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...ll contains Grid variables with latitude and longitude maps. For DAP4, the responses will be coverages with latitude and longitude domain variables.

...(DAP). The current version of the DAP is version 2, usually referred to as DAP2. In addition to DAP2 responses, most OPeNDAP servers provide a number of additional services such as:

...required by the DAP must be present in the content of the DAP requests and responses. The DAP won't uniquely embed information required by the DAP into HTTP He ...ossible for that data set, including URLs that can be used to access those responses.

* DAP2 JSON <-> DAP2 ** Have OLFS ask BES what responses are supported for a particular dataset: For example, the covjson handler in

...sponses for these commands. The format for each of these commands is <code>dap2</code>.

...in kind. Some requests specifically indicate a non XML response (such as a DAP2 binary response) in which case the response will be as requested. === Responses ===

...he basic BES command (e.g., ''show version''), the DAP commands and return responses using HTTP, does not need to specialize the command set, the response types :These holds specific types of responses for the DAP

If you are serving up OPeNDAP data responses (DAS, DDS, DataDDS) then you will have loaded the dap commands in your conf ...''ddx'' is the DAP4 counterpart to the ''das'' and ''dds'' responses from DAP2. The dataddx response is a true multipart MIME document with the first part

...sponses for these commands. The format for each of these commands is <code>dap2</code>. ...ill in a particular response, such as DAS, DDS, DataDDS, help, and version responses, for example.

...L module provides the ability to return various kinds of GIS data files as responses from Hyrax. The handler currently supports returning GeoTIFF and JPEG2000 f ...an use this module to transform your data. You can get GeoTIFF or JPEG2000 responses for applicable datasets by appending the extensions ''.tiff'' or ''.jp2'' t

...ed to specify a "returnAs" format. Typically you will see responses of the dap2 format. This module provides the additional format of returning the OPenDAP <setContext name="dap_format">dap2</setContext>

* Level three data will be DAP2 Grids or DAP4 Coverages and look like they can easily be aggregated using N ...se. However, the same sequence diagram applies to the netCDF3/4 and 'file' responses.''</font>

== Supporting both DAP2 and DAP4 == ...provides a way for simple web browsers to display links to these different responses, all in a way that's transparent to the browser, something that the 'versio

...) to provide data and catalog services to clients. The OLFS implements the DAP2 protocol and supports some of the new DAP4 features. :Anything that can be referenced by a DAP URL and that will return the DAP responses when requested.

...are some new data model components in netCDF that are hard to represent in DAP2 (hence the 'almost' in the preceding paragraph). If the handler, as of vers === Mappings between NetCDF version 4 data model and DAP2 data types ===

= Responses = DAP4 defines two core responses that represent all of the information in a dataset:

...apabilities document with links to both DAP2 and DAP4 resources allows for DAP2 backward compatibility and will support protocol extensibility and future e === DAP2 DAS ===

...containing the appropriate DAP4 response. This document describes the DAP4 responses, the manner in which they are bundled into MIME-Documents, and the chunked All DAP4 responses from a DAP4 server will be chunked, independently of any chunking utilized

== DAP2 and DAP4 Specification efforts == The original (2004) DAP4 specification work morphed into separate DAP2 and DAP4 specification efforts. The [http://www.opendap.org/pdf/ESE-RFC-004

<setContext name="dap_format">dap2</setContext> One thing that's nice about DAP is that so many of the responses are ASCII or XML. That makes them easy (relatively) to debug when compared

...he details of the various service URLs. A THREDDS catalog might identify a DAP2 service, but the URL that can be assembled from the THREDDS catalog for tha This URL points to a dataset on a DAP2 server:

<blockquote>In DAP2, the DDS is used as a descriptive header for data. For gridded data that wo ...another part, so that other protocols (e.g., DAP-SOAP) can package several responses in one document easily. That is, while this design does not provide for tha

...AP is pleased to announce the release of Hyrax 1.16.8. This version of the DAP2 and DAP4 data server is available as RedHat 8 and CentOS 7 RPM packages, Do • Modified fileout_netcdf handler to allow netcdf-3 responses to be up to 4GB in size.

== WCS data access via DAP2 requests == Responses are generated by either returning the THREDDS catalog as the source XML, or

...ed DAP-compatible clients and servers) it highlights how DAP4 differs from DAP2. ...ast sentence is rendered unnecessary and wrong by the first sentence where DAP2, DAP4, and DAP are define (somewhat implicitly). - Ethan

...UST support when utilizing the HTTP protocol to transmit DAP4 requests and responses, along with additional optional services that DAP4-compliant software SHOUL The DAP4 protocol uses three basic responses to represent a data resource. One response, the Dataset Metadata Response

As part of the DAP2 --> DAP4 transition process, we are soliciting ''use cases regarding DAP cl # <del> [[DAP4: Responses | Responses]]</del>

...segment. This provides an easy way for the OLFS to combine several DataDDX responses in a single MP MIME document (easy in the sense that the OLFS does not have ...be good from the standpoint of support for protocols that don't want data responses in multipart MIME documents, but it's far from optimal since the DDS has to

established in the DAP2 protocol a grid. This has been an ongoing source of problems in DAP2

