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Basic fromproj4 works, except need better handle when unprojected (longlat and latlong)

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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()...
This commit is contained in:
Karim Bahgat
2015-06-29 03:29:02 +02:00
parent 5a46702471
commit fcc463fa76
24 changed files with 502 additions and 130 deletions
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pycrs/parser.py
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# parse from text strings
# possible use module: https://github.com/rockdoc/grabbag/wiki/CRS-WKT-Parser
# also note some paramter descriptions: http://www.geoapi.org/3.0/javadoc/org/opengis/referencing/doc-files/WKT.html
# and see gdal source code: http://gis.stackexchange.com/questions/129764/how-are-esri-wkt-projections-different-from-ogc-wkt-projections
from . import datums
from . import ellipsoids
from . import parameters
from . import units
from . import projections
def from_epsg_code(string):
# must go online (or look up local table) to get crs details
pass
def from_esri_code(string):
# must go online (or look up local table) to get crs details
pass
def from_sr_code(string):
# must go online (or look up local table) to get crs details
pass
def from_esri_wkt(string):
# parse arguments into components
# use args to create crs
pass
def from_ogc_wkt(string):
# parse arguments into components
# use args to create crs
pass
def from_unknown_wkt(string):
# detect if ogc wkt or esri wkt
# TIPS: esri wkt datums all use "D_" before the datum name
# then load with appropriate function
pass
def from_proj4(string):
# parse arguments into components
# use args to create crs
## proj=robin +lon_0=0 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs
##
## PROJCS["World_Robinson",
## GEOGCS["GCS_WGS_1984",
## DATUM["WGS_1984",
## SPHEROID["WGS_1984",6378137,298.257223563]],
## PRIMEM["Greenwich",0],
## UNIT["Degree",0.017453292519943295]],
## PROJECTION["Robinson"],
## PARAMETER["False_Easting",0],
## PARAMETER["False_Northing",0],
## PARAMETER["Central_Meridian",0],
## UNIT["Meter",1],
## AUTHORITY["EPSG","54030"]]
params = []
partdict = dict([part.split("=") for part in string.split()
if not part.startswith("+no_defs")])
# DATUM
# datum param is required
if "+datum" in partdict:
# get predefined datum def
if partdict["+datum"] == "WGS84":
datumdef = datums.WGS84()
# ELLIPS
# ellipse param is required
if "+ellps" in partdict:
# get predefined ellips def
if partdict["+ellps"] == "WGS84":
ellipsdef = ellipsoids.WGS84()
else:
raise Exception("Could not find required +ellps element")
## create datum and ellips param objs
ellips = parameters.Ellipsoid(ellipsdef,
semimaj_ax=partdict.get("+a"),
inv_flat=partdict.get("+f"))
datum = parameters.Datum(datumdef, ellips)
else:
raise Exception("Could not find required +datum element")
# PRIME MERIDIAN
# set default
prime_mer = parameters.PrimeMeridian(0)
# overwrite with user input
if "+pm" in partdict:
# for now only support longitude, later add name support:
## greenwich 0dE
## lisbon 9d07'54.862"W
## paris 2d20'14.025"E
## bogota 74d04'51.3"E
## madrid 3d41'16.48"W
## rome 12d27'8.4"E
## bern 7d26'22.5"E
## jakarta 106d48'27.79"E
## ferro 17d40'W
## brussels 4d22'4.71"E
## stockholm 18d3'29.8"E
## athens 23d42'58.815"E
## oslo 10d43'22.5"E
prime_mer = parameters.PrimeMeridian(partdict["+pm"])
# ANGULAR UNIT
## proj4 cannot set angular unit, so just set to default
metmulti = parameters.MeterMultiplier(0.017453292519943295)
unittype = parameters.UnitType(units.Degree())
angunit = parameters.AngularUnit(unittype, metmulti)
# GEOGCS (note, currently does not load axes)
geogcs = parameters.GeogCS("Unknown", datum, prime_mer, angunit) #, twin_ax)
# PROJECTION
if "+proj" in partdict:
# get predefined proj def
if partdict["+proj"] == "robin":
projdef = projections.Robinson()
elif partdict["+proj"] == "longlat":
projdef = None
# set geogcs axis in correct order
elif partdict["+proj"] == "latlong":
