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/>
        </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="http://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://browseGraphicAnchor"/>
        </mcc:fileName>
        <mcc:fileDescription>
            <gco:CharacterString>This form would be used when a browse graphic is in a web accessible location.</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>Name of the file</gco:CharacterString>
        </mcc:fileName>
        <mcc:fileDescription>
            <gco:CharacterString>This form would be used in ISO 19115-1 when a browse graphic is in a web accessible location.</gco:CharacterString>
        </mcc:fileDescription>
        <mcc:linkage>
            <cit:CI_OnlineResource>
              <cit:linkage></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>/fgdc:metadata/fgdc:idinfo/fgdc:browse/fgdc:browsen</browsen>
      <browsed>/fgdc:metadata/fgdc:idinfo/fgdc:browse/fgdc:browsed</browsed>
      <browset>/fgdc:metadata/fgdc:idinfo/fgdc:browse/fgdc:browset</browset>
    </browse>

Crosswalks

Concept	Description	Dialect (Fit) Paths
Browse File Name	Name of the file holding the browse graphic.	DIF /dif:DIF/dif:Multimedia_Sample/dif:File ECHO /*/echo:AssociatedBrowseImages/echo:ProviderBrowseId FGDC /fgdc:metadata/fgdc:idinfo/fgdc:browse/fgdc:browsen ISO /*/gmd:identificationInfo/gmd:MD_DataIdentification/gmd:graphicOverview/gmd:MD_BrowseGraphic/gmd:fileName/gco:CharacterString ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/*/mri:graphicOverview/mcc:MD_BrowseGraphic/mcc:fileName/gco:CharacterString
URL	Location of the browse file on the Web.	DIF /dif:DIF/dif:Multimedia_Sample/dif:URL ECHO /*/echo:AssociatedBrowseImageUrls/echo:ProviderBrowseUrl/echo:URL ISO /*/gmd:identificationInfo/gmd:MD_DataIdentification/gmd:graphicOverview/gmd:MD_BrowseGraphic/gmd:fileName/@src ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/*/mri:graphicOverview/mcc:MD_BrowseGraphic/mcc:fileName/gcx:Anchor/@xlink:href
Format	Format of the multimedia sample or browse image.	DIF /dif:DIF/dif:Multimedia_Sample/dif:Format ECHO /*/echo:AssociatedBrowseImageUrls/echo:ProviderBrowseUrl/echo:MimeType FGDC /fgdc:metadata/fgdc:idinfo/fgdc:browse/fgdc:browset ISO /*/gmd:identificationInfo/gmd:MD_DataIdentification/gmd:graphicOverview/gmd:MD_BrowseGraphic/gmd:fileType/gco:CharacterString ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/*/mri:graphicOverview/mcc:MD_BrowseGraphic/mcc:fileType/gco:CharacterString
Caption	Brief description of the multimedia sample or browse image.	DIF /dif:DIF/dif:Multimedia_Sample/dif:Caption
Description	Complete description of the multimedia sample or browse image.	DIF /dif:DIF/dif:Multimedia_Sample/dif:Description ECHO /*/echo:AssociatedBrowseImageUrls/echo:ProviderBrowseUrl/echo:Description FGDC /fgdc:metadata/fgdc:idinfo/fgdc:browse/fgdc:browsed ISO /*/gmd:identificationInfo/gmd:MD_DataIdentification/gmd:graphicOverview/gmd:MD_BrowseGraphic/gmd:fileDescription/gco:CharacterString ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/*/mri:graphicOverview/mcc:MD_BrowseGraphic/mcc:fileDescription/gco:CharacterString

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.