Merge de0c783 into 5d8ef80

README.md

@@ -2,7 +2,25 @@
 [![Coverage Status](https://coveralls.io/repos/github/LSSTDESC/imSim/badge.svg?branch=master)](https://coveralls.io/github/LSSTDESC/imSim?branch=master)
 
 # imSim
-GalSim based LSST simulation package
+imSim is a software package that simulates the LSST telescope and survey.
+It produces simulated images from the 3.25 Gigapixel camera which are suitable
+to be processed through the LSST Data Management pipeline. imSim takes as an
+input a catalog of astronomical sources along with information about how the light
+is distorted on the way to Earth including lensing and extinction information.  The
+images which are produced include the the systematic effects of the atmosphere,
+optics and sensors on the observed PSF.
+
+imSim calls the [GalSim](https://github.com/GalSim-developers/GalSim "GalSim GitHub Page") library for astronomical object rendering and is designed to be used inside of the
+LSST and LSST Simulation Group software environment.  It is not a stand alone
+program.  It requires a working LSST software stack to build and run.
+
+Communication with the imSim development team should take place through the
+[imSim GitHub repository](https://github.com/LSSTDESC/imSim) which is part of the
+DESC GitHub organization.  Other question can be directed to Chris Walter at Duke University.
+
+## imSim models
+
+Details on the models implemented by imSim including their validations can be found in the [imSim Feature Matrix](https://github.com/LSSTDESC/imSim/wiki/Feature-Matrix).
 
 ## Set up
 Set up the `lsst_sims` distribution, then enter the following from
@@ -74,6 +92,16 @@ optional arguments:
                         created and saved to that filename.
   --image_path IMAGE_PATH
                         search path for FITS postage stamp images.This will be
-                        prepended to any existing IMSIM_IMAGE_PATHenvironment
-                        variable, for which $CWD is included bydefault.
+                        prepended to any existing IMSIM_IMAGE_PATH environment
+                        variable, for which $CWD is included by default.
 ```
+
+## Release Status
+The list of released versions of this package can be found [here](https://github.com/LSSTDESC/imSim/releases), with the master branch
+including the most recent (non-released) development.  imSim is currently
+still considered beta code.
+
+## Licensing and ownership
+This software was developed within the LSST DESC using LSST DESC resources, and
+so meets the criteria given in, and is bound by, the LSST DESC Publication Policy
+for being a “DESC product”.  imSim is licensed with a BSD 3-Clause "New" or "Revised" License as detailed in the included LICENSE file.