Eigener Prozess in Python¶
http://pywps.wald.intevation.org/documentation/process.html
Prozess ist einer Python-Klasse mit zwei Methoden:
- __init__()
- Initialization
- execute()
- Eigener Aufruf
exampleBufferProcess:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 | from pywps.Process.Process import WPSProcess
class Process(WPSProcess):
"""Main process class"""
def __init__(self):
"""Process initialization"""
# init process
WPSProcess.__init__(self,
identifier = "exampleBufferProcess",
title="Buffer",
version = "0.2",
storeSupported = "true",
statusSupported = "true",
abstract="Create a buffer around an input vector file",
grassLocation = True)
# process inputs
# complex input
self.dataIn = self.addComplexInput(identifier="data",
title = "Input data",
# some optional parameters
abstract="Input data in GML format", # default is empty
metadata=[{"foo":"bar"}], # default is empty
formats=[{"mimeType":"text/xml"}], # default value
maxOccurs=1, # default value
maxmegabites="5") # default maximum size
# string input
self.widthIn = self.addLiteralInput(identifier = "width",
title = "Width",abstract="buffer width",
maxOccurs=3)
# bbox input
self.bboxIn = self.addBBoxInput(identifier = "bbox",
title = "Bounding box for buffering",minOccurs=0)
# process outputs
# complex output
self.bufferOut = self.addComplexOutput(identifier="buffer",
title="Output buffer file")
# literal output
self.textOut = self.addLiteralOutput(identifier="text",
title="Just some literal output")
# bbox output
self.bboxOut = self.addBBoxOutput(identifier="bbox",
title="Resulting bbox")
def execute(self):
"""Execute process.
Each command will be executed and output values will be set
"""
# run some command from the command line
self.cmd(["g.region","-d"])
# import data
self.status.set("Importing data",20)
out = self.cmd(["v.in.ogr","-o","dsn=%s" % (self.getInputValue('data')),"output=data"])
self.cmd(["g.region","vect=data"])
# buffer
self.status.set("Buffering",50)
self.cmd(["v.buffer","input=data","output=data_buff","distance=%s"%self.widthIn.getValue()[0],
"scale=1.0","tolerance=0.01"])
# vector -> raster
self.status.set("Vector to raster conversion",70)
if self.bboxIn.minx == None:
self.cmd(["g.region","vect=data_buff"])
else:
self.cmd(["g.region",
"e=%s" % self.bboxIn.minx,
"s=%s" % self.bboxIn.miny,
"w=%s" % self.bboxIn.maxx,
"n=%s" % self.bboxIn.maxx])
self.cmd(["v.to.rast","use=cat","input=data_buff","output=buff","type=area"])
# export
self.status.set("Exporting data",90)
self.cmd(["v.out.ogr","type=area","format=GML","input=data_buff","dsn=out.xml","olayer=path.xml"])
north = south = east = west = 0
for l in self.cmd(["v.info","-g","data_buff"]).split("\n"):
coord=l.split("=")
if coord[0] == "north":
north = coord[1]
elif coord[0] == "west":
west = coord[1]
elif coord[0] == "east":
east = coord[1]
elif coord[0] == "south":
south = coord[1]
self.bboxOut.setValue([west,south,east,north])
# setting output values
self.bufferOut.setValue("out.xml")
self.textOut.setValue("hallo, world")
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