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https://github.com/wassname/PyCRS.git
synced 2026-06-27 16:10:29 +08:00
Expanded on the various docstrings
This commit is contained in:
Karim Bahgat
@@ -11,6 +11,16 @@ from . import parser
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# convenience methods for loading from different sources
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def from_url(url, format=None):
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"""
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Returns the crs object from a string interpreted as a specified format, located at a given url site.
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Arguments:
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- *url*: The url where the crs string is to be read from.
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- *format*: Which format to parse the crs string as. One of "ogcwkt", "esriwkt", or "proj4", but also several others...
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Returns:
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- CRS object.
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"""
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# first get string from url
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string = urllib2.urlopen(url).read()
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@@ -28,6 +38,9 @@ def from_url(url, format=None):
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return crs
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def from_file(filepath):
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"""
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Returns the crs object from a file, with the format determined from the filename extension.
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"""
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if filepath.endswith(".prj"):
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string = open(filepath, "r").read()
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return parser.from_esri_wkt(string)
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Binary file not shown.
+138
-28
@@ -14,6 +14,16 @@ from . import projections
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from . import webscrape
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def from_epsg_code(code):
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"""
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Load crs object from epsg code, via spatialreference.org.
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Parses based on the proj4 representation.
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Arguments:
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- *code*: The EPSG code as an integer.
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Returns:
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- CRS object.
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"""
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# must go online (or look up local table) to get crs details
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code = str(code)
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proj4 = webscrape.crscode_to_string("epsg", code, "proj4")
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@@ -21,6 +31,16 @@ def from_epsg_code(code):
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return crs
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def from_esri_code(code):
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"""
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Load crs object from esri code, via spatialreference.org.
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Parses based on the proj4 representation.
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Arguments:
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- *code*: The ESRI code as an integer.
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Returns:
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- CRS object.
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"""
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# must go online (or look up local table) to get crs details
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code = str(code)
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proj4 = webscrape.crscode_to_string("esri", code, "proj4")
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@@ -28,6 +48,16 @@ def from_esri_code(code):
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return crs
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def from_sr_code(code):
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"""
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Load crs object from sr-org code, via spatialreference.org.
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Parses based on the proj4 representation.
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Arguments:
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- *code*: The SR-ORG code as an integer.
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Returns:
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- CRS object.
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"""
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# must go online (or look up local table) to get crs details
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code = str(code)
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proj4 = webscrape.crscode_to_string("sr-org", code, "proj4")
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@@ -35,21 +65,53 @@ def from_sr_code(code):
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return crs
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def from_ogc_wkt(string, strict=False):
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"""
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Parse crs as ogc wkt formatted string and return the resulting crs object.
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Arguments:
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- *string*: The OGC WKT representation as a string.
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- *strict* (optional): When True, the parser is strict about names having to match
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exactly with upper and lowercases. Default is not strict (False).
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Returns:
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- CRS object.
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"""
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# parse arguments into components
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# use args to create crs
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return _from_wkt(string, "ogc", strict)
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def from_esri_wkt(string, strict=False):
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"""
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Parse crs as esri wkt formatted string and return the resulting crs object.
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Arguments:
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- *string*: The ESRI WKT representation as a string.
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- *strict* (optional): When True, the parser is strict about names having to match
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exactly with upper and lowercases. Default is not strict (False).
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Returns:
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- CRS object.
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"""
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# parse arguments into components
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# use args to create crs
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return _from_wkt(string, "esri", strict)
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def _from_wkt(string, wkttype, strict=False):
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"""
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Internal method for parsing wkt, with minor differences depending on ogc or esri style.
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Arguments:
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- *string*: The OGC or ESRI WKT representation as a string.
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- *wkttype*: How to parse the WKT string, as either 'ogc' or 'esri'.
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- *strict* (optional): When True, the parser is strict about names having to match
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exactly with upper and lowercases. Default is not strict (False).
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Returns:
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- CRS object.
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"""
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# TODO
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# - Make try except search loops into a reusable function
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# - Make function for finding next elemt by name, instead of knowing its arg index position
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# - Maybe verify elem arg name
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# - Convert all param and name values to lowercase so not so strict...
