mirror of
https://github.com/wassname/PyCRS.git
synced 2026-06-27 16:10:29 +08:00
Karim Bahgat
fcc463fa76
Also just need to expand to more projection name, datum name, and ellipsoid name definitions, and also additional special parameters. After that, test, and move onto from_wkt()...
261 lines
7.9 KiB
Python
261 lines
7.9 KiB
Python
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# parse from text strings
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# possible use module: https://github.com/rockdoc/grabbag/wiki/CRS-WKT-Parser
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# also note some paramter descriptions: http://www.geoapi.org/3.0/javadoc/org/opengis/referencing/doc-files/WKT.html
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# and see gdal source code: http://gis.stackexchange.com/questions/129764/how-are-esri-wkt-projections-different-from-ogc-wkt-projections
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from . import datums
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from . import ellipsoids
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from . import parameters
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from . import units
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from . import projections
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def from_epsg_code(string):
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# must go online (or look up local table) to get crs details
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pass
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def from_esri_code(string):
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# must go online (or look up local table) to get crs details
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pass
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def from_sr_code(string):
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# must go online (or look up local table) to get crs details
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pass
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def from_esri_wkt(string):
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# parse arguments into components
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# use args to create crs
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pass
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def from_ogc_wkt(string):
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# parse arguments into components
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# use args to create crs
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pass
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def from_unknown_wkt(string):
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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):
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# parse arguments into components
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# use args to create crs
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## proj=robin +lon_0=0 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs
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##
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## PROJCS["World_Robinson",
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## GEOGCS["GCS_WGS_1984",
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## DATUM["WGS_1984",
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## SPHEROID["WGS_1984",6378137,298.257223563]],
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## PRIMEM["Greenwich",0],
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## UNIT["Degree",0.017453292519943295]],
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## PROJECTION["Robinson"],
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## PARAMETER["False_Easting",0],
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## PARAMETER["False_Northing",0],
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## PARAMETER["Central_Meridian",0],
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## UNIT["Meter",1],
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## AUTHORITY["EPSG","54030"]]
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params = []
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partdict = dict([part.split("=") for part in string.split()
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if not part.startswith("+no_defs")])
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# DATUM
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# datum param is required
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if "+datum" in partdict:
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# get predefined datum def
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if partdict["+datum"] == "WGS84":
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datumdef = datums.WGS84()
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# ELLIPS
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# ellipse param is required
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if "+ellps" in partdict:
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# get predefined ellips def
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if partdict["+ellps"] == "WGS84":
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ellipsdef = ellipsoids.WGS84()
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else:
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raise Exception("Could not find required +ellps element")
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## create datum and ellips param objs
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ellips = parameters.Ellipsoid(ellipsdef,
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semimaj_ax=partdict.get("+a"),
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inv_flat=partdict.get("+f"))
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datum = parameters.Datum(datumdef, ellips)
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else:
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raise Exception("Could not find required +datum element")
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# PRIME MERIDIAN
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# set default
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prime_mer = parameters.PrimeMeridian(0)
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# overwrite with user input
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if "+pm" in partdict:
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# for now only support longitude, later add name support:
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## greenwich 0dE
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## lisbon 9d07'54.862"W
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## paris 2d20'14.025"E
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## bogota 74d04'51.3"E
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## madrid 3d41'16.48"W
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## rome 12d27'8.4"E
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## bern 7d26'22.5"E
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## jakarta 106d48'27.79"E
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## ferro 17d40'W
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## brussels 4d22'4.71"E
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## stockholm 18d3'29.8"E
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## athens 23d42'58.815"E
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## oslo 10d43'22.5"E
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prime_mer = parameters.PrimeMeridian(partdict["+pm"])
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# ANGULAR UNIT
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## proj4 cannot set angular unit, so just set to default
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metmulti = parameters.MeterMultiplier(0.017453292519943295)
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unittype = parameters.UnitType(units.Degree())
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angunit = parameters.AngularUnit(unittype, metmulti)
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# GEOGCS (note, currently does not load axes)
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geogcs = parameters.GeogCS("Unknown", datum, prime_mer, angunit) #, twin_ax)
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# PROJECTION
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if "+proj" in partdict:
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# get predefined proj def
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if partdict["+proj"] == "robin":
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projdef = projections.Robinson()
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elif partdict["+proj"] == "longlat":
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projdef = None
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# set geogcs axis in correct order
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elif partdict["+proj"] == "latlong":
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projdef = None
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# set geogcs axis in correct order
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# ALSO SHOULDNT EXCLUDE +proj, NEED WAY TO INCLUDE IT...
