Wrong pixel dimension after SRS assignment with pyqgis
I use pyQGIS (Python 2. with QGIS 2.18) to assign the same reference system to some raster files in .asc format (that came out without any SRS).
Each .asc file has 1m pixel dimension.
I use this pyqgis script to convert the raster in GeoTIFF and assigning the EPSG:3003.
It works but output files have a final resolution of 16.2 x 15.6.
How to preserve the original pixel dimension?
import os
import processing
from qgis.core import *
raster_filepath = "/home/giacomo/Desktop/Livorno/QGIS/Raster/DEM_Lidar/new/prova"
outputDir = "/home/giacomo/Desktop/Livorno/QGIS/Raster/DEM_Lidar/new/"
for i in os.listdir(raster_filepath):
if i.endswith (".asc"):
#name fileOut
ii = i[:-4]
fileOut = outputDir + "/" + ii + "_rep.tif"
layercount = os.path.join(raster_filepath, i)
raster_layer = QgsRasterLayer(layercount, 'raster')
# assessing the raster dimension
raster_extent = raster_layer.extent()
xmin = raster_extent.xMinimum()
xmax = raster_extent.xMaximum()
ymin = raster_extent.yMinimum()
ymax = raster_extent.yMaximum()
# processing
processing.runalg("gdalogr:translate",
{"INPUT":raster_layer,
"OUTSIZE":100,
"OUTSIZE_PERC":False,
"EXPAND":0,
"PROJWIN": "%f,%f,%f,%f"%(xmin,xmax,ymin,ymax),
"SRS":"EPSG:3003",
"OUTPUT":fileOut})
print(fileOut)
qgis pyqgis
edited Dec 31 '18 at 13:02
Vince
14.8k32749
asked Dec 31 '18 at 12:09
ilFontailFonta
498311
add a comment |
I use pyQGIS (Python 2. with QGIS 2.18) to assign the same reference system to some raster files in .asc format (that came out without any SRS).
Each .asc file has 1m pixel dimension.
I use this pyqgis script to convert the raster in GeoTIFF and assigning the EPSG:3003.
It works but output files have a final resolution of 16.2 x 15.6.
How to preserve the original pixel dimension?
import os
import processing
from qgis.core import *
raster_filepath = "/home/giacomo/Desktop/Livorno/QGIS/Raster/DEM_Lidar/new/prova"
outputDir = "/home/giacomo/Desktop/Livorno/QGIS/Raster/DEM_Lidar/new/"
for i in os.listdir(raster_filepath):
if i.endswith (".asc"):
#name fileOut
ii = i[:-4]
fileOut = outputDir + "/" + ii + "_rep.tif"
layercount = os.path.join(raster_filepath, i)
raster_layer = QgsRasterLayer(layercount, 'raster')
# assessing the raster dimension
raster_extent = raster_layer.extent()
xmin = raster_extent.xMinimum()
xmax = raster_extent.xMaximum()
ymin = raster_extent.yMinimum()
ymax = raster_extent.yMaximum()
# processing
processing.runalg("gdalogr:translate",
{"INPUT":raster_layer,
"OUTSIZE":100,
"OUTSIZE_PERC":False,
"EXPAND":0,
"PROJWIN": "%f,%f,%f,%f"%(xmin,xmax,ymin,ymax),
"SRS":"EPSG:3003",
"OUTPUT":fileOut})
print(fileOut)
qgis pyqgis
edited Dec 31 '18 at 13:02
Vince
14.8k32749
asked Dec 31 '18 at 12:09
ilFontailFonta
498311
add a comment |
I use pyQGIS (Python 2. with QGIS 2.18) to assign the same reference system to some raster files in .asc format (that came out without any SRS).
Each .asc file has 1m pixel dimension.
I use this pyqgis script to convert the raster in GeoTIFF and assigning the EPSG:3003.
It works but output files have a final resolution of 16.2 x 15.6.
