The Geospatial Search
Engine (GSE) is a web application created by the Western Wildland
Environmental Threat Assessment Center (WWETAC). GSE provides
a search engine for Geographic Information System (GIS) map servers
and layers. GSE supports web map services (WMS), ArcGIS services,
ArcIMS services, and shapefiles for download. The application
is hosted in the Amazon Web Services cloud and is available at
This system combines
a searchable database of GIS map servers and layers, with a web
crawler for both locating new data and updating existing data.
GSE is currently a standalone application, but there are plans
to build a user friendly API to allow further access to the search
The GSE user interface
is built using open source components such as Ext
JS, GeoExt, and OpenLayers.
The Google Web Search API is integrated to obtain web search results
based on user specified terms. The user interface consists of
the following parts.
Panel - The left side of the interface is used for
specifying search terms and retrieving a list of map servers
and layers. For shapefiles, a web page link is provided so
that the user may review the web page containing shapefiles
available to download. The GSE database is searched using
the specified terms, and results are returned to the user
in a tree view. There is a separate node in the tree view
for each of the 4 server types (WMS, ArcGIS Server, ArcIMS,
and Shapefile). Below the server type node is a node for each
map server, and each map server has nodes for each layer that
meets the search criteria. It is possible to have a map server
node with no layer sub nodes. This occurs when the map server
abstract or keywords contain the search terms but none of
the layer abstracts or keywords contain the terms. As the
user selects nodes in the tree view, the total number of layers
and the number of layers that meet the search criteria are
displayed in the lower right corner of the search panel.
The View button below the search panel will either display
a preview map of the selected layer, or if a shapefile server
is selected, open the web page.
Layers - The Get All Layers button will retrieve
a list of all layers for the selected map server, rather than
just the layers that meet the search criteria. The layers
will be listed in the layer list panel on the right side of
the application interface.
List Panel - The right side of the interface allows
the user to specify a known URL and retrieve available map
layers. When a URL is specified that is not found in the database,
the GSE application will contact the map server to retrieve
metadata and add this server to the database. This allows
for a convenient method of manually adding map servers to
the database. The list of layers is returned to the user and
displayed in a table with Title and Description columns. By
clicking on the column headers you can sort the layers by
Title or Description.
- The Preview button at the bottom of the layer list panel
displays a preview map for the selected layer. This map contains
a background map for reference purposes in addition to a map
of the selected layer. On the right side of the map is a plus
symbol. Clicking this symbol opens a small window allowing
the user to turn layers on and off. On the left side of the
map is a navigation bar, allowing the user to pan and zoom
the map. Panning can also be accomplished by clicking and
dragging the mouse. Holding the shift key down while clicking
and dragging on the map will draw a rectangle defining an
area to zoom to. The mouse wheel can also be used for zooming
in and out. The user can also double-click a layer in the
list to display the preview map. Note that the GSE application
currently only displays preview maps for layers that support
the following spatial reference systems:
- EPSG 4326 (latitude/longitude
based on the WGS84 datum)
- EPSG 900913/3857/102113/3785/102100
- More Info
- The More Info button at the bottom of the layer list panel
will open a small window displaying the following additional
information for the selected layer:
Name. This is
the unique name for the layer and is required for outside
access to the layer.
description of the layer.
specified for the layer.
Lat Long Bounding
Box. The extent of the layer in latitude/longitude units.
Reference Systems. A comma delimited list of EPSG codes
for spatial reference systems supported by the layer.
Threat Assessment Center
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