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# ...
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else:
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projdef = None
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else:
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raise Exception("Could not find required +proj element")
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if projdef:
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# create proj param obj
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proj = parameters.Projection(projdef)
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# CENTRAL MERIDIAN
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if "+lon_0" in partdict:
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val = partdict["+lon_0"]
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obj = parameters.CentralMeridian(val)
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params.append(obj)
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# FALSE EASTING
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if "+x_0" in partdict:
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val = partdict["+x_0"]
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obj = parameters.FalseEasting(val)
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params.append(obj)
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# FALSE NORTHING
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if "+y_0" in partdict:
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val = partdict["+y_0"]
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obj = parameters.FalseNorthing(val)
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params.append(obj)
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# UNIT
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## set default
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metmulti = parameters.MeterMultiplier(1.0)
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unittype = parameters.UnitType(units.Meter())
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## override with user input
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if "+to_meter" in partdict:
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metmulti = parameters.MeterMultiplier(partdict["+to_meter"])
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if "+units" in partdict:
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if partdict["+units"] == "m":
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unittype = parameters.UnitType(units.Meter())
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## create unitobj
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unit = parameters.Unit(unittype, metmulti)
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# PROJCS
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projcs = parameters.ProjCS("Unknown", geogcs, proj, params, unit)
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# CRS
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crs = parameters.CRS(projcs)
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else:
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crs = parameters.CRS(geogcs)
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# FINISHED
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return crs
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def from_ogc_urn(string):
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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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# examples urn:ogc:def:crs:OGC:1.3:CRS1
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# or with EPSG instead of OGC
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# If OGC, 1.3 is pdf version, and after that is a name from list below
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# as found in pdf: "Definition identifier URNs in OGC namespace"
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# OGC crs definitions
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# URN | CRS name | Definition reference
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# urn:ogc:def:crs:OGC:1.3:CRS1 Map CS B.2 in OGC 06-042
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# urn:ogc:def:crs:OGC:1.3:CRS84 WGS 84 longitude-latitude B.3 in OGC 06-042
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# urn:ogc:def:crs:OGC:1.3:CRS83 NAD83 longitude-latitude B.4 in OGC 06-042
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# urn:ogc:def:crs:OGC:1.3:CRS27 NAD27 longitude-latitude B.5 in OGC 06-042
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# urn:ogc:def:crs:OGC:1.3:CRS88 NAVD 88 B.6 in OGC 06-042
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# urn:ogc:def:crs:OGC:1.3:AUTO42001:99:8888 Auto universal transverse mercator B.7 in OGC 06-042
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# urn:ogc:def:crs:OGC:1.3:AUTO42002:99:8888 Auto transverse mercator B.8 in OGC 06-042
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# urn:ogc:def:crs:OGC:1.3:AUTO42003:99:8888 Auto orthographic B.9 in OGC 06-042
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# urn:ogc:def:crs:OGC:1.3:AUTO42004:99:8888 Auto equirectangular B.10 in OGC 06-042
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# urn:ogc:def:crs:OGC:1.3:AUTO42005:99 Auto Mollweide B.11 in OGC 06-042
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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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if string.startswith("urn:"):
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from_ogc_urn(string)
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elif string.startswith("+proj="):
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from_proj4(string)
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elif string.startswith("PROJCS["):
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from_unknown_wkt(string)
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elif string.startswith("EPSG:"):
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from_epsg_code(string)
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elif string.startswith("ESRI:"):
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from_esri_code(string)
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elif string.startswith("SR-ORG:"):
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from_sr_code(string)
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else: raise Exception("Could not detect which type of crs")
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def from_geotiff_parameters(**params):
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pass
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