How to preserve the original pixel dimension?
import os
import processing
from qgis.core import *
raster_filepath = "/home/giacomo/Desktop/Livorno/QGIS/Raster/DEM_Lidar/new/prova"
outputDir = "/home/giacomo/Desktop/Livorno/QGIS/Raster/DEM_Lidar/new/"
for i in os.listdir(raster_filepath):
if i.endswith (".asc"):
#name fileOut
ii = i[:-4]
fileOut = outputDir + "/" + ii + "_rep.tif"
layercount = os.path.join(raster_filepath, i)
raster_layer = QgsRasterLayer(layercount, 'raster')
# assessing the raster dimension
raster_extent = raster_layer.extent()
xmin = raster_extent.xMinimum()
xmax = raster_extent.xMaximum()
ymin = raster_extent.yMinimum()
ymax = raster_extent.yMaximum()
# processing
processing.runalg("gdalogr:translate",
{"INPUT":raster_layer,
"OUTSIZE":100,
"OUTSIZE_PERC":False,
"EXPAND":0,
"PROJWIN": "%f,%f,%f,%f"%(xmin,xmax,ymin,ymax),
"SRS":"EPSG:3003",
"OUTPUT":fileOut})
print(fileOut)
qgis pyqgis
edited Dec 31 '18 at 13:02
Vince
14.8k32749
asked Dec 31 '18 at 12:09
ilFontailFonta
498311
I use pyQGIS (Python 2. with QGIS 2.18) to assign the same reference system to some raster files in .asc format (that came out without any SRS).
Each .asc file has 1m pixel dimension.
I use this pyqgis script to convert the raster in GeoTIFF and assigning the EPSG:3003.
It works but output files have a final resolution of 16.2 x 15.6.
How to preserve the original pixel dimension?
import os
import processing
from qgis.core import *
raster_filepath = "/home/giacomo/Desktop/Livorno/QGIS/Raster/DEM_Lidar/new/prova"
outputDir = "/home/giacomo/Desktop/Livorno/QGIS/Raster/DEM_Lidar/new/"
for i in os.listdir(raster_filepath):
if i.endswith (".asc"):
#name fileOut
ii = i[:-4]
fileOut = outputDir + "/" + ii + "_rep.tif"
layercount = os.path.join(raster_filepath, i)
raster_layer = QgsRasterLayer(layercount, 'raster')
# assessing the raster dimension
raster_extent = raster_layer.extent()
xmin = raster_extent.xMinimum()
xmax = raster_extent.xMaximum()
ymin = raster_extent.yMinimum()
ymax = raster_extent.yMaximum()
# processing
processing.runalg("gdalogr:translate",
{"INPUT":raster_layer,
"OUTSIZE":100,
"OUTSIZE_PERC":False,
"EXPAND":0,
"PROJWIN": "%f,%f,%f,%f"%(xmin,xmax,ymin,ymax),
"SRS":"EPSG:3003",
"OUTPUT":fileOut})
print(fileOut)
qgis pyqgis
qgis pyqgis
edited Dec 31 '18 at 13:02
Vince
14.8k32749
asked Dec 31 '18 at 12:09
ilFontailFonta
498311
edited Dec 31 '18 at 13:02
Vince
14.8k32749
asked Dec 31 '18 at 12:09
ilFontailFonta
498311
edited Dec 31 '18 at 13:02
Vince
14.8k32749
edited Dec 31 '18 at 13:02
Vince
14.8k32749
edited Dec 31 '18 at 13:02
Vince
14.8k32749
14.8k32749
asked Dec 31 '18 at 12:09
ilFontailFonta
498311
asked Dec 31 '18 at 12:09
ilFontailFonta
498311
asked Dec 31 '18 at 12:09
ilFontailFonta
498311
498311
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
Normally I would do this on the command line but you should be able to do it in python too.
