<p>Geographic Information Systems (GIS) are by their nature data
driven. The data comes in a wide variety of raster and vector formats.
Rasters hold raw, continuous data recorded striaght from the real
world. An example is Satellite/aerial imagery, this is a commonly held
in an open format with broad support, such as <a href="http://en.wikipedia.org/wiki/GeoTIFF" onclick="javascript:pageTracker._trackPageview('/outbound/article/en.wikipedia.org');">GeoTIFF</a> or <a href="http://en.wikipedia.org/wiki/JPEG" onclick="javascript:pageTracker._trackPageview('/outbound/article/en.wikipedia.org');">GeoJPEG</a>.</p>
<p><a href="http://en.wikipedia.org/wiki/GIS_file_formats#Vector_formats" onclick="javascript:pageTracker._trackPageview('/outbound/article/en.wikipedia.org');">Vector formats</a>
hold refined, discrete data, which has been manually traced or
otherwise derived other data sources. Examples include building
outlines, contours, road routes, pipe networks land land parcels and
locations. Vector data is usually traced or derived, at great expense
from raster data, to encode business information - as a result it’s
usually highly valuable.</p>
<p>Unfortunately, there are many GIS vector file formats, and most are
proprietary. They can only be used to their full in their native
software. Three of the biggest are AutoCAD <a href="http://en.wikipedia.org/wiki/AutoCAD_DXF" onclick="javascript:pageTracker._trackPageview('/outbound/article/en.wikipedia.org');">DXF</a>, MapInfo <a href="http://en.wikipedia.org/wiki/MapInfo_TAB_format" onclick="javascript:pageTracker._trackPageview('/outbound/article/en.wikipedia.org');">TAB</a> and ArcGIS <a href="http://en.wikipedia.org/w/index.php?title=Personal_Geodatabase" onclick="javascript:pageTracker._trackPageview('/outbound/article/en.wikipedia.org');">Personal Geodatabase</a>. One vector format is unique - both an open standard, and in wide use: Shapefile.</p>
<p>Texto completo pode ser encontrado no blog <b>Misspelled nemesis club</b></p><p><a href="http://moreati.org.uk/blog/2009/03/01/shapefile-20-manifesto/">http://moreati.org.uk/blog/2009/03/01/shapefile-20-manifesto/</a><br>
</p><br>-- <br><a href="http://thusbeginstheweb.blogspot.com/">http://thusbeginstheweb.blogspot.com/</a><br>