Add multiple rasters using QgsRasterLayer with for loop

Question

I am trying to create a for loop for coloring up multiple rasters simultaneously. I am able to do it for one layer, but trying to implement the for loop to do it for more than one layer is proving difficult.

import glob,os

rast_path="/home/user/Desktop/data/gsi/output"
rasters=glob.glob(os.path.join(rast_path,"*le.tif"))
print(rasters)

for raster in rasters:
#    (rastdir,rastfile)=os.path.split(raster)
    lyr=QgsRasterLayer(rasters,rastfile)
    s=QgsRasterShader()
    c=QgsColorRampShader()
    c.setColorRampType(QgsColorRampShader.INTERPOLATED)
    i=[]
    i.append(QgsColorRampShader.ColorRampItem(-20,QtGui.QColor('#0c0101'),'-20'))
    i.append(QgsColorRampShader.ColorRampItem(-15.1,QtGui.QColor('#ff0000'),'-15'))
    i.append(QgsColorRampShader.ColorRampItem(-10,QtGui.QColor('#ff0000'),'-10'))
    i.append(QgsColorRampShader.ColorRampItem(-5,QtGui.QColor('#ff0000'),'-5'))
    i.append(QgsColorRampShader.ColorRampItem(0,QtGui.QColor('#ff0000'),'0'))
    i.append(QgsColorRampShader.ColorRampItem(5,QtGui.QColor('#ff0000'),'5'))
    i.append(QgsColorRampShader.ColorRampItem(10,QtGui.QColor('#ff0000'),'10'))
    i.append(QgsColorRampShader.ColorRampItem(15,QtGui.QColor('#ff0000'),'15'))
    i.append(QgsColorRampShader.ColorRampItem(15,QtGui.QColor('#0c0101'),'20'))
    c.setColorRampItemList(i)
    s.setRasterShaderFunction(c)

    ps=QgsSingleBandPseudoColorRenderer(lyr.dataProvider(),1,s)
    raster.setRenderer(ps)
    QgsMapLayerRegistry.instance().addMapLayer(lyr)
#    qgis.utils.iface.addRasterLayer(raster,rastfile)

Answer 1

I prefer adding rasters described from the QGIS docs which I've incorporated into your script in addition to importing a couple more required classes:

import glob, os
from PyQt4 import QtGui
from PyQt4.QtCore import QFileInfo

rast_path = "/home/user/Desktop/data/gsi/output"
rasters = glob.glob(os.path.join(rast_path, "*le.tif"))
print(rasters)

for raster in rasters:
    fileInfo = QFileInfo(raster)
    path = fileInfo.filePath()
    baseName = fileInfo.baseName()
    lyr = QgsRasterLayer(path, baseName)
    s = QgsRasterShader()
    c = QgsColorRampShader()
    c.setColorRampType(QgsColorRampShader.INTERPOLATED)
    i = []
    i.append(QgsColorRampShader.ColorRampItem(-20,QtGui.QColor('#0c0101'),'-20'))
    i.append(QgsColorRampShader.ColorRampItem(-15.1,QtGui.QColor('#ff0000'),'-15'))
    i.append(QgsColorRampShader.ColorRampItem(-10,QtGui.QColor('#ff0000'),'-10'))
    i.append(QgsColorRampShader.ColorRampItem(-5,QtGui.QColor('#ff0000'),'-5'))
    i.append(QgsColorRampShader.ColorRampItem(0,QtGui.QColor('#ff0000'),'0'))
    i.append(QgsColorRampShader.ColorRampItem(5,QtGui.QColor('#ff0000'),'5'))
    i.append(QgsColorRampShader.ColorRampItem(10,QtGui.QColor('#ff0000'),'10'))
    i.append(QgsColorRampShader.ColorRampItem(15,QtGui.QColor('#ff0000'),'15'))
    i.append(QgsColorRampShader.ColorRampItem(15,QtGui.QColor('#0c0101'),'20'))
    c.setColorRampItemList(i)
    s.setRasterShaderFunction(c)
    ps = QgsSingleBandPseudoColorRenderer(lyr.dataProvider(),1,s)
    lyr.setRenderer(ps)
    QgsMapLayerRegistry.instance().addMapLayer(lyr)