add details about SNAP software to doco [ci skip]

Author: Matt Garthwaite

README.rst

@@ -14,6 +14,7 @@ Python tool for InSAR Rate and Time-series Estimation
    :target: https://pypi.org/project/Py-Rate/ 
 
 PyRate is a Python tool for estimating the average displacement rate (velocity) and cumulative displacement time-series of surface movements for every pixel in a stack of geocoded unwrapped interferograms generated by Interferometric Synthetic Aperture Radar (InSAR) processing. PyRate uses a "Small Baseline Subset" (SBAS) processing strategy and currently supports input data in the GAMMA or ROI_PAC software formats.
+Additionally, the European Space Agency `SNAP software <https://step.esa.int/main/download/snap-download/>`_ version 8 has a "PyRate export" capability that prepares SNAP output data in the GAMMA format for use with PyRate.
 
 The PyRate project started in 2012 as a partial Python translation of "Pirate", a Matlab tool developed by the University of Leeds and the Guangdong University of Technology.
 

docs/index.rst

@@ -9,6 +9,11 @@ geocoded unwrapped interferograms generated by Interferometric Synthetic
 Aperture Radar (InSAR) processing. `PyRate` exploits distributed scatterers
 using a "Small Baseline Subset" (SBAS) processing strategy and currently
 supports input data in the `GAMMA` or `ROI\_PAC` software formats.
+Additionally, the European Space Agency SNAP_ software version 8 has a
+"PyRate export" capability that prepares `SNAP` output data in the `GAMMA`
+format for use with `PyRate`.
+
+.. _`SNAP`: https://step.esa.int/main/download/snap-download/
 
 .. note::
 

docs/usage.rst

@@ -407,15 +407,10 @@ in order as a single job. This could be useful for batch processing runs.
 Input Files
 -----------
 
-`PyRate` currently supports input files generated by the `GAMMA` and `ROI\_PAC`
-interferometry softwares. `PyRate` will determine the input format from the 
-``processor:`` parameter in the configuration file (``0``: `ROI\_PAC`;
-``1``: `GAMMA`).
-
-.. note::
-
-    - Support and development of `ROI\_PAC` has been discontinued.
-    - `ROI\_PAC` support in `PyRate` will be deprecated in a future release.
+`PyRate` currently supports input files generated by the `GAMMA`, `ROI\_PAC`
+and `SNAP` interferometry softwares. `PyRate` will determine the input
+format from the ``processor:`` parameter in the configuration file
+(``0``: `ROI\_PAC`; ``1``: `GAMMA` (and `SNAP`)).
 
 `GAMMA`
 ^^^^^^^
@@ -430,6 +425,23 @@ matching based on date epochs given in the filenames.
 A DEM with matching size and geometry to the interferograms can also be processed.
 The DEM absolute path and filename are set with the ``demfile`` parameter.
 
+`SNAP`
+^^^^^^
+
+The European Space Agency SNAP_ software has supported PyRate since version
+8.0.0. Users can convert their output data in to `GAMMA` format by
+using the "PyRate export" function in `SNAP`. Then users should follow the
+`PyRate` instructions for `GAMMA`-formatted data.
+
+.. note::
+
+    - The capability to generate SBAS interferogram networks that are needed
+      for time series analysis of large InSAR stacks in `PyRate` is planned
+      for a future version of `SNAP`.
+
+.. _SNAP: https://step.esa.int/main/download/snap-download/
+
+
 `ROI\_PAC`
 ^^^^^^^^^^
 
@@ -442,6 +454,11 @@ from the DEM header file.
 A DEM with matching size and geometry to the interferograms can also be processed.
 The DEM absolute path and filename are set with the ``demfile`` parameter.
 
+.. note::
+
+    - Support and development of `ROI\_PAC` has been discontinued.
+    - `ROI\_PAC` support in `PyRate` will be deprecated in a future release.
+
 .. _parallel_label:
 
 Parallel Processing