Install error on Windows machine for rasterio

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Hello,
I am attempting to install and running into the error below. python version 3.7.3

ERROR: Complete output from command 'C:\Users\xx\AppData\Local\Continuum\anaconda3\python.exe' 'C:\Users\xx\AppData\Local\Continuum\anaconda3\lib\site-packages\pip\_vendor\pep517\_in_process.py' get_requires_for_build_wheel 'C:\Users\xx\AppData\Local\Temp\tmp9hjbg_ow':
ERROR: INFO:root:Building on Windows requires extra options to setup.py to locate needed GDAL files. More information is available in the README.
ERROR: A GDAL API version must be specified. Provide a path to gdal-config using a GDAL_CONFIG environment variable or use a GDAL_VERSION environment variable.
----------------------------------------
ERROR: Command "'C:\Users\xx\AppData\Local\Continuum\anaconda3\python.exe' 'C:\Users\xx\AppData\Local\Continuum\anaconda3\lib\site-packages\pip\_vendor\pep517\_in_process.py' get_requires_for_build_wheel 'C:\Users\xx\AppData\Local\Temp\tmp9hjbg_ow'" failed with error code 1 in C:\Users\xx\AppData\Local\Temp\pip-install-hcrhz_xh\rasterio

Start with the README's Windows installation guidance and setup.py, then reproduce the Python 3.7.3 installation failure using the reported pip output. Check how GDAL_CONFIG and GDAL_VERSION are handled; done means the documented Windows installation completes without the missing GDAL API error.

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