Preview Function

The Preview function provides a map view of live data described by metatdata records in the geoportal. Instructions for navigating the Preview Map are provided below. The Preview can be launched from the search result page from the Preview link in a search result, through the web browser URL window, or from an embedded URL in another web page. It is also contained in the search result Details page, displaying only if the metadata describes a live data resource. The Preview page has four sections:

• Service field: URL of the service or referenced website that is loaded in the Preview window
• Embed field: html element that can be copied and input as a customization to other web pages
• Preview window: window in center of page that will display the map service, an uploaded image, the organization's website, or another element if possible. Some metadata documents do not provide enough information to populate the Preview window, or reference a service that does not support a rendering (for example, a CS-W service). The organization hosting the geoportal can control what filetypes and services are Previewable - see Configure Previewable Filetypes for details. Currently, the Preview will display ArcGIS Server services (will show a map for MapServer services), OGC WMS services, KMZ (single point and rectangle geometries), KML(single point and rectangle geometries), OGC SOS services, and ArcIMS services.
  • Note - some image services will not be preview-able because they do not advertise a compatible projection for their images in their GetCapabilities response. The service used for the Geoportal Search map uses a certain projection. When an attempt is made to preview a service on that map, the geoportal checks if valid data can be obtained for placing on the map in its given projection. In the case of feature-like services (GEORSS, KML, etc.) it is always possible because the features themselves can be projected from their original projection to a base map projection using a geometry service. However, in the case of image services (ArcIMS, WMS), obtaining project-able data is limited jpg, png, TIF cannot be reprojected through a geometry service. So if a WMS or ArcIMS Image service registered in the geoportal catalog does not support the projection of your geoportal Search map in its GetCapabilities, you will likely not be able to preview that service in the Geoportal Preview window.
• REST API metadata information: displays the REST API metadata entry.

There are four ways to access the Preview:

• When viewing a list of search results in the Search page, the search results will have a Preview link. Clicking on the Preview link will load the Preview page for that metadata record.
• If the Details link is clicked for a search result that describes live data, then the Details page will also display a Preview link at the top.
• Outside of the geoportal, you can access the Preview for a specific service by entering the following into your browser:

 http://servername/geoportal/catalog/livedata/preview.page?url=<service url>

For example:

 http://Esri_server/geoportal/catalog/livedata/preview.jsp?url=http://esri_server:8399/arcgis/services/California_Map/MapServer/WMSServer?request=GetCapabilities&service=WMS

• It is also possible to embed the Preview in another webpage. Simply copy the information from the Embed field into the webpage (can be a page outside the geoportal web application structure), and save the file.

Navigating the Preview Map

The Preview map is built using the javascript API. Navigation behavior will be like the javascript api map available as an example on the Esri resource center.

• Preview Map navigation controls, using the mouse:
  • Drag to pan
  • SHIFT + click to recenter
  • SHIFT + click + drag to define an extent in which to zoom
  • Mouse scroll forward to zoom in
  • Mouse scroll backward to zoom out
  • Double click to center and zoom in
• Preview Map navigation controls, using the keyboard:
  • Up, down, left, right Arrow keys to pan
  • + key to zoom in a level
  • - key to zoom out a level
• Map navigation buttons:
  • Full Extent button will zoom to the full extent of the world
  • Previous Extent button will take you to the extent accessed just before the current extent, if applicable
  • Next Extent button will take you forward to the extent accessed just after the current extent, if applicable
  • Base Map checkbox: the basemap configured to display on the search page will also display for WMS, GeoRSS, and KML services. The Base Map checkbox will not display for ArcIMS or ArcGIS Server services because for these types of services, the service layer obscures what would be the basemap even if the extent of the service is smaller than the extent of the basemap (this empty space renders as whitespace). The OGC-based services, in contrast, actually overlay upon the map. For OGC-based services, if you uncheck the Base Map checkbox the base map layer underneath the service being previewed will be turned off.