Created
March 20, 2013 01:45
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read pixel value from GeoTiff raster file by lat lon
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#!/usr/bin/env python | |
#http://geoinformaticstutorial.blogspot.it/2012/09/reading-raster-data-with-python-and-gdal.html | |
#http://www.gis.usu.edu/~chrisg/python/2009/lectures/ospy_slides4.pdf | |
from osgeo import gdal,ogr | |
from osgeo.gdalconst import * | |
import struct | |
import sys | |
lon = 12.502742 | |
lat = 42.243713 | |
lat = float(sys.argv[2]) | |
lon = float(sys.argv[3]) | |
def pt2fmt(pt): | |
fmttypes = { | |
GDT_Byte: 'B', | |
GDT_Int16: 'h', | |
GDT_UInt16: 'H', | |
GDT_Int32: 'i', | |
GDT_UInt32: 'I', | |
GDT_Float32: 'f', | |
GDT_Float64: 'f' | |
} | |
return fmttypes.get(pt, 'x') | |
ds = gdal.Open(sys.argv[1], GA_ReadOnly) | |
if ds is None: | |
print 'Failed open file' | |
sys.exit(1) | |
transf = ds.GetGeoTransform() | |
cols = ds.RasterXSize | |
rows = ds.RasterYSize | |
bands = ds.RasterCount #1 | |
band = ds.GetRasterBand(1) | |
bandtype = gdal.GetDataTypeName(band.DataType) #Int16 | |
driver = ds.GetDriver().LongName #'GeoTIFF' | |
success, transfInv = gdal.InvGeoTransform(transf) | |
if not success: | |
print "Failed InvGeoTransform()" | |
sys.exit(1) | |
px, py = gdal.ApplyGeoTransform(transfInv, lon, lat) | |
structval = band.ReadRaster(int(px), int(py), 1,1, buf_type = band.DataType ) | |
fmt = pt2fmt(band.DataType) | |
intval = struct.unpack(fmt , structval) | |
print round(intval[0],2) #intval is a tuple, length=1 as we only asked for 1 pixel value | |
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needed this in nodejs, and this solution got me there. thanks!