projdef = None
# set geogcs axis in correct order
# ALSO SHOULDNT EXCLUDE +proj, NEED WAY TO INCLUDE IT...
# ...
else:
projdef = None
else:
raise Exception("Could not find required +proj element")
if projdef:
# create proj param obj
proj = parameters.Projection(projdef)
# CENTRAL MERIDIAN
if "+lon_0" in partdict:
val = partdict["+lon_0"]
obj = parameters.CentralMeridian(val)
params.append(obj)
# FALSE EASTING
if "+x_0" in partdict:
val = partdict["+x_0"]
obj = parameters.FalseEasting(val)
params.append(obj)
# FALSE NORTHING
if "+y_0" in partdict:
val = partdict["+y_0"]
obj = parameters.FalseNorthing(val)
params.append(obj)
# UNIT
## set default
metmulti = parameters.MeterMultiplier(1.0)
unittype = parameters.UnitType(units.Meter())
## override with user input
if "+to_meter" in partdict:
metmulti = parameters.MeterMultiplier(partdict["+to_meter"])
if "+units" in partdict:
if partdict["+units"] == "m":
unittype = parameters.UnitType(units.Meter())
## create unitobj
unit = parameters.Unit(unittype, metmulti)
# PROJCS
projcs = parameters.ProjCS("Unknown", geogcs, proj, params, unit)
# CRS
crs = parameters.CRS(projcs)
else:
crs = parameters.CRS(geogcs)
# FINISHED
return crs
def from_ogc_urn(string):
# hmmm, seems like ogc urn could be anything incl online link, epsg, etc...
# if necessary, must go online (or lookup local table) to get details
# maybe test which of these and run their function?
# examples urn:ogc:def:crs:OGC:1.3:CRS1
# or with EPSG instead of OGC
# If OGC, 1.3 is pdf version, and after that is a name from list below
# as found in pdf: "Definition identifier URNs in OGC namespace"
# OGC crs definitions
# URN | CRS name | Definition reference
# urn:ogc:def:crs:OGC:1.3:CRS1 Map CS B.2 in OGC 06-042
# urn:ogc:def:crs:OGC:1.3:CRS84 WGS 84 longitude-latitude B.3 in OGC 06-042
# urn:ogc:def:crs:OGC:1.3:CRS83 NAD83 longitude-latitude B.4 in OGC 06-042
# urn:ogc:def:crs:OGC:1.3:CRS27 NAD27 longitude-latitude B.5 in OGC 06-042
# urn:ogc:def:crs:OGC:1.3:CRS88 NAVD 88 B.6 in OGC 06-042
# urn:ogc:def:crs:OGC:1.3:AUTO42001:99:8888 Auto universal transverse mercator B.7 in OGC 06-042
# urn:ogc:def:crs:OGC:1.3:AUTO42002:99:8888 Auto transverse mercator B.8 in OGC 06-042
# urn:ogc:def:crs:OGC:1.3:AUTO42003:99:8888 Auto orthographic B.9 in OGC 06-042
# urn:ogc:def:crs:OGC:1.3:AUTO42004:99:8888 Auto equirectangular B.10 in OGC 06-042
# urn:ogc:def:crs:OGC:1.3:AUTO42005:99 Auto Mollweide B.11 in OGC 06-042
pass
def from_unknown_text(text):
# detect type and load with appropriate function
if string.startswith("urn:"):
from_ogc_urn(string)
elif string.startswith("+proj="):
from_proj4(string)
elif string.startswith("PROJCS["):
from_unknown_wkt(string)
elif string.startswith("EPSG:"):
from_epsg_code(string)
elif string.startswith("ESRI:"):
from_esri_code(string)
elif string.startswith("SR-ORG:"):
from_sr_code(string)
else: raise Exception("Could not detect which type of crs")
def from_geotiff_parameters(**params):
pass