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# make sure valid wkttype
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wkttype = wkttype.lower()
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@@ -162,6 +224,7 @@ def _from_wkt(string, wkttype, strict=False):
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# parse into actual crs objects
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def _parse_top(header, content):
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"procedure for parsing the toplevel crs element and all its children"
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if header.upper() == "PROJCS":
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# find name
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@@ -174,8 +237,12 @@ def _from_wkt(string, wkttype, strict=False):
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# find projection elem
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subheader, subcontent = content[2]
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projname = subcontent[0].strip('"')
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projdef = projections.find(projname, "%s_wkt" % wkttype, strict)()
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proj = parameters.Projection(projdef)
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projclass = projections.find(projname, "%s_wkt" % wkttype, strict)
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if projclass:
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projdef = projclass()
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proj = parameters.Projection(projdef)
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else:
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raise Exception("The specified projection name could not be found")
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# find params
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params = []
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@@ -230,9 +297,13 @@ def _from_wkt(string, wkttype, strict=False):
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if subheader == "UNIT":
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break
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unitname,value = subcontent[0].strip('"'), subcontent[1]
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unit = units.find(unitname, "%s_wkt" % wkttype, strict)()
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if unit:
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unitclass = units.find(unitname, "%s_wkt" % wkttype, strict)
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if unitclass:
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unit = unitclass()
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unittype = parameters.UnitType(unit)
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else:
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raise Exception("The specified unit name could not be found")
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## if subcontent[0].strip('"') == "Meters":
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## unittype = parameters.UnitType(units.Meter())
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## elif subcontent[0].strip('"') == "degree":
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@@ -259,14 +330,21 @@ def _from_wkt(string, wkttype, strict=False):
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## datum name
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datumname = subcontent[0].strip('"')
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datumdef = datums.find(datumname, "%s_wkt" % wkttype, strict)()
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if not datumdef:
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datumclass = datums.find(datumname, "%s_wkt" % wkttype, strict)
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if datumclass:
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datumdef = datumclass()
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else:
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datumdef = datums.Unknown()
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## datum ellipsoid
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subsubheader, subsubcontent = subcontent[1]
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ellipsname = subsubcontent[0].strip('"')
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ellipsdef = ellipsoids.find(ellipsname, "%s_wkt" % wkttype, strict)()
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ellipsclass = ellipsoids.find(ellipsname, "%s_wkt" % wkttype, strict)
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if ellipsclass:
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ellipsdef = ellipsclass()
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else:
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raise Exception("The specified ellipsoid name could not be found")
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ellipsoid = parameters.Ellipsoid(ellipsdef, subsubcontent[1], subsubcontent[2])
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## datum shift
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@@ -290,9 +368,12 @@ def _from_wkt(string, wkttype, strict=False):
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# angunit
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subheader, subcontent = content[3]
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unitname,value = subcontent[0].strip('"'), subcontent[1]
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unit = units.find(unitname, "%s_wkt" % wkttype, strict)()
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if unit:
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unitclass = units.find(unitname, "%s_wkt" % wkttype, strict)
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if unitclass:
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unit = unitclass()
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unittype = parameters.UnitType(unit)
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else:
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raise Exception("The specified unit name could not be found")
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## if subcontent[0].strip('"') == "Meters":
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## unittype = parameters.UnitType(units.Meter())
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## elif subcontent[0].strip('"') == "degree":
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@@ -315,13 +396,24 @@ def _from_wkt(string, wkttype, strict=False):
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# use args to create crs
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return crs
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##def from_unknown_wkt(string):
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##def from_unknown_wkt(string, strict=False):
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## # detect if ogc wkt or esri wkt
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## # TIPS: esri wkt datums all use "D_" before the datum name
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## # then load with appropriate function
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## pass
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def from_proj4(string, strict=False):
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"""
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Parse crs as proj4 formatted string and return the resulting crs object.
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Arguments:
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- *string*: The proj4 representation as a string.
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- *strict* (optional): When True, the parser is strict about names having to match
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exactly with upper and lowercases. Default is not strict (False).
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Returns:
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- CRS object.
