How to save certain ogrinfo results to a variable?-CodePudding

I am using gdal's ogrinfo command in Python to obtain information about a shapefile.

My code is as follows:

from subprocess import Popen, PIPE


args = ['ogrinfo', '-ro', '-so', '-al', 'C:/test/test_shapefile.shp']
process = Popen(args, stdout=PIPE, stderr=PIPE)

stdout = process.communicate()[0].decode('utf-8').strip()
print(stdout)

In turn, this gives me a large amount of information e.g.

Layer name: test_shapefile
Metadata:
  DBF_DATE_LAST_UPDATE=2022-04-13
Geometry: 3D Point
Feature Count: 28915413
Extent: (317044.250000, 681703.750000) - (322287.250000, 685053.250000)
Layer SRS WKT:
PROJCRS["OSGB 1936 / British National Grid",
    BASEGEOGCRS["OSGB 1936",
        DATUM["OSGB 1936",
            ELLIPSOID["Airy 1830",6377563.396,299.3249646,
                LENGTHUNIT["metre",1]]],
        PRIMEM["Greenwich",0,
            ANGLEUNIT["degree",0.0174532925199433]],
        ID["EPSG",4277]],
    CONVERSION["British National Grid",
        METHOD["Transverse Mercator",
            ID["EPSG",9807]],
        PARAMETER["Latitude of natural origin",49,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8801]],
        PARAMETER["Longitude of natural origin",-2,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8802]],
        PARAMETER["Scale factor at natural origin",0.9996012717,
            SCALEUNIT["unity",1],
            ID["EPSG",8805]],
        PARAMETER["False easting",400000,
            LENGTHUNIT["metre",1],
            ID["EPSG",8806]],
        PARAMETER["False northing",-100000,
            LENGTHUNIT["metre",1],
            ID["EPSG",8807]]],
    CS[Cartesian,2],
        AXIS["(E)",east,
            ORDER[1],
            LENGTHUNIT["metre",1]],
        AXIS["(N)",north,
            ORDER[2],
            LENGTHUNIT["metre",1]],
    USAGE[
        SCOPE["Engineering survey, topographic mapping."],
        AREA["United Kingdom (UK) - offshore to boundary of UKCS within 49°45'N to 61°N and 9°W to 2°E; onshore Great Britain (England, Wales and Scotland). Isle of Man onshore."],
        BBOX[49.75,-9,61.01,2.01]],
    ID["EPSG",27700]]
Data axis to CRS axis mapping: 1,2
X: Real (24.15)
Y: Real (24.15)
Z: Real (24.15)

I'm wondering, is there any way to store certain information as a variable?

For example:

one_extent = 317044.250000, 322287.250000
second_extent = 681703.750000, 685053.250000
epsg = 4277

CodePudding user response：

If you need only the extent and the EPSG, you do not need OGRInfo, you can just use Python OGR and OSR bindings:

from osgeo import ogr, osr
import os

inShapefile = "C:/test/test_shapefile.shp"
inDriver = ogr.GetDriverByName("ESRI Shapefile")
inDataSource = inDriver.Open(inShapefile, 0)
inLayer = inDataSource.GetLayer()
extent = inLayer.GetExtent()

proj = osr.SpatialReference(wkt=inDataSource.GetProjection())
proj.AutoIdentifyEPSG()
epsg = proj.GetAttrValue('AUTHORITY',1)

print(f"extent: {extent} EPSG: {epsg}")