docs: standardize requirement files

+ rename the following files:
   - readthedocs.yml -> .readthedocs.yaml
   - docs/requirements.txt -> docs/requirements4rtd.txt
   - docs/conda.txt -> docs/requirements.txt
   - docs/conda_env.yml -> docs/environment.yml

+ update installation notes in mintpy installation page, circle CI and docker file.

.circleci/config.yml

@@ -39,7 +39,7 @@ jobs:
             git clone https://github.com/insarlab/PySolid.git ${HOME}/tools/PySolid
             # install dependencies
             source activate root
-            mamba install --verbose --yes --file ${MINTPY_HOME}/docs/conda.txt gdal>=3 fortran-compiler
+            mamba install --verbose --yes --file ${MINTPY_HOME}/docs/requirements.txt gdal>=3 fortran-compiler
             pip install git+https://github.com/tylere/pykml.git
             # compile pysolid Fortran code
             cd ${HOME}/tools/PySolid/pysolid

readthedocs.yml → .readthedocs.yaml

@@ -17,9 +17,9 @@ mkdocs:
 formats: all
 
 # Optionally set the version of Python and requirements required to build your docs
+# conda method does not work because of the "command killed due to excessive memory consumption" error
 python:
-  version: 3.6
+  version: 3.7
   install:
-    - requirements: docs/requirements.txt
+    - requirements: docs/requirements4rtd.txt
 
-formats: []

docker/Dockerfile

@@ -55,7 +55,7 @@ RUN wget https://repo.continuum.io/miniconda/Miniconda3-4.5.4-Linux-x86_64.sh &&
 
 # Install dependencies
 RUN ${PYTHON3DIR}/bin/conda config --add channels conda-forge && \
-    ${PYTHON3DIR}/bin/conda install --yes --file ${MINTPY_HOME}/docs/conda.txt
+    ${PYTHON3DIR}/bin/conda install --yes --file ${MINTPY_HOME}/docs/requirements.txt
 
 # Install pykml
 RUN ${PYTHON3DIR}/bin/pip install git+https://github.com/yunjunz/pykml.git

docs/conda_env.yml → docs/environment.yml

@@ -1,5 +1,5 @@
-# create environment : conda env create -f conda_env.yml
-# update dependencies: conda env update -f conda_env.yml
+# create environment : conda env create -f environment.yml
+# update dependencies: conda env update -f environment.yml
 # remove environment : conda env remove -n mintpy
 # enter  environment : conda activate mintpy
 # exit   environment : conda deactivate
@@ -32,7 +32,7 @@ dependencies:
   - ecCodes
   - netcdf4
   - pygrib
-  - pyhdf
+  # - pyhdf   # required by MERRA, which is currently not supported in pyaps3
   # for pyresample
   - pyresample
   - openmp

docs/installation.md

@@ -71,7 +71,7 @@ Run the following in your terminal to install the dependencies to your conda env
 
 # Add "gdal>=3" below to install extra dependencies if you use ARIA, FRInGE, HyP3 or GMTSAR
 # Add "isce2"   below to install extra dependencies if you use ISCE-2
-conda install --yes -c conda-forge --file ~/tools/MintPy/docs/conda.txt
+conda install --yes -c conda-forge --file ~/tools/MintPy/docs/requirements.txt
 
 $CONDA_PREFIX/bin/pip install git+https://github.com/insarlab/PySolid.git
 $CONDA_PREFIX/bin/pip install git+https://github.com/tylere/pykml.git
@@ -80,7 +80,7 @@ $CONDA_PREFIX/bin/pip install git+https://github.com/tylere/pykml.git
 Or run the following in your terminal to install the dependencies to a new environment _**mintpy**_:
 
 ```
-conda env create -f $MINTPY_HOME/docs/conda_env.yml
+conda env create -f $MINTPY_HOME/docs/environment.yml
 conda activate mintpy
 ```
 

docs/requirements.txt

@@ -1,17 +1,32 @@
-# requirements.txt for readthedocs, which uses pip and could not handle python>=3.6
-# conda.txt        for actual installation via conda
-# conda_env.yml    for actual installation via conda create environment
-# ports.txt        for actual installation via mac-ports
-# setup.py         for actual installation via pip [not finished yet]
+# requirements4rtd.txt for readthedocs, which uses pip with limited memory usage
+# requirements.txt     for actual installation via conda
+# environment.yml      for actual installation via conda create environment
+# ports.txt            for actual installation via mac-ports
+# setup.py             for actual installation via pip [not finished yet]
+python>=3.6,<3.9
+cartopy
 cvxopt
 dask>=1.0
 dask-jobqueue>=0.3
 defusedxml
-h5py
+h5py<3
 lxml
 matplotlib
 numpy
+pip
 pyproj
-pyresample
 scikit-image
 scipy
+# pyaps dependencies
+cdsapi
+ecCodes
+netcdf4
+pygrib
+# pyhdf  # required by MERRA, which is currently not supported in pyaps3
+# pyresample dependencies
+pyresample
+openmp
+pykdtree
+xarray
+zarr
+

docs/requirements4rtd.txt

@@ -0,0 +1,8 @@
+# requirements file to build Read the Docs ONLY
+defusedxml
+h5py
+lxml
+matplotlib
+numpy
+pyproj
+scipy