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The topics covered on this page include information regarding the creation and management of ECHO submitted through ECHO. It is the responsiblity of the Client Partner to accurately represent the ordering capabilities which ECHO and the Data Partners provide.
The information provided is broken up into the following topic areas:
- Order Workflow - An overview of how ECHO processes metadata queries.
- Order Options - The mechanism by which a specific information is requested from a user at the time of ordering.
- Forms Specification - The specific syntax and features utilized by ECHO Client Partners when displaying an order option definition.
- Special Considerations - Highlighted topics regarding metadata discovery of which Client Providers should be aware.
Within ECHO, there are two types of 'orders' which are used to track the request for data from a Data Partner:
- ECHO Order - A list of metadata items which will be, or has been, requested from one or more ECHO Data Partner. The order also includes necessary information regarding the user and any data-specific order options.
- Provider Order - A list of metadata items requested from a single ECHO Data Partner, associated with a submitted ECHO order.
The ECHO API facilitates asynchronous creation, updating, and submission of ECHO Orders. An order created in ECHO will persist indefinetely, unless removed explicity by a user. Once an order is created, metadata items may be added, updated, or removed through the API. Some providers support the quoting activity, which allows a user to submit their order to a provider to view the final cost prior to submission. As a part of quoting and submission, an ECHO order will be validated.
Once an valid order is submitted, the appropriate ECHO Data Partners will be contacted, and the order will be fulfilled via the provider's order delivery mechanisms. As an order is processed, the Data Partners will update the order's status. An ECHO Client may choose to allow registered users to view the status of a submitted order.
ECHO Order Options
The term "order option" refers to the mechanism by which a Data Partner can request specific information from a user at the time of ordering. For example, an order option may require that users provide ftp-push information, or specific subsetting information. The ECHO Forms Specification defines the structure and content of the XML documents which are used in ECHO to specify the order options assigned to a collection within the ECHO data catalog. The term "ECHO Form" is used to refer to the XML document created using the standards in the ECHO Forms Specification.
It is the responsibility of the ECHO Data Partners to design, upload, and assign order options to their catalog items using the ECHO Forms Specification. If a provider's collection does not allow ordering, then an order option may not be assigned. It is also the responsibility of the Data Partner to verify that their order options correctly define the information needed to complete the order process.
It is the responsibility of an ECHO Client Partner which is offering the service of ordering ECHO data to implement functionality that will display the ECHO Form. It is strongly encouraged that a Client Partner implementing the ordering functionality ensure that the entire ECHO Forms Specification can be represented. ECHO Data Partners may choose to utilize any and all parts of the specification. If ordering is not a feature which is included in the scope of a Client Partner's work, then they need not implement the ECHO Forms Specification.
Provider vs System Level Forms
The ECHO Forms that are created and uploaded by Data Partner are referred to as "provider level forms." This designates the fact that they are visible only to the Data Partner who uploaded the form. There are also ECHO Forms that are created and uploaded by the ECHO Team, and they are referred to as "system level forms." These forms are visible to all providers. The purpose of system level forms is to centralize common option definition elements which can be shared by all providers in order to reduce duplication of form components.
ECHO Forms Specifcation
The ECHO Forms Specification, found below, outlines the complete set of syntax and features utilized by ECHO Data Partners when creating ECHO Forms. The specification also describes the workflow and user interface elements which are used as form controls. Also found below are links to the XML Schemas defining the ECHO Form's XML structure.
- ECHO Forms Specification - (PDF)
- Autopopulate XML Schema - (XSD)
- ECHO Forms XML Schema - (XSD)
In order to facilitate ECHO Forms development, some sample provider forms and the current ECHO system form are provided below. Also included is the ECHO Forms Sandbox webpage which may be used to display realtime forms processing.
- Basic FTPPush/Pull & SCP Provider Level Form - (XML) (JPG) - This form which utilizes a very simple structure where the user has three distribution methods. Only the FTPPush option is shown in the image.
- Basic Media & Relevancy Provider Level Form - (XML) (JPG) - This form which contains options for FTP Push, Pull, CD-ROM, DLT, or DVD media distributions. The provided image shows each media option resulting in different information prompted from the user. This form takes advantage of the 'relevancy' functionality of the forms to determine when or when not to display certain items.
- Advanced FTPPush/Pull Provider Level Form - (XML) (JPG) - This form is similar to the xmlFTP_Media example, however it allows a user to enter subsetting information based upon spatial or parameter subsetting. This form takes advantage of an xpath constraint to enforce that the user choose a subsetting parameter scheme. Finally, you will see that this form uses the autopopulate capabilities of the ECHO forms specification to populate the size of the granule into the subsetting options.
- Advanced FTPPush/Pull Provider Level Form - (XML) (JPG) - This form provides another example using relevancy, subsetting options, and the autopopulate capabilities.
- System Level Order Option - (XML) - The current system level form provided by ECHO.
- ECHO Forms Sandbox - (ZIP)
The following items outline some common areas which Client Partners should be aware of while fulfilling orders in ECHO..
ISO-3166 Country Names
The ECHO system allows user to enter a freeform string to define their contact, shipping, or billing address. In cooperation with the EOSDIS User Services Working Group, ECHO has created a list of approved country names that complies with the ISO 3166 standard. This list of names will appear in the ECHO supported PUMP and WIST tools for for user registration and order creation in WIST. ECHO will support all countries on this list and additional user-entered countries. ECHO Client Partners are encouraged to use this list in their applications to provide a consistent list of countries to all ECHO users. The full list can be downloaded below.