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"""
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# parse arguments into components
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# use args to create crs
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@@ -361,8 +453,10 @@ def from_proj4(string, strict=False):
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# get predefined datum def
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datumname = partdict["+datum"]
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datumdef = datums.find(datumname, "proj4", strict)()
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if not datumdef:
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datumclass = datums.find(datumname, "proj4", strict)
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if datumclass:
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datumdef = datumclass()
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else:
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datumdef = datums.Unknown()
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else:
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@@ -375,9 +469,12 @@ def from_proj4(string, strict=False):
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# get predefined ellips def
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ellipsname = partdict["+ellps"]
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ellipsdef = ellipsoids.find(ellipsname, "proj4", strict)()
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if not ellipsdef:
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raise Exception("The ellipsoid name did not match any definitions")
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ellipsclass = ellipsoids.find(ellipsname, "proj4", strict)
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if ellipsclass:
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ellipsdef = ellipsclass
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else:
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raise Exception("The specified ellipsoid name could not be found")
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else:
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raise Exception("Could not find required +ellps element")
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@@ -452,7 +549,7 @@ def from_proj4(string, strict=False):
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# proj4 special case, longlat as projection name means unprojected geogcs
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projdef = None
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else:
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raise Exception("The specified +proj name could not be found")
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raise Exception("The specified projection name could not be found")
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else:
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raise Exception("Could not find required +proj element")
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@@ -563,9 +660,12 @@ def from_proj4(string, strict=False):
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metmulti = parameters.MeterMultiplier(partdict["+to_meter"])
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if "+units" in partdict:
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unitname = partdict["+units"]
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unit = units.find(unitname, "proj4", strict)()
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if unit:
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unitclass = units.find(unitname, "proj4", strict)
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if unitclass:
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unit = unitclass()
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unittype = parameters.UnitType(unit)
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else:
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raise Exception("The specified unit name could not be found")
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## create unitobj
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unit = parameters.Unit(unittype, metmulti)
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@@ -587,7 +687,7 @@ def from_proj4(string, strict=False):
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return crs
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##def from_ogc_urn(string):
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##def from_ogc_urn(string, strict=False):
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## # hmmm, seems like ogc urn could be anything incl online link, epsg, etc...
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## # if necessary, must go online (or lookup local table) to get details
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## # maybe test which of these and run their function?
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@@ -612,17 +712,27 @@ def from_proj4(string, strict=False):
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## pass
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def from_unknown_text(text):
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"""Detect type and load with appropriate function"""
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def from_unknown_text(text, strict=False):
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"""
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Detect crs string format and parse into crs object with appropriate function.
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Arguments:
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- *string*: The crs text representation of unknown type.
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- *strict* (optional): When True, the parser is strict about names having to match
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exactly with upper and lowercases. Default is not strict (False).
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Returns:
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- CRS object.
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"""
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if string.startswith("urn:"):
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from_ogc_urn(string)
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from_ogc_urn(string, strict)
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elif string.startswith("+proj="):
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from_proj4(string)
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elif string.startswith("+"):
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from_proj4(string, strict)
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elif string.startswith("PROJCS["):
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from_unknown_wkt(string)
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elif string.startswith(("PROJCS[","GEOGCS[")):
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from_unknown_wkt(string, strict)
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elif string.startswith("EPSG:"):
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from_epsg_code(string.split(":")[1])
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Binary file not shown.
+4
-3
@@ -61,9 +61,10 @@ def crscode_to_string(codetype, code, format):
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"""
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Lookup crscode on spatialreference.org and return in specified format.
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- codetype: "epsg", "esri", or "sr-org"
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- code: The code
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- format: The crs format of the returned string. One of "ogcwkt", "esriwkt", or "proj4", but also several others...
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Arguments:
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- *codetype*: "epsg", "esri", or "sr-org".
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- *code*: The code.
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- *format*: The crs format of the returned string. One of "ogcwkt", "esriwkt", or "proj4", but also several others...
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"""
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link = 'http://spatialreference.org/ref/%s/%s/%s/' %(codetype,code,format)
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result = urllib2.urlopen(link).read()
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