本文整理汇总了Python中qgis.core.QgsCoordinateReferenceSystem.createFromSrsId方法的典型用法代码示例。如果您正苦于以下问题：Python QgsCoordinateReferenceSystem.createFromSrsId方法的具体用法？Python QgsCoordinateReferenceSystem.createFromSrsId怎么用？Python QgsCoordinateReferenceSystem.createFromSrsId使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类qgis.core.QgsCoordinateReferenceSystem的用法示例。
在下文中一共展示了QgsCoordinateReferenceSystem.createFromSrsId方法的3个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Python代码示例。
示例1: testLengthMeasureAndUnits
# 需要导入模块: from qgis.core import QgsCoordinateReferenceSystem [as 别名]
# 或者: from qgis.core.QgsCoordinateReferenceSystem import createFromSrsId [as 别名]
def testLengthMeasureAndUnits(self):
"""Test a variety of length measurements in different CRS and ellipsoid modes, to check that the
calculated lengths and units are always consistent
"""
da = QgsDistanceArea()
da.setSourceCrs(3452)
da.setEllipsoidalMode(False)
da.setEllipsoid("NONE")
daCRS = QgsCoordinateReferenceSystem()
daCRS.createFromSrsId(da.sourceCrs())
# We check both the measured length AND the units, in case the logic regarding
# ellipsoids and units changes in future
distance = da.measureLine(QgsPoint(1, 1), QgsPoint(2, 3))
units = da.lengthUnits()
print "measured {} in {}".format(distance, QgsUnitTypes.toString(units))
assert ((abs(distance - 2.23606797) < 0.00000001 and units == QGis.Degrees) or
(abs(distance - 248.52) < 0.01 and units == QGis.Meters))
da.setEllipsoid("WGS84")
distance = da.measureLine(QgsPoint(1, 1), QgsPoint(2, 3))
units = da.lengthUnits()
print "measured {} in {}".format(distance, QgsUnitTypes.toString(units))
assert ((abs(distance - 2.23606797) < 0.00000001 and units == QGis.Degrees) or
(abs(distance - 248.52) < 0.01 and units == QGis.Meters))
da.setEllipsoidalMode(True)
distance = da.measureLine(QgsPoint(1, 1), QgsPoint(2, 3))
units = da.lengthUnits()
print "measured {} in {}".format(distance, QgsUnitTypes.toString(units))
# should always be in Meters
self.assertAlmostEqual(distance, 247555.57, delta=0.01)
self.assertEqual(units, QGis.Meters)
# now try with a source CRS which is in feet
da.setSourceCrs(27469)
da.setEllipsoidalMode(False)
# measurement should be in feet
distance = da.measureLine(QgsPoint(1, 1), QgsPoint(2, 3))
units = da.lengthUnits()
print "measured {} in {}".format(distance, QgsUnitTypes.toString(units))
self.assertAlmostEqual(distance, 2.23606797, delta=0.000001)
self.assertEqual(units, QGis.Feet)
da.setEllipsoidalMode(True)
# now should be in Meters again
distance = da.measureLine(QgsPoint(1, 1), QgsPoint(2, 3))
units = da.lengthUnits()
print "measured {} in {}".format(distance, QgsUnitTypes.toString(units))
self.assertAlmostEqual(distance, 0.67953772, delta=0.000001)
self.assertEqual(units, QGis.Meters)示例2: browseCRS
# 需要导入模块: from qgis.core import QgsCoordinateReferenceSystem [as 别名]
# 或者: from qgis.core.QgsCoordinateReferenceSystem import createFromSrsId [as 别名]
def browseCRS(self):
selector = QgsGenericProjectionSelector()
selector.setSelectedAuthId(self.crs)
if selector.exec_():
authId = selector.selectedAuthId()
if authId.upper().startswith("EPSG:"):
self.crs = authId
else:
proj = QgsCoordinateReferenceSystem()
