使用GDAL从tif文件创建shapefile

Question

我正在使用一个叫做gdal的库来加载一个tiff文件，并创建一个shapefile（形状文件）。

当我用QGIS这个图形界面软件加载我的shapefile时，发现没有关于高度的信息。

我希望在转换的过程中能够保留高度信息。

import os
from osgeo import gdal,ogr,osr,gdalnumeric
import numpy as np

# this allows GDAL to throw Python Exceptions
gdal.UseExceptions()


print "reading tif file..."
try:
    ds = gdal.Open( "file.tif" )
except RuntimeError, e:
    print 'Unable to open file'
    print e
    sys.exit(1)

try:
    srcband = ds.GetRasterBand(1)
except RuntimeError, e:
    # for example, try GetRasterBand(10)
    print 'Band ( %i ) not found' % band_num
    print e
    sys.exit(1)


band = ds.GetRasterBand(1)
# elevation 2D numpy array
elevation = band.ReadAsArray()

# create shapefile datasource from geotiff file
#
print "creating shapefile..."
dst_layername = "Shape"
drv = ogr.GetDriverByName("ESRI Shapefile")
dst_ds = drv.CreateDataSource( dst_layername + ".shp" )
dst_layer = dst_ds.CreateLayer(dst_layername, srs = None )
gdal.Polygonize( srcband, None, dst_layer, -1, [], callback=None 

谢谢，

Answer 1

这是你的脚本，已经更新为创建一个叫做“elevation”的字段，并将第一波段的栅格值提取到这个字段中。

import os
from osgeo import gdal,ogr
import sys 

# mapping between gdal type and ogr field type
type_mapping = { gdal.GDT_Byte: ogr.OFTInteger,
                 gdal.GDT_UInt16: ogr.OFTInteger,   
                 gdal.GDT_Int16: ogr.OFTInteger,    
                 gdal.GDT_UInt32: ogr.OFTInteger,
                 gdal.GDT_Int32: ogr.OFTInteger,
                 gdal.GDT_Float32: ogr.OFTReal,
                 gdal.GDT_Float64: ogr.OFTReal,
                 gdal.GDT_CInt16: ogr.OFTInteger,
                 gdal.GDT_CInt32: ogr.OFTInteger,
                 gdal.GDT_CFloat32: ogr.OFTReal,
                 gdal.GDT_CFloat64: ogr.OFTReal}

# this allows GDAL to throw Python Exceptions
gdal.UseExceptions()


print "reading tif file..."
try:
    ds = gdal.Open(sys.argv[1])
except RuntimeError, e:
    print 'Unable to open file'
    print e
    sys.exit(1)

try:
    srcband = ds.GetRasterBand(1)
except RuntimeError, e:
    # for example, try GetRasterBand(10)
    print 'Band ( %i ) not found' % 1
    print e
    sys.exit(1)

# create shapefile datasource from geotiff file
print "creating shapefile..."
dst_layername = "Shape"
drv = ogr.GetDriverByName("ESRI Shapefile")
dst_ds = drv.CreateDataSource( "poly_out.shp" )
dst_layer = dst_ds.CreateLayer(dst_layername, srs = None )
raster_field = ogr.FieldDefn('elevation', type_mapping[srcband.DataType])
dst_layer.CreateField(raster_field)
gdal.Polygonize( srcband, None, dst_layer, 0, [], callback=None)