Extract coordinate system,projection names for files listed in a csv using gdal/python

Question

We have 1000's of files for which projection/datum/geocs/projcs names has to be extracted. This code reads the filename listed in the csv.

from os import path
from osgeo import gdal,osr
import csv
csvpath = r"D:\\Test\\QGISPRJ.csv"
csvdir = path.split(csvpath)[0]
with open(csvpath, "r") as csvfile:
    fcs = [r[0] for r in csv.reader(csvfile)]
    for ds in fcs:
        print ds

Output:
E:\Santiago_Low\SourceData\Chile Projects\spectrem\Area2\Area2_AEM_x7.TIF
E:\Santiago_Low\SourceData\_South America Regional\233_080_Si_15m_321comp.ECW
E:\Santiago_Low\SourceData\Inactive Projects\ASTER_VNIR_orthoRGB_PSAD56_19S.TIF
E:\Santiago_Low_Priority\SourceData\Chile Projects\Explora_KRIP_Res.TIF

But, if i use getProjection() in the code - as mentioned in this thread - GDAL/Python: How do I get coordinate system name from SpatialReference? - i am getting this error

from os import path
from osgeo import gdal,osr
import csv
csvpath = r"D:\\Test\\QGISPRJ.csv"
csvdir = path.split(csvpath)[0]
with open(csvpath, "r") as csvfile:
    fcs = [r[0] for r in csv.reader(csvfile)]
    for ds in fcs:
        prj=ds.GetProjection()
        srs=osr.SpatialReference(wkt=prj)
        print srs.GetAttrValue('projcs')
        print srs.GetAttrValue('geogcs')
        print srs.GetAttrValue('Datum')
        print srs.GetAttrValue('Projection')

Traceback (most recent call last):
File "<input>", line 4, in <module>
AttributeError: 'str' object has no attribute 'GetProjection'

But if i run the same code without the csv file as an input and use the filename directly it works fine.

from osgeo import gdal,osr
ds=gdal.Open(r'E:\\Santiago_Low\\SourceData\\Chile Projects\\Ground POS EM\\Mapinfo\\300mSlice_Image.TIF')
prj=ds.GetProjection()
print prj
srs=osr.SpatialReference(wkt=prj)
print srs.GetAttrValue('projcs')
print srs.GetAttrValue('geogcs')

Since i am very much a beginner as far as Python is concerned, i don't know how to proceed.I've read this gdal/python: extracting projection info from hdf file and few other questions w.r.t 'str' object has no attribute error in python. But still couldn't able to figure out what's wrong.

Answer 1

The attribute error is because ds is a string, and not a GDAL dataset.

It can be fixed by referencing the file name string in the for loop, then opening the dataset:

for fname in fcs:
    ds = gdal.Open(fname)