...AP Data Server, Hyrax, is a data server developed by OPeNDAP that supports DAP2, DAP4 and other Web APIs for data access. These pages contain documentation ...ications for modules that read data as well as ones that transform the DAP responses into other things, such as taking a binary data object and transforming it

...or this interface to Hyrax's aggregation software, we provide two kinds of responses: Data in multiple files that are bundled together using an zip archive and ;operation: Use ''operation'' to select from various kinds of responses. The form of the response also determines how the aggregation is built. The

...th five existing handlers that read data and return DAP2 metadata and data responses. The libdap and bes software have been modified to provide support for all ...to modify a module so that it will support DAP4, in addition to supporting DAP2. The basic steps are pretty simple:

...for now, that the DAP4 constraint language will be closely related to the DAP2 constraint language. We will start with projections and address the issue o As with DAP2, it can be assumed that a projection walks a path from the root dataset to

...UST support when utilizing the HTTP protocol to transmit DAP4 requests and responses, along with additional optional services that DAP4-compliant software SHOUL The DAP4 protocol uses three basic responses to represent a data resource. One response, the Dataset Metadata Response

...plus other services that have been added over time such as the RDF and ISO responses. There is currently no way for a user (or software agent) to discover which ...latter could be quite complicated. The alternative is to have all possible responses described in the services description with the understanding that they migh

...pendap.org/index.php/DAP4:_Responses#Dataset_Response please see the DAP4: Responses page.] ...too large for that type. This is true because DAP4 will use XDR to encode responses and thus Arrays of Enumerations will encode directly to single byes. If we

...Bureau of Meteorology we have developed prototype JSON data and metadata responses for Hyrax. After reviewing some the existing JSON encodings for DAP conten ...made of a controlled vocabulary. This means that clients utilizing these responses can always "know" what to look for in each returned object. No matter what

...Some transforms operate on source XML from internal documents such as BES responses. Other transforms change things like THREDDS catalogs into HTML for browser ...contains the XSLT transformation that is used to transform BES showCatalog responses into THREDDS catalogs.

: Run ALL hyrax tests on the resulting dmr++ file and compare the responses the ones generated by the source hdf5 file. : Run hyrax inventory tests on the resulting dmr++ file and compare the responses the ones generated by the source hdf5 file.

##The type must be the name of a value DAP2 simple type (Byte, ..., Float64). #make_array will build a DAP2 Array with the values and return a BaseType* to that array

...y are not the only way that information can be accessed. For example, DAP4 responses return version information and it makes sense to incude that in the HTTP re ...re N-dimensional arrays of values bound to 1 to N coordinate variables. In DAP2 the Grid type was limited to one-dimensional coordinate variables; in DAP4

...nt I'm not going to look at the latter case because experience so far with DAP2 has not provided any indication that would present any performance benefits ...roposal covers only the DAP4 data response; it does not apply to the other responses including, e.g., an ASCII data response.

=== Mappings between the HDF4 data model and DAP2 data types === ;SDS :This is mapped to a DAP2 Grid (if it has a dimension scale) or Array (if it lacks a dim scale).

;Asynchronous responses: Asynchronous responses are needed for an awful lot of things. Mostly, we need this in the protocol ...red to a specific client or type of client. Other things like asynchronous responses will break clients that have been 'living off' the current behavior that ea

: Responds to requests for DAP responses ...equests, including some, like the ASCII response that are not strictly DAP responses, are handled.

...e native API for the type. Since older clients wouldn't be asking for DAP4 responses, I imagine the location information would get pushed in to the Attribute sp ...a DAP4 Grid with some additional attributes. It probably cannot decay to a DAP2 Grid in the general case, although in common special cases it can (because

...a CSV table, encoded using ASCII characters. Excel can read these kinds of responses, e.g., but it's kind of an unusual way to package satellite data. ...they held - same names and types. I determined this by looking at the DDS responses for the variables.

established in the DAP2 protocol a grid. This has been an ongoing source of problems in DAP2

...pe, this may be fairly easy. It appears likely that RDF can be embedded in DAP2 and that changes can be made to DAP4's DDX object to make that even easier. # Asynchronous responses.

...that users that are not authenticated will only be allowed to receive data responses that are smaller than an adjustable threshold size. # Support for the new API features that are compatible with DAP2 - Implementation

** Attributes can be DAP2 types as well as the NcML types ...a global attribute. However, to support older clients that only understand DAP2, the handler will bundle top-level non-container attributes into a containe

The catalog cache element configures the OLFS memory cache of BES catalog responses. This cache can greatly increase server performance for small requests. It * The value of <tt>maxEntries</tt> determines the total number of catalog responses to hold in memory. The default value for <tt>maxEntries</tt> is 10000.

<setContext name="dap_format">dap2</setContext> ...scmd'' and modify it as your debug needs change, such as to test different responses.

This document takes material from the DAP2 specification and <td>Added sections for DSR, Async, and Error responses and their schemas</td>

...suppress the serialization of their parent sequence (as was the case with DAP2) the code to handle the sequence serialization becomes very complex. We mad I'm tweaking my code to process the chunked responses and thinking about what the end chunk means. Does the end chunk mean that o