 2015-06-01 00:00:00+00:00)
+
+# get information for the Lat axis
+axis = bbox['Lat']
+print(axis.name)
+# Lat
+
+# get size in bytes if available
+if avg_land_temp.size_bytes is not None:
+    print(avg_land_temp.size_bytes)
+    # 4809618404
+
+```
+
+The above example gets basic information about the coverage
+through what is published in the WCS GetCapabilities response.
+More detailed information can be retrieved with the 
+`list_full_info` method, which returns a
+[FullCoverage](autoapi/wcs/model/index.html#wcs.model.FullCoverage)
+object.
+
+```python
+from wcs.service import WebCoverageService
+
+wcs_endpoint = "https://ows.rasdaman.org/rasdaman/ows"
+service = WebCoverageService(wcs_endpoint)
+
 # get full information for a particular coverage by
 # parsing its DescribeCoverage document from the WCS server
 full_avg_land_temp = service.list_full_info('AvgLandTemp')
+
+# print all information
+print(full_avg_land_temp)
+
+# AvgLandTemp:
+#   native CRS: OGC:AnsiDate+EPSG:4326
+#   geo bbox:
+#     ansi:
+#       min: "2000-02-01"
+#       max: "2015-06-01"
+#       crs: OGC:AnsiDate
+#       uom: d
+#       type: irregular
+#       coefficients: ["2000-02-01", "2000-03-01", ...
+#                      "2015-05-01", "2015-06-01"]
+#     Lat:
+#       min: -90
+#       max: 90
+#       crs: EPSG:4326
+#       uom: degree
+#       resolution: -0.1
+#       type: regular
+#     Lon:
+#       min: -180
+#       max: 180
+#       crs: EPSG:4326
+#       uom: degree
+#       resolution: 0.1
+#       type: regular
+#   grid bbox:
+#     i:
+#       min: 0
+#       max: 184
+#       resolution: 1
+#       type: regular
+#     j:
+#       min: 0
+#       max: 1799
+#       resolution: 1
+#       type: regular
+#     k:
+#       min: 0
+#       max: 3599
+#       resolution: 1
+#       type: regular
+#   range type fields:
+#     Gray:
+#       type: Quantity
+#       label: Gray
+#       definition: http://www.opengis.net/def/dataType/OGC/0/float32
+#       nil values: 99999
+#       uom: 10^0
+#   metadata:
+#     {
+#       "covMetadata": null
+#     }
+
+
+# In addition to the geo bounding box in native CRS, the 
+# `FullCoverage` object also has a `grid_bbox`, which contains 
+# the integer grid axis bounds of the coverage. This is the same 
+# type of `BoundingBox` object, except the `crs` is None.
+print(full_avg_land_temp.grid_bbox)
+
+# The range_type indicates the structure of the cell values
+# of the coverage. It contains a `fields` attribute, which is
+# a list of `Field` object corresponding to the bands of the 
+# coverage. Check the documentation of RangeType for full details.
+range_type = full_avg_land_temp.range_type
+all_fields = range_type.fields
+field = range_type['Gray']  # or range_type[0]
+
+# get all properties of the field
+label = field.label
+description = field.description
+definition = field.definition
+nil_values = field.nil_values
+if field.is_quantity:
+  uom = field.uom
+else:
+  codespace = field.codespace
 ```
 
+
+
 # Contributing
 
 The directory structure is as follows:

tests/__init__.py

@@ -0,0 +1 @@
+"""Unit tests that should be executed with pytest."""