DAP Data Model Specification

Summary of the document: 

This document outlines the Data Model of the OPeNDAP (OPeNDAP) Data Access Protocol (DAP) Version 4.0, which serves as the framework for representing data sources, including various types of variables and constructor types. It details the structure of variables, attributes describing them, and how variables are sampled using constraint expressions. Additionally, it describes the interaction between clients and servers for data exchange and the persistent representation of data objects. The DAP specification is independent of underlying communication protocols, with HTTP being the most common implementation. The terminology clarifies that "client" and "server" refer to programs communicating via DAP, with flexibility in program implementation as long as they adhere to the specification. The document does not prescribe specific implementation details but rather outlines the dialog between clients and servers, allowing flexibility in data structure and transport methods.