Skip to content

Instantly share code, notes, and snippets.

@ThomasG77
Last active September 12, 2022 04:33
Show Gist options
  • Save ThomasG77/7c2ecd106091a335a2138dcd82565db8 to your computer and use it in GitHub Desktop.
Save ThomasG77/7c2ecd106091a335a2138dcd82565db8 to your computer and use it in GitHub Desktop.
Add this script in startup.py to now see zoom for EPSG 3857 when the canevas is using it
from math import cos, log, pi
from qgis.utils import iface
from qgis.PyQt.QtWidgets import QLabel
# Not needed here but could be useful later
# def getScale(zoom_level, screen_dpi=96, latitude=0):
# resolution = (6378137.0 * 2 * pi / 256) * cos(latitude) / (2**zoom_level)
# return (screen_dpi * 1/0.0254 * resolution)
def getZoomLevel(scale, screen_dpi=96, latitude=0):
resolution = scale / (screen_dpi * 1/0.0254)
zoom_level = ((6378137.0 * 2 * pi / 256) * cos(latitude)) / resolution
return log(zoom_level)/log(2)
canvas = iface.mapCanvas()
labelZoomNumberEpsg3857 = QLabel()
iface.mainWindow().statusBar().addPermanentWidget(labelZoomNumberEpsg3857)
def changeZoomNumberOsm(scale):
rounded_zoom_level = round(getZoomLevel(scale), 2)
labelZoomNumberEpsg3857.setText("Zoom level : {}".format(str(rounded_zoom_level)))
canvas.scaleChanged.connect(changeZoomNumberOsm)
def showHideZoomLevel():
if canvas.mapSettings().destinationCrs().authid() == "EPSG:3857":
labelZoomNumberEpsg3857.show()
else:
labelZoomNumberEpsg3857.hide()
canvas.destinationCrsChanged.connect(showHideZoomLevel)
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment