Documenting Browse Graphics

Browse graphics and other multimedia samples are important aids to data discovery and assessment and can also be used to create image links to resources. The common dialects treat browse graphics in similar ways with names, URLs, file types and descriptions.

NASA GCMD Directory Interchange Format

Browse Graphics are described in DIF using the Multimedia_Sample field. They have the following properties:

<dif:Multimedia_Sample>
   <dif:File>dataSets_img.jpg </dif:File>
   <dif:URL>http://gcmd.nasa.gov/images/gui/dataSets_img.jpg</dif:URL>
   <dif:Format>jpg</dif:Format>
   <dif:Caption>discover and access data descriptions, relevant to global change and Earth science research.</dif:Caption>
   <dif:Description>The dataset image from the GCMD homepage </dif:Description>
</dif:Multimedia_Sample>
 

ECHO

The ECHO model includes browse images that are hosted by the data provider or by ECHO (User's Guide).

If the data provider is hosting the browse image, then the metadata contains an externally accessible URL (echo:ProviderBrowseURL) and other information abut the browse file.

  <echo:AssociatedBrowseImageUrls>
    <echo:ProviderBrowseUrl>
      <echo:URL>http://daac.nasa.gov/MODIS/2009/03/02/BR:036015124.jpg</echo:URL>
      <echo:FileSize>558403<</echo:FileSize>
      <echo:Description>MODIS Browse Image</echo:Description>
      <echo:MimeType>/*/AssociatedBrowseImageUrls/ProviderBrowseUrl/MimeType</echo:MimeType>
    </echo:ProviderBrowseUrl>
   </echo:AssociatedBrowseImageUrls>

If ECHO is hosting the browse image, the metadata includes the ECHO ID for the browse image.

   <echo:AssociatedBrowseImages>
    <echo:ProviderBrowseId>BR:036015124</echo:ProviderBrowseId>
  </echo:AssociatedBrowseImages>

ISO

ISO 19115-1 uses the mcc:MD_BrowseGraphic object to describe browse graphics. They include the following properties:

<mri:graphicOverview>
    <mcc:MD_BrowseGraphic>
        <mcc:fileName>
            <gco:CharacterString>Name of the file</gco:CharacterString>
        </mcc:fileName>
        <mcc:fileDescription>
            <gco:CharacterString>File Description</gco:CharacterString>
        </mcc:fileDescription>
        <mcc:fileType>
            <gco:CharacterString>This should be a mimeType</gco:CharacterString>
        </mcc:fileType>
        <mcc:imageConstraints>
            <mco:MD_Constraints/>
        </mcc:imageConstraints>
        <mcc:linkage>
            <cit:CI_OnlineResource>
              <cit:linkage>
                 <gco:CharacterString>The URL for the browse graphic</gco:CharacterString>
              </cit:linkage>
            </cit:CI_OnlineResource>
        </mcc:linkage>
    </mcc:MD_BrowseGraphic>
</mri:graphicOverview>

ISO 19139 introduced extensions to improve representation of browse graphics in data transfer situations:

<mri:graphicOverview>
    <mcc:MD_BrowseGraphic>
        <mcc:fileName>
            <gcx:FileName src="browseGraphicFileName"/>
        </mcc:fileName>
        <mcc:fileDescription>
            <gco:CharacterString>This form would be used when a browse graphic is distributed in a package (e.g. a zip file) 
               with the dataset or in a situation where the location of the file is known (e.g. a file in a fixed location in a folder 
               accessible by a web server).</gco:CharacterString>
        </mcc:fileDescription>
    </mcc:MD_BrowseGraphic>
</mri:graphicOverview>

and on the Web:

<mri:graphicOverview>
    <mcc:MD_BrowseGraphic>
        <mcc:fileName>
            <gcx:Anchor xlink:href="http://www.isotc211.org/bannerflash.gif">ISO TC211 Banner Image</gcx:Anchor>
        </mcc:fileName>
        <mcc:fileDescription>
            <gco:CharacterString>The ISO TC211 home page banner image.</gco:CharacterString>
        </mcc:fileDescription>
    </mcc:MD_BrowseGraphic>
</mri:graphicOverview>

This form has been superseded by the addition of the linkage element (a CI_OnlineResource) in 19115-1:

<mri:graphicOverview>
    <mcc:MD_BrowseGraphic>
        <mcc:fileName>
            <gco:CharacterString>ISO TC211 Banner Image</gco:CharacterString>
        </mcc:fileName>
        <mcc:fileDescription>
            <gco:CharacterString>The ISO TC211 home page banner image.</gco:CharacterString>
        </mcc:fileDescription>
        <mcc:linkage>
            <cit:CI_OnlineResource>
              <cit:linkage>
                 <gco:CharacterString>http://www.isotc211.org/bannerflash.gif</gco:CharacterString>
              </cit:linkage>
            </cit:CI_OnlineResource>
        </mcc:linkage>
    </mcc:MD_BrowseGraphic>
</mri:graphicOverview>

Content Standard for Digital Geospatial Metadata (FGDC)

The CSDGM Browse Graphic includes a file name (typically a URL), a description, and a type.

