Add information about dependencies on Linux to README.

Author: dtarb

GCC.sh

@@ -0,0 +1,25 @@
+# Install gcc-7 compiler from repository.  Has to be run sudo.
+# This was not run as a script, instead these were done by hand
+
+add-apt-repository -y ppa:ubuntu-toolchain-r/test
+apt update
+apt install -y gcc-7 g++-7
+
+# To set these as the default compilers (code from Tony https://github.com/Castronova/docker-image-build/blob/master/cuahsi/singleuser/install-taudem.sh) 
+sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-7 60 --slave /usr/bin/gcc-ar gcc-ar /usr/bin/gcc-ar-7 --slave /usr/bin/gcc-nm gcc-nm /usr/bin/gcc-nm-7 --slave /usr/bin/gcc-ranlib gcc-ranlib /usr/bin/gcc-ranlib-7
+sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-7 10
+
+# Instructions from Tony that could be used to revert or toggle between alternatives
+#sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-7 60 --slave /usr/bin/gcc-ar gcc-ar /usr/bin/gcc-ar-7 --slave /usr/bin/gcc-nm gcc-nm /usr/bin/gcc-nm-7 --slave /usr/bin/gcc-ranlib gcc-ranlib /usr/bin/gcc-ranlib-7
+#
+#sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-5 60 --slave /usr/bin/gcc-ar gcc-ar /usr/bin/gcc-ar-5 --slave /usr/bin/gcc-nm gcc-nm /usr/bin/gcc-nm-5 --slave /usr/bin/gcc-ranlib gcc-ranlib /usr/bin/gcc-ranlib-5
+#
+#sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-7 10
+#sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-5 10
+#
+#Now, gcc-7 is the default compiler. To change back to gcc-5, you need to run :
+#sudo update-alternatives --config gcc
+#Then select gcc-5.
+# e.g. 
+# echo 1 | update-alternatives --config gcc
+# echo 2 | update-alternatives --config gcc

GDAL.sh

@@ -0,0 +1,14 @@
+# Getting GDAL
+wget http://download.osgeo.org/gdal/2.3.0/gdal230.zip gdal230.zip 
+unzip gdal230.zip 
+cd gdal-2.3.0
+./configure --prefix=$HOME/TauDEMDependencies/gdal 
+make
+make install
+
+# The following 3 lines should also be appended to .bashrc
+export PATH=$HOME/TauDEMDependencies/gdal/bin:$PATH
+export LD_LIBRARY_PATH=$HOME/TauDEMDependencies/gdal/lib:$LD_LIBRARY_PATH
+export GDAL_DATA=$HOME/TauDEMDependencies/gdal/share/gdal
+# Test
+gdalinfo --version

MPICH2.sh

@@ -0,0 +1,13 @@
+# Script to setup MPICH
+wget http://www.mpich.org/static/downloads/3.2.1/mpich-3.2.1.tar.gz
+
+# Now following instructions in README
+tar xzf mpich-3.2.1.tar.gz
+mkdir mpich
+cd mpich-3.2.1
+./configure --prefix=$HOME/TauDEMDependencies/mpich/mpich-install 2>&1 | tee c.txt
+make 2>&1 | tee m.txt
+make install 2>&1 | tee mi.txt
+
+# Add the following to .bashrc
+PATH=$HOME/TauDEMDependencies/mpich/mpich-install/bin:$PATH ; export PATH

README.txt

@@ -18,3 +18,23 @@ cd src && mkdir build && cd build
 cmake ..
 make && make install
 The executables are written to /usr/local/taudem directory.  This can be changed at the second last line (following DESTINATION) if desired.
+
+Dependencies
+------------
+Dependencies include GDAL, MPI and C++ 2011.
+On Windows Dependencies are provided in the Windows Installer
+
+On Linux dependencies can be tricky.  I've added the following scripts to help, though you may need to adjust based on your system.  
+GDAL:  GDAL.sh installs from GDAL source. You could also try
+apt-get install gdal-bin libgdal-dev
+apt-get install gdal-bin=2.1.3+dfsg-1~xenial2
+
+C++: The script GCC.sh contains some commands I've used to get the required compiler.
+
+MPI: MPICH2.sh installs from mpich.org stable distribution source.
+sudo apt-get install openmpi-bin may also be an option, but I have not tried this.
+
+Testing
+-------
+See the repository https://github.com/dtarb/TauDEM-Test-Data for test data and scripts that exercise every function.  These can also serve as examples for using some of the functions.
+