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english:glossary:dataformat

Data (Format)

We distinguish between data that carry attributes, or non-spatial characteristics of objects or entities (a name, a quality, a quantity), and spatial or geographical data describing the geometry of objects, their shapes and locations.

The data are available as files in different formats that are possible to download and modify, before putting them online. Increasingly, data are available in the form of geographic Web Services that enable data exchange between applications.

Attribute data are usually collected in tables composed of rows and columns. These tables can correspond from the perspective of Information Technology with very different file formats that can be opened with spreadsheets like Excel or OpenOffice Calc. The most common file formats are CSV (Comma-Separated Values), Excel spreadsheet (.xls or .xlsx), DBF, and Json.

There are numerous formats of geographic data files, but the most common on the Geoweb are following three: KML/KMZ (Google), GeoJson (Open Source), Shape Format (ESRI proprietary file format). The newest formats, linked to at http://en.wikipedia.org/wiki/XML, store attributes and descriptive geometry in the same files just as KML/KMZ or GeoJson do.

With the development of the Internet, data exchange is done less and less through files, and increasingly through web services that enable the exchange of data across servers. There are many web services related to data formats. The most common are the services WMS and WFS.

When geographical data are in the form of points and the coordinates are reduced to a pair (x, y), x for the longitude and y for the latitude, the attribute formats CSV or Excel are used to store them in two columns .

It is also possible to store the coordinates of digital photographs directly into the image metadata in EXIF format.
[French: Données (Format des)

english/glossary/dataformat.txt · Dernière modification : //26/08/2018 11:02// de joliveau

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