From
Wikipedia:
The OpenGIS Web Feature Service Interface Standard (WFS) is an interface allowing requests for geographical features across the web being highly interoperable.
It uses the
XML-based Geographic Markup Language (GML) for data exchange. This means that instead of returning an
image, as WMS services (described below) do, the service returns a GML file containing both the geometry and the attribute.
More...
From
Wikipedia:
An OGC Web Map Service (WMS) produces maps of spatially referenced data dynamically from geographic information.
This International Standard defines a "map" to be a portrayal of geographic information as a digital image file
suitable for display on a computer screen. A map is not the data itself. WMS-produced maps are generally rendered in
a pictorial format such as PNG, GIF or JPEG, or occasionally as vector-based graphical elements in Scalable Vector
Graphics (SVG) or Web Computer Graphics Metafile (WebCGM) formats.
More...
This International Standard defines three operations: one returns service-level metadata; another returns a map
whose geographic and dimensional parameters are well-defined; and an optional third operation returns information about
particular features shown on a map. Web Map Service operations can be invoked using a standard web browser by submitting
requests in the form of Uniform Resource Locators (URLs). The content of such URLs depends on which operation is requested.
In particular, when requesting a map the URL indicates what information is to be shown on the map, what portion of the Earth
is to be mapped, the desired coordinate reference system, and the output image width and height. When two or more maps are
produced with the same geographic parameters and output size, the results can be accurately overlaid to produce a composite
map. The use of image formats that support transparent backgrounds (e.g., GIF or PNG) allows underlying maps to be visible.
Furthermore, individual maps can be requested from different servers. The Web Map Service thus enables the creation of a
network of distributed map servers from which clients can build customized maps.
The Open Geospatial Consortium(OGC), Inc.
WMS 1.1.0 specification (PDF)
WMS 1.1.1 specification (PDF)
OGC Network Web Mapping Service Portal
Useful WMS Instructions/Cookbooks
Example WMS Clients
WMS Tutorials
From
The
Metadata Primer:
Simply defined, metadata is "data about data." Used in the context of
digital spatial data, metadata is the background information which describes
the content, quality, condition, and other appropriate characteristics
of the data. Paper maps contain metadata, primarily as part of the map
legend. In this form, metadata is readily apparent and easily transferred
between map producers and map users. When map data are in a digital
form, metadata is equally as important, but its development and maintenance
often require a more conscious effort on the part of data producers
and the chain of subsequent users who may modify the data to suit their
particular needs.
Metadata can help preserve the usefulness of a data set within an organization.
If metadata is created according to the
federal
metadata standard and contributed to an
NSDI
Clearinghouse, it becomes possible for other users to search for
and find this information and its related data effectively.
... still unsure?
Try
Metadata
in plain language or the
unofficial
FAQ on FGDC Metadata
This page leads to summaries of most of the known metadata tools used
for documenting geospatial data and serving geospatial metadata. It
includes tools for entering and editing metadata and utilities for preprocessing,
extracting, postprocessing, and validating metadata. Most of these tools
were designed to help complete Content Standards for Digital Geospatial
Metadata (CSDGM) metadata, but several have been tuned to produce specific
local metadata profiles.
Soup to nuts on metadata issues, resources, tools, and getting started
for the metadata novice to the metadata maestro.
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