[Qgis-user] Issues with QgsCoordinateTransform - SOLVED

[Tudorache, Marian]

I think I figured out.
First mistake: replace datum with ellps so the InternalCrsIdfor=100006 is: +proj=longlat +ellps=GRS80 +no_defs
Second Mistake:
Longitude that I use is 114 25 15.88 W'. Wrong. The longitude cannot be greater than 90 degree.
I changed the  longitude in range and it did work.

Any tip will be welcome.

Thanks,
Marian

-----Original Message-----
From: Tudorache, Marian
Sent: September-09-15 2:44 PM
To: 'qgis-user at lists.osgeo.org'
Subject: RE: Issues with QgsCoordinateTransform

Sorry the copy paste did not work well so I put the script uncleaned.
Here is the script again. The issue is the same: transformation from la/long to X / Y does not work.


 ######################################################
import processing, sys, os, math, LatLon, pyproj from PyQt4 import QtCore crsScr  = QgsCoordinateReferenceSystem(100006, QgsCoordinateReferenceSystem.InternalCrsId)
crsDest = QgsCoordinateReferenceSystem(100000, QgsCoordinateReferenceSystem.InternalCrsId)
xform = QgsCoordinateTransform(crsScr, crsDest)

coord_start = '53 30 21.88 N, 114 25 15.88 W'
coord_end = '54 40 21.88 N, 115 30 15.88 W'
start_Point = coord_start.split(',')
end_Point = coord_end.split(',')
start_Line = LatLon.string2latlon(str(start_Point[0]).strip(), str(start_Point[1]).strip(), 'd% %m% %S% %H') end_Line = LatLon.string2latlon(str(end_Point[0]).strip(), str(end_Point[1]).strip(), 'd% %m% %S% %H') print "QgsPoint = ",QgsPoint(float(start_Line.to_string()[0]), float(start_Line.to_string()[1]))

line_start = QgsPoint(float(start_Line.to_string()[0]), float(start_Line.to_string()[1])) line_end = QgsPoint(float(end_Line.to_string()[0]), float(end_Line.to_string()[1]))

pointGeomStart = QgsGeometry.fromPoint(line_start) pointGeomEnd = QgsGeometry.fromPoint(line_end)

print "Geometry points Start = {0}, End = {1}".format(pointGeomStart.asPoint(), pointGeomEnd.asPoint())

print "QgsCoordinateTransform.ReverseTransform = ",xform.transform(pointGeomStart.asPoint(), QgsCoordinateTransform.ReverseTransform)
print "QgsCoordinateTransform.ForwardTransform = ",xform.transform(pointGeomStart.asPoint(), QgsCoordinateTransform.ForwardTransform)
#####################################################################################################

The InternalCrsIdfor=100006 is: +proj=longlat +datum=GRS80 +no_defs The InternalCrsIdfor=100000 is: +proj=sterea +lat_0=53.5 +lon_0=-76.0 +k=1 +x_0=0 +y_0=0 +a=6381816.160744 +b=6381816.160744 +units=m +no_defs

I try to transform the coordinate '53 30 21.88 N, 114 25 15.88 W' and '54 40 21.88 N, 115 30 15.88 W' from 100006 to 100000

This is the output
QgsPoint =  (53.5061,-114.421)
Geometry points Start = (53.5061,-114.421),

End = (54.6727,-115.504)

QgsCoordinateTransform.ReverseTransform =  (53.5061,-114.421)

QgsCoordinateTransform.ForwardTransform =  (53.5061,-114.421)


Basically there is no diference between ReverseTransform and ForwardTransform. I am expecting to get X=-2549670.6 and Y=678.9 or (-2549670.6,678.9) when I am doing forward transformation.


Any idea what is wrong?

Thanks,
Marian

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