A user uses OPeNDAP with an OPeNDAP client program. This client program may have been acquired by the user (for example, the OPeNDAP Matlab and IDL graphic user interfaces, or Ferret, a freeware data analysis package each use OPeNDAP for data access), or may be a program converted to use the OPeNDAP library for data access (see Chapter 3.
In either case, there are a set of issues that must be addressed in order to use a program to access data through OPeNDAP. The issues can be classed into two groups. One set of issues involves configuring the system to provide OPeNDAP with the helper applications and environment variables it requires. The other set concerns the manner in which a user communicates with an OPeNDAP server. We cover this first.