I would simply use gdal_translate -a_srs epsg:3003 file.asc file.tif - there should be no need to specify a projwin or outsize and I suspect that is where things are going wrong, it seems likely that the raster_extent is being interpreted wrongly as you have no projection set at that point.
answered Dec 31 '18 at 12:20
Ian Turton♦Ian Turton
50k547116
You are right. I mean: I still used the gdalogr processing from the python shell in QGIS, but just deleting the OUTSIZE and OUTSIZE_PERC from my script was sufficient to preserve the raster resolution. Thanks
– ilFonta
Dec 31 '18 at 13:02
add a comment |
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1 Answer
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1 Answer
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oldest
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votes
Normally I would do this on the command line but you should be able to do it in python too.
I would simply use gdal_translate -a_srs epsg:3003 file.asc file.tif - there should be no need to specify a projwin or outsize and I suspect that is where things are going wrong, it seems likely that the raster_extent is being interpreted wrongly as you have no projection set at that point.
answered Dec 31 '18 at 12:20
Ian Turton♦Ian Turton
50k547116
You are right. I mean: I still used the gdalogr processing from the python shell in QGIS, but just deleting the OUTSIZE and OUTSIZE_PERC from my script was sufficient to preserve the raster resolution. Thanks
– ilFonta
Dec 31 '18 at 13:02
add a comment |
Normally I would do this on the command line but you should be able to do it in python too.
I would simply use gdal_translate -a_srs epsg:3003 file.asc file.tif - there should be no need to specify a projwin or outsize and I suspect that is where things are going wrong, it seems likely that the raster_extent is being interpreted wrongly as you have no projection set at that point.
answered Dec 31 '18 at 12:20
Ian Turton♦Ian Turton
50k547116
You are right. I mean: I still used the gdalogr processing from the python shell in QGIS, but just deleting the OUTSIZE and OUTSIZE_PERC from my script was sufficient to preserve the raster resolution. Thanks
– ilFonta
Dec 31 '18 at 13:02
add a comment |
Normally I would do this on the command line but you should be able to do it in python too.
I would simply use gdal_translate -a_srs epsg:3003 file.asc file.tif - there should be no need to specify a projwin or outsize and I suspect that is where things are going wrong, it seems likely that the raster_extent is being interpreted wrongly as you have no projection set at that point.
answered Dec 31 '18 at 12:20
Ian Turton♦Ian Turton
50k547116
Normally I would do this on the command line but you should be able to do it in python too.
I would simply use gdal_translate -a_srs epsg:3003 file.asc file.tif - there should be no need to specify a projwin or outsize and I suspect that is where things are going wrong, it seems likely that the raster_extent is being interpreted wrongly as you have no projection set at that point.
answered Dec 31 '18 at 12:20
Ian Turton♦Ian Turton
50k547116
answered Dec 31 '18 at 12:20
Ian Turton♦Ian Turton
50k547116
answered Dec 31 '18 at 12:20
Ian Turton♦Ian Turton
50k547116
answered Dec 31 '18 at 12:20
Ian Turton♦Ian Turton
50k547116
50k547116
You are right. I mean: I still used the gdalogr processing from the python shell in QGIS, but just deleting the OUTSIZE and OUTSIZE_PERC from my script was sufficient to preserve the raster resolution. Thanks
– ilFonta
Dec 31 '18 at 13:02
add a comment |
You are right. I mean: I still used the gdalogr processing from the python shell in QGIS, but just deleting the OUTSIZE and OUTSIZE_PERC from my script was sufficient to preserve the raster resolution. Thanks
– ilFonta
Dec 31 '18 at 13:02
You are right. I mean: I still used the gdalogr processing from the python shell in QGIS, but just deleting the OUTSIZE and OUTSIZE_PERC from my script was sufficient to preserve the raster resolution. Thanks
– ilFonta
Dec 31 '18 at 13:02
You are right. I mean: I still used the gdalogr processing from the python shell in QGIS, but just deleting the OUTSIZE and OUTSIZE_PERC from my script was sufficient to preserve the raster resolution. Thanks
– ilFonta
Dec 31 '18 at 13:02
add a comment |
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