WCPS ProcessCoverages implementation

examples/wcps-processcoverage.py

@@ -0,0 +1,46 @@
+# Very simple script demonstrating the use ProcessCoverages request making use WCPS.
+# ---
+#
+# The equivalent ProcessCoverage request that is equivalent ot hte example is:
+# https://code-de.rasdaman.com/rasdaman/ows?service=WCS&version=2.0.1&request=ProcessCoverages&query=for%20%24c%20in%20(S2_L2A_32631_B01_60m)%20%0Areturn%0A%20%20encode(%0A%20%20%20%20(%200.20%20*%20(%201050.0%20%2B%20(%20%0A%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20(float)%20%24c%5B%20ansi(%20%222017-04-03%22%20)%20%5D%20-%20%0A%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%24c%5B%20ansi(%20%222017-04-10%22%20)%20%5D%20)%20%0A%20%20%20%20%20%20%20%20%20%20%20%20)%20%0A%20%20%20%20)%5B%20E(%20660000%3A690000%20)%2C%20N(%205090220%3A5115220%20)%20%5D%0A%20%20%20%2C%20%22image%2Fjpeg%22)%0A%27%27%27
+# ---
+# 
+# Example to find the equivalent information using OWSLib is as below:
+# 
+
+from owslib.wcs import WebCoverageService
+import numpy as np
+from io import BytesIO
+from PIL import Image as im
+
+my_wcs = WebCoverageService('https://code-de.rasdaman.com/rasdaman/ows', version='2.0.1')
+
+#query performs time-series processing by calculating, in the Sentinel-2 datacube,
+#the difference between two timeslices of the B1 band. The result is numerically
+#adjusted so that it fits into the range of [0, 255] for encoding in JPEG
+query = '''
+for $c in (S2_L2A_32631_B01_60m)
+return
+  encode(
+    ( 0.20 * ( 1050.0 + (
+                (float) $c[ ansi( "2017-04-03" ) ] -
+                        $c[ ansi( "2017-04-10" ) ] )
+            )
+    )[ E( 660000:690000 ), N( 5090220:5115220 ) ]
+   , "image/jpeg")
+'''
+
+
+response = my_wcs.process(query)
+
+#bytes -> BytesIO -> PIL.Image -> np.array
+img_arr = np.array(im.open(BytesIO(response)))
+
+#image being extracted from image array
+data = im.fromarray(img_arr)
+
+#showing image
+data.show()
+
+#saving image as a jpeg file
+data.save('test.jpeg')

owslib/coverage/wcps.py

@@ -0,0 +1,49 @@
+from urllib.parse import quote, urlencode
+from owslib.util import Authentication, openURL
+
+class ProcessCoverages(object):
+    """Sends the encoded WCPS query to WCS server by using "ProcessCoverage" operation
+    """
+
+    def __init__(self, version=None, cookies=None, auth=None, headers=None):
+
+        self.version = version
+        self._infoset = None
+        self.cookies = cookies
+        self.headers = headers
+        self.auth = auth or Authentication()
+
+     #get/kvp encoding implementation
+    def getKVPUrl(self, service_url, query):
+        """Return a process coverage url encoded in get/kvp
+        @type service_url: string
+        @param service_url: base url of WCS service
+        @rtype: string
+        @return: processCoverage URL
+        """
+        url = []
+        url.append(('service', 'WCS'))
+        url.append(('request', 'ProcessCoverages'))
+        url.append(('version', '2.0'))
+        url.append(('query', ""))
+
+        urlqs = urlencode(tuple(url))
+
+        return service_url.split('?')[0] + '?' + urlqs + query
+
+
+    def process(self, service_url, query):
+        """Get and process a WCPS query result, returning the
+        result in encode() format
+
+        @type service_url: string
+        @param service_url: The base url, to which is appended the service,
+        version, and request parameters
+        @param query: WCPS that needs to be processed
+        @rtype: response content
+        @return: encoded coverage
+        """
+        query = quote(query) # encoding the query parameter
+        request = ProcessCoverages.getKVPUrl(self, service_url=service_url, query=query)
+        u = openURL(request, timeout=self.timeout, cookies=self.cookies, auth=self.auth, headers=self.headers)
+        return u.read()

owslib/coverage/wcs201.py

@@ -19,7 +19,7 @@
     ServiceProvider,
     OperationsMetadata,
 )
-
+from owslib.coverage.wcps import ProcessCoverages
 from urllib.parse import urlencode
 from owslib.util import openURL, testXMLValue
 from owslib.etree import etree
@@ -226,6 +226,10 @@ def getOperationByName(self, name):
                 return item
         raise KeyError("No operation named %s" % name)
 
+    #WCS ProcessCoverages implementation
+    def process(self,query):
+        result = ProcessCoverages.process(self, service_url=self.url, query=query)
+        return result
 
 class ContentMetadata(object):
     """