Update README.md

README.md

@@ -35,13 +35,10 @@ Support Data (ISD)* file.
 
 Under the CSM standard, each plugin library can define its own ISD
 camera model format. This library uses an auxiliary JSON formatted file that must
-be next to the image file passed to the CSM::ISD class. We provide an
-OpenAPI server for generating these,
-[pfeffernusse](https://github.com/USGS-Astrogeology/pfeffernusse). The
-swagger specification is located on
-[swaggerhub](https://app.swaggerhub.com/apis/USGS-Astro/pfeffernusse2/0.1.4-oas3).
-You can also use [ALE](https://github.com/USGS-Astrogeology/ale)
-directly with metakernels to generate the auxiliary JSON file.
+be next to the image file passed to the CSM::ISD class.
+ISD files and strings can be generated by using [ALE](https://github.com/USGS-Astrogeology/ale)
+with metakernels and accompanying SPICE kernels, or from ISIS cubes that have attached
+SPICE data.
 
 The camera model read from an ISD file is converted at load time to an
 internal representation which makes camera operations more