proj.createFromSrsId(selector.selectedCrsId())
self.crs = proj.toProj4()
self.updateText()示例3: testAreaMeasureAndUnits
# 需要导入模块: from qgis.core import QgsCoordinateReferenceSystem [as 别名]
# 或者: from qgis.core.QgsCoordinateReferenceSystem import createFromSrsId [as 别名]
def testAreaMeasureAndUnits(self):
"""Test a variety of area measurements in different CRS and ellipsoid modes, to check that the
calculated areas and units are always consistent
"""
da = QgsDistanceArea()
da.setSourceCrs(3452)
da.setEllipsoidalMode(False)
da.setEllipsoid("NONE")
daCRS = QgsCoordinateReferenceSystem()
daCRS.createFromSrsId(da.sourceCrs())
polygon = QgsGeometry.fromPolygon(
[[
QgsPoint(0, 0), QgsPoint(1, 0), QgsPoint(1, 1), QgsPoint(2, 1), QgsPoint(2, 2), QgsPoint(0, 2), QgsPoint(0, 0),
]]
)
# We check both the measured area AND the units, in case the logic regarding
# ellipsoids and units changes in future
area = da.measureArea(polygon)
units = da.areaUnits()
print("measured {} in {}".format(area, QgsUnitTypes.toString(units)))
assert ((abs(area - 3.0) < 0.00000001 and units == QgsUnitTypes.SquareDegrees) or
(abs(area - 37176087091.5) < 0.1 and units == QgsUnitTypes.SquareMeters))
da.setEllipsoid("WGS84")
area = da.measureArea(polygon)
units = da.areaUnits()
print("measured {} in {}".format(area, QgsUnitTypes.toString(units)))
assert ((abs(area - 3.0) < 0.00000001 and units == QgsUnitTypes.SquareDegrees) or
(abs(area - 37176087091.5) < 0.1 and units == QgsUnitTypes.SquareMeters))
da.setEllipsoidalMode(True)
area = da.measureArea(polygon)
units = da.areaUnits()
print("measured {} in {}".format(area, QgsUnitTypes.toString(units)))
# should always be in Meters Squared
self.assertAlmostEqual(area, 37416879192.9, delta=0.1)
self.assertEqual(units, QgsUnitTypes.SquareMeters)
# test converting the resultant area
area = da.convertAreaMeasurement(area, QgsUnitTypes.SquareMiles)
self.assertAlmostEqual(area, 14446.7378, delta=0.001)
# now try with a source CRS which is in feet
polygon = QgsGeometry.fromPolygon(
[[
QgsPoint(1850000, 4423000), QgsPoint(1851000, 4423000), QgsPoint(1851000, 4424000), QgsPoint(1852000, 4424000), QgsPoint(1852000, 4425000), QgsPoint(1851000, 4425000), QgsPoint(1850000, 4423000)
]]
)
da.setSourceCrs(27469)
da.setEllipsoidalMode(False)
# measurement should be in square feet
area = da.measureArea(polygon)
units = da.areaUnits()
print("measured {} in {}".format(area, QgsUnitTypes.toString(units)))
self.assertAlmostEqual(area, 2000000, delta=0.001)
self.assertEqual(units, QgsUnitTypes.SquareFeet)
# test converting the resultant area
area = da.convertAreaMeasurement(area, QgsUnitTypes.SquareYards)
self.assertAlmostEqual(area, 222222.2222, delta=0.001)
da.setEllipsoidalMode(True)
# now should be in Square Meters again
area = da.measureArea(polygon)
units = da.areaUnits()
print("measured {} in {}".format(area, QgsUnitTypes.toString(units)))
self.assertAlmostEqual(area, 184149.37, delta=1.0)
self.assertEqual(units, QgsUnitTypes.SquareMeters)
# test converting the resultant area
area = da.convertAreaMeasurement(area, QgsUnitTypes.SquareYards)
self.assertAlmostEqual(area, 220240.8172549, delta=1.0)