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Geography Network Content
The Geography Network provides access
to geographic content from hundreds of organizations around
the world. The content ranges from "live" map services that
can be viewed online to static geographic data sets that
can be downloaded for use with mapping software. Below is
a description of the types of content available through
the Geography Network.
Content Descriptions
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Map Service (Image):
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A map service is a dynamic map
that is published over the Internet. A Geography Network
map service is published using Internet Map Server tools
that support standard XML communication protocols, including
ESRI's ArcIMS
software ArcXML or the Open GIS Consortium Web Map Server
(WMS). The content of the map image is defined by the
publisher, while the user can interactive with the map
to change the area of interest and viewing scale. A map
service can be published as an image service or a feature
service. An image service presents the results of a map
request as a Web graphic (i.e., GIF, JPG, or PNG format).
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Map Service (Feature):
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Same as above with the following
exception. A feature service presents the results of a
map request as a stream of vector data that is interpreted
and rendered by an intelligent client application, such
as ESRI's ArcExplorer-Java Edition.
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Data Service:
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A data service is a map service
for which you can download the geographic data being displayed.
Data services enable users to perform a custom download
of the digital data they are viewing to access locally
with GIS software, such as ESRI's ArcExplorer-Java Edition.
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GeoService:
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A GeoService is an Internet service
that performs basic geoprocessing tasks, such as geocoding
or buffering. A Geography Network GeoService is published
using the standard Geography Network XML communication
protocol so that all requests for like services are handled
the same.
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Solution:
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A solution is an online application
built using Geography Network content or other Internet
hosted data. The application includes a complete user
interface and set of geographic content needed to perform
one or more tasks.
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Map Data File:
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A map data file is digital data
that is intended for use with geographic information system
(GIS) software. The data can be presented in vector format
(e.g., shapefile, coverage, DBF) or raster format (e.g.,
TIF, MrSID, JPG).
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Map Image File:
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A map image file is a finished
map that is presented in any static graphics format (e.g.,
GIF, TIF, BMP, MrSID). The content of the map image does
not change with user requests, as opposed to a map service.
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Clearinghouse:
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A clearinghouse is a Web site
that contains references and links to a variety of free
geographic data. Many clearinghouses offer geographic
data for download while other sites include metadata references
or hyperlinks to data sets that may be acquired through
other mechanisms.
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Geographic Activity:
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A geographic activity is an event
or set of events that are geographic in nature. This would
include activities such as land surveys, geographic explorations,
GIS conferences, and more. The information about these
events can be presented in many forms, such as a Web site
or map service.
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