def createDistanceTransform(rasterSrc,
vectorSrc,
npDistFileName='',
units='pixels'):
## open source vector file that truth data
source_ds = ogr.Open(vectorSrc)
source_layer = source_ds.GetLayer()
## extract data from src Raster File to be emulated
## open raster file that is to be emulated
srcRas_ds = gdal.Open(rasterSrc)
cols = srcRas_ds.RasterXSize
rows = srcRas_ds.RasterYSize
noDataValue = 0
if units == 'meters':
geoTrans, poly, ulX, ulY, lrX, lrY = gT.getRasterExtent(srcRas_ds)
transform_WGS84_To_UTM, transform_UTM_To_WGS84, utm_cs = gT.createUTMTransform(
poly)
line = ogr.Geometry(ogr.wkbLineString)
line.AddPoint(geoTrans[0], geoTrans[3])
line.AddPoint(geoTrans[0] + geoTrans[1], geoTrans[3])
line.Transform(transform_WGS84_To_UTM)
metersIndex = line.Length()
else:
metersIndex = 1
## create First raster memory layer
memdrv = gdal.GetDriverByName('MEM')
dst_ds = memdrv.Create('', cols, rows, 1, gdal.GDT_Byte)
dst_ds.SetGeoTransform(srcRas_ds.GetGeoTransform())
dst_ds.SetProjection(srcRas_ds.GetProjection())
band = dst_ds.GetRasterBand(1)
band.SetNoDataValue(noDataValue)
gdal.RasterizeLayer(dst_ds, [1], source_layer, burn_values=[255])
srcBand = dst_ds.GetRasterBand(1)
memdrv2 = gdal.GetDriverByName('MEM')
prox_ds = memdrv2.Create('', cols, rows, 1, gdal.GDT_Int16)
prox_ds.SetGeoTransform(srcRas_ds.GetGeoTransform())
prox_ds.SetProjection(srcRas_ds.GetProjection())
proxBand = prox_ds.GetRasterBand(1)
proxBand.SetNoDataValue(noDataValue)
options = ['NODATA=0']
##compute distance to non-zero pixel values and scrBand and store in proxBand
gdal.ComputeProximity(srcBand, proxBand, options)
memdrv3 = gdal.GetDriverByName('MEM')
proxIn_ds = memdrv3.Create('', cols, rows, 1, gdal.GDT_Int16)
proxIn_ds.SetGeoTransform(srcRas_ds.GetGeoTransform())
proxIn_ds.SetProjection(srcRas_ds.GetProjection())
proxInBand = proxIn_ds.GetRasterBand(1)
proxInBand.SetNoDataValue(noDataValue)
options = ['NODATA=0', 'VALUES=0']
##compute distance to zero pixel values and scrBand and store in proxInBand
gdal.ComputeProximity(srcBand, proxInBand, options)
proxIn = gdalnumeric.BandReadAsArray(proxInBand)
proxOut = gdalnumeric.BandReadAsArray(proxBand)
##distance tranform is the distance to zero pixel values minus distance to non-zero pixel values
proxTotal = proxIn.astype(float) - proxOut.astype(float)
proxTotal = proxTotal * metersIndex
if npDistFileName != '':
np.save(npDistFileName, proxTotal)
return proxTotal
def createDistanceTransform(rasterSrc, vectorSrc, npDistFileName='', units='pixels'):
## open source vector file that truth data
source_ds = ogr.Open(vectorSrc)
source_layer = source_ds.GetLayer()
## extract data from src Raster File to be emulated
## open raster file that is to be emulated
srcRas_ds = gdal.Open(rasterSrc)
cols = srcRas_ds.RasterXSize
rows = srcRas_ds.RasterYSize
noDataValue = 0
if units=='meters':
geoTrans, poly, ulX, ulY, lrX, lrY = gT.getRasterExtent(srcRas_ds)
transform_WGS84_To_UTM, transform_UTM_To_WGS84, utm_cs = gT.createUTMTransform(poly)
line = ogr.Geometry(ogr.wkbLineString)
line.AddPoint(geoTrans[0], geoTrans[3])
line.AddPoint(geoTrans[0]+geoTrans[1], geoTrans[3])
line.Transform(transform_WGS84_To_UTM)
metersIndex = line.Length()
else:
metersIndex = 1
## create First raster memory layer
memdrv = gdal.GetDriverByName('MEM')
dst_ds = memdrv.Create('', cols, rows, 1, gdal.GDT_Byte)
dst_ds.SetGeoTransform(srcRas_ds.GetGeoTransform())
dst_ds.SetProjection(srcRas_ds.GetProjection())
band = dst_ds.GetRasterBand(1)
band.SetNoDataValue(noDataValue)
gdal.RasterizeLayer(dst_ds, [1], source_layer, burn_values=[255])
srcBand = dst_ds.GetRasterBand(1)
memdrv2 = gdal.GetDriverByName('MEM')
prox_ds = memdrv2.Create('', cols, rows, 1, gdal.GDT_Int16)
prox_ds.SetGeoTransform(srcRas_ds.GetGeoTransform())
prox_ds.SetProjection(srcRas_ds.GetProjection())
proxBand = prox_ds.GetRasterBand(1)
proxBand.SetNoDataValue(noDataValue)
options = ['NODATA=0']
##compute distance to non-zero pixel values and scrBand and store in proxBand
gdal.ComputeProximity(srcBand, proxBand, options)
memdrv3 = gdal.GetDriverByName('MEM')
proxIn_ds = memdrv3.Create('', cols, rows, 1, gdal.GDT_Int16)
proxIn_ds.SetGeoTransform(srcRas_ds.GetGeoTransform())
proxIn_ds.SetProjection(srcRas_ds.GetProjection())
proxInBand = proxIn_ds.GetRasterBand(1)
proxInBand.SetNoDataValue(noDataValue)
options = ['NODATA=0', 'VALUES=0']
##compute distance to zero pixel values and scrBand and store in proxInBand
gdal.ComputeProximity(srcBand, proxInBand, options)
proxIn = gdalnumeric.BandReadAsArray(proxInBand)
proxOut = gdalnumeric.BandReadAsArray(proxBand)
##distance tranform is the distance to zero pixel values minus distance to non-zero pixel values
proxTotal = proxIn.astype(float) - proxOut.astype(float)
proxTotal = proxTotal*metersIndex
if npDistFileName != '':
np.save(npDistFileName, proxTotal)
return proxTotal