gvSIG-Desktop 1.1. Manual de usuario.

ADL Gazetter Protocol: Standard defining how the communication between ADL gazetteer clients and servers must be.

ADL GCS (ADL Gazetteer Content Standard): Although it is not an official standard it is the de facto set of rules used to defined the relationship between a toponym and its coordinates. It can supply other attributes such as the region where the toponym is settled, or the nature of this datum.

ANZLIC (Australian and New Zealand Land Information Council): Is the organization in charge of the development of the SDI in these two countries.

Band: Frequency interval from the electromagnetic spectrum. For example, the first band of the TM sensor is defined in the range of 0.45-.052 mm.

Database: Set of data structured in order to enable the storage, consultation and upgrading in a computer system. The relational database is a concrete case in which the information is organized in relations (often known as “tables”). Relations are a set of tuples (“records”) and a tuple integrates information about an element in a set of fields (one field for each attribute of the element); if two tables share a field containing values within the same domain then it is possible to apply a union operation. The union links the tuples according on the values in the linking field.

BMP: Acronym for Bit Map Picture; is a basic image format. It is simple and pretty normalized; it is a excellent format for sharing data and fast when analyzing and processing images. However, since it is not compressed it does not improve the transmission and disk accessing times. BMP is often used win RGB 24 bits.

CAD: Acronym for Computer Assistant Design. It is an automatic system oriented to design, draw and graphical visualization.

Cartography: Set of operations and processes that take part in the creation, edition and analysis of maps.

catalogue, Service of: Allows the publication and searching of information (metadata) describing data (cartography), services, applications and any other kind of resources. The catalogue services are necessary to supply search and invocation capabilities over registered resources within an SDI. A Open Geospatial Consortium spec establishes how a Catalogue Service must be standard and interoperable.

CatMDEdit: Is a computer application for creating and editing geographic metadata based upon the “OSI19115. Geographic Information – Metadata” norm. Among its features, it is an open-source project, multiplatform (Windows / UNIX) and multilingual (Spanish and English) as well.

CEN (European Committee of Standarization): Official organization for normalization of the European Union. Replaces country specific techniques by common rules for the whole Union in collaboration with international organizations and its members in Europe (CENELEC for electronics and ETSI for telecommunications).

CEN TC 287 (Technical Committee of Geographic Information): Set of standards for manipulating geographical information (approximately 20).

Clearinghouse: A distributed service for metadata about geospatial data locating. Allows to search in one or several nodes or servers that have been registered in the Clearinghouse of the Internet. It is the term used by FGDC, equivalent to the OGC’s Catalogue Service.

CNIDR z39.50 Server (clearinghouse for Networked Information Discovery and Retrieval): z39.50 server, also known as zDist.

Compression: Technique for reducing the amount of bits needed for storing or transmitting information. There are lossless or destructive compressions (for instance, GIF and JPG for the digital images respectively).

Coordinate: Value defining the position in a reference system. The coordinates can be lineal (Cartesian) or polar (spherical), depending on the reference system.

Cota en ingles es Height que se autodefine CSDGM (Content Standard for Digital Geospatial Metadata: Determines the metadata that exists in a geographical position and how to access to them. It does explain neither how to organize the data in a computer nor which software to use.

Datum: Geometric reference system used to numerically express the geodesic position of a point over the terrain. Each datum is defined according of an ellipsoid and a point where the ellipsoid and the Earth are tangent. In Spain for example, the datum uses the Hayford (or International 1924) ellipsoid and the tangency point is Postdam (Germany).

DublinCore: Set of metadata elements created to make the electronic resource discovery easier. ebRIM (ebXML Registry Information Model): Specifies a set of services that make the communication between companies easier using ebXML.

ebRS (ebXML Registry: Services and Protocols): Defines the services that the ebXML Registry and other related protocols offer.

ebXML (electronic Business XML): Is a Standard that defines an XML-document format for sharing information between companies.

Element of a metadata: Discrete metadata unit. Entity of a metadat**: Set of elements describing the same aspect of the data.

Ellipsoid: Simplified description of the Earth shape: the ellipsoids are defined by equatorial and polar radiuses.

EPSG: European Petroleum Survey Group.

Scale: Constant relation between a distance in a map and the corresponding real distance.

FGDC (Federal Geographic Data Committee): Organization in charge of developing the National Spatial Data Infrastructure (NSDI) of the United States of America.

Geodesy: The science that studies the shape of the Earch in the gravitational field.

Geoid: Is the level surface, equipotential in the gravitational field, which adopts an irregular three-dimensional spheroid. Due to the dependency on the mass distribution inside the Earth, it is impossible to represent it mathematically. The mathematical shape used to do it is the ellipsoid that approximately fits better the Earth shape. The geoid is coincident with the mean ocean surface when they are quiet, virtually extended for the continents land.

Georreference: The art of assigning geographic coordinates to an object or structure. This concept applied to a digital image involves a set of geometric operations that allow assigning to each image pixel a pair of coordinates (x, y) in a projection system.

GIF: Graphic Interchange Format. Developed by CompuServe to provide a standard and platform-independent format. The GIF format is limited to a maximum of 256 colours. It is a reasonable limitation since most of the PC screens support 256 colours at most. In general, GIF is recommended for simple images. When the background has textures they are not useful because the computer tries to find the closest colour, and some distortions may appear in this process and the result is an inaccurate displaying for the image.

GPS: Acronym for global positioning system. It refers to the system by means of which it is possible to approximately calculate a position in the Earth using a signal received from several satellites (called the GPS constellation) simultaneously.

Grid: Is a net composed by two or more series of arcs in which the member of each series intersects with the members of the other series in an algorithmic way.

gvSIG: A Geographical Information handling tool. Features a user-friendly interface, an agile access to the most common vector and raster formats. It can integrate local and remote (the Internet) data through connections following some protocols specified by the Open Geospatial Consortium.

Spindle: Part of a sphere limited by two meridians or maximum circles. In the UTM projection each spindle is defined by two meridians separated by a distance of 6 degrees (for a total circle round of 360 degrees) and by two parallels of 80 degrees latitude North and South.

SDI: An SDI (Spatial Data Infrastructure) is a computer system integrated by a set of resources (catalogues, servers, programs, data, applications, web pages, and so on), for manage Geographic Information (maps, satellite images, toponymes, etc.), available from the Internet, that follow a set of interoperational capacity conditions (rules, specifications, protocols, interfaces, etc) that allow an user to use them using a simple browser and combine then for his/her needs.

IDEE: Acronym for Infraestructura de Datos Espaciales de España, or Spanish Spatial Data Infrastructure. The goal of the IDEE is to integrate through Internet the geographic data, metadata, services and information produced in Spain. So, any potential can identify, select, and access to these resources from the IDEE’s site where any node and other site of other geographic information producers of local, regional or even national wide areas available in Spain.

Digital Image: Graphical representation of an object which is, in fact, a regular matrix that is a collection of a reflectance values. The reflectance values are usually measured by sensors of a specific range of light wavelengths; examples of these sensors are those aerial-transported such are aircrafts or satellites or those integrated in a