<browse>
      <browsen>http://www.fgdc.gov/logo.jpg</browsen>
      <browsed>FGDC Logo</browsed>
      <browset>image/jpeg</browset>
</browse>

Browse Graphics

Browse graphics and other multimedia samples are important aids to data discovery and assessment.

Concept	Description	Dialect (Fit) Paths
Browse File Name	Name of the file holding the browse graphic.	BDP /bdp:metadata/bdp:idinfo/bdp:browse/bdp:browsen CSDGM /csdgm:metadata/csdgm:idinfo/csdgm:browse/csdgm:browsen DIF /dif:DIF/dif:Multimedia_Sample/dif:File DIF-10 /dif:DIF/dif:Multimedia_Sample/dif:File ECHO /*/echo:AssociatedBrowseImages/echo:ProviderBrowseId ISO /*/gmd:identificationInfo/*/gmd:graphicOverview/gmd:MD_BrowseGraphic/gmd:fileName//* ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/*/mri:graphicOverview/mcc:MD_BrowseGraphic/mcc:fileName//* Mercury /mercury:metadata/mercury:idinfo/mercury:browse/mercury:browsen
Browse URL	Location of the browse file on the Web.	DIF /dif:DIF/dif:Multimedia_Sample/dif:URL DIF-10 /dif:DIF/dif:Multimedia_Sample/dif:URL ECHO /*/echo:AssociatedBrowseImageUrls/echo:ProviderBrowseUrl/echo:URL ECHO //OnlineResources/OnlineResource[Type='Browse'] | //OnlineResources/OnlineResource[Type='BROWSE'] | //OnlineResources/OnlineResource[Type='Thumbnail'] ISO /*/gmd:identificationInfo/*/gmd:graphicOverview/gmd:MD_BrowseGraphic/gmd:fileName/gmx:FileName/@src ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/*/mri:graphicOverview/mcc:MD_BrowseGraphic/mcc:fileName/gcx:Anchor/@xlink:href
Browse Format	Format of the multimedia sample or browse image.	BDP /bdp:metadata/bdp:idinfo/bdp:browse/bdp:browset CSDGM /csdgm:metadata/csdgm:idinfo/csdgm:browse/csdgm:browset DIF /dif:DIF/dif:Multimedia_Sample/dif:Format DIF-10 /dif:DIF/dif:Multimedia_Sample/dif:Format ECHO /*/echo:AssociatedBrowseImageUrls/echo:ProviderBrowseUrl/echo:MimeType ISO /*/gmd:identificationInfo/*/gmd:graphicOverview/gmd:MD_BrowseGraphic/gmd:fileType//* ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/*/mri:graphicOverview/mcc:MD_BrowseGraphic/mcc:fileType//*
Caption	Brief description of the multimedia sample or browse image.	DIF /dif:DIF/dif:Multimedia_Sample/dif:Caption DIF-10 /dif:DIF/dif:Multimedia_Sample/dif:Caption
Browse Description	Complete description of the multimedia sample or browse image.	BDP /bdp:metadata/bdp:idinfo/bdp:browse/bdp:browsed CSDGM /csdgm:metadata/csdgm:idinfo/csdgm:browse/csdgm:browsed DIF /dif:DIF/dif:Multimedia_Sample/dif:Description DIF-10 /dif:DIF/dif:Multimedia_Sample/dif:Description ECHO /*/echo:AssociatedBrowseImageUrls/echo:ProviderBrowseUrl/echo:Description ISO /*/gmd:identificationInfo/*/gmd:graphicOverview/gmd:MD_BrowseGraphic/gmd:fileDescription//* ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/*/mri:graphicOverview/mcc:MD_BrowseGraphic/mcc:fileDescription//*
Browse File Size	File size of browse graphic.	ECHO /*/AssociatedBrowseImageUrls/ProviderBrowseUrl/FileSize

xPath Note: The xPaths included in this table use several wildcards. // means any path, so //gmd:CI_ResponsibleParty indicates a gmd:CI_ResponsibleParty anywhere in an XML file. /*/ indicates a single level with several possible elements. This usually indicates one of several concrete realizations of an abstract object. For example /*/gmd:identificationInfo could be gmd:MD_Metadata/gmd:identificationInfo or gmi:MI_Metadata/gmd:identificationInfo and gmd:identificationInfo//*/gmd:descriptiveKeywords could be gmd:identificationInfo/gmd:MD_DataIdentification/gmd:descriptiveKeywords or gmd:identificationInfo/srv:SV_ServiceIdentification/gmd:descriptiveKeywords. Fit: The fit of the dialect path with the concept is estimated on a scale of 1 = excellent two-way fit, 2 = one-way fit or some other problem, 3 - extension required.

Metadata Implementation