DAP4 Extension: CSV Data Encoding and Response

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This document specifies the DAP4 CSV data encoding and its use with the DAP4 protocol.

The DAP4 CSV data encoding represents DAP4 data

requests can constrain the data to be returned using a standard DAP4 Constraint Expression [DAP4 CE]

This DAP4 Extension describes the DAP4 CSV data encoding, the details needed so that a DAP4 server can advertise their support for the DAP4 CSV encoding, and how DAP4 clients can request DAP4 CSV encoded data responses. Though based on the text/csv media type described in RFC 4180^{[RFC 4180]}, the DAP4 CSV is more complex so that it can represent the more complex data structures of the DAP4 data model.

DAP4 Extension Details

Servers list supported DAP4 extensions in Dataset Service Response [DSR] extension elements. An extension element contains a name, role URI, and description.

The Role URI for the DAP4 CSV Data Encoding is

http://services.opendap.org/dap4/extension/text-csv-data

To advertise that a particular dataset supports the DAP4 CSV Data Encoding and Response encoding (i.e., data can be requested for that subset in the DAP4 CSV data encoding) support for the DAP4 CSV Data Encoding extension , a DAP4 server MUST include an extension element in a DSR

A DAP4 server wishing to advertise support for the DAP4 CSV Data Encoding MUST list the following Role URI

Name: DAP4 CSV Data Encoding

Role URI:

Description:

Requesting DAP4 CSV Encoded Data Response

URL Suffix	Media Type	URL Example
".dap" or ".dap.csv"	application/vnd.opendap.dap4.data+csv DAP4 CSV encoding	http://server/path/dataset.nc.dap http://server/path/dataset.nc.dap.csv
".dap.csv"	text/csv DAP4 CSV (UTF-8) Data encoding with generic media type	http://server/path/dataset.nc.dap.csv

Normative References

[RFC 4180] Common Format and MIME Type for Comma-Separated Values (CSV) Files

[DAP4 Vol1] DAP4 Volume 1: Data Model, Persistent Representations, and Constraints.

[DAP4 Extensions] [DAP4:_Specification_Volume_1#Extensions|DAP4 Volume 1, Section 9.3 Extensions]