给定一个国家的地形GIS栅格crop.tif
:
# download:
curl -o ETOPO1.zip 'http://www.ngdc.noaa.gov/mgg/global/relief/ETOPO1/data/ice_surface/grid_registered/georeferenced_tiff/ETOPO1_Ice_g_geotiff.zip'
# unzip:
unzip ETOPO1.zip
# crop:
gdal_translate -projwin -005.50 051.30 10.00 041.00 ETOPO1_Ice_g_geotiff.tif crop.tif
给定高程阈值 n = 50(米)
如何将所有 z >= n 的像素值设置为 50?
相关问题:https://stackoverflow.com/questions/18300210/,Gdal: How to get a pixel's value from raster image?
帮助:gdallocationinfo 可以获取一个点的值(无需迭代整个图像):
$ gdallocationinfo crop.tif 1 1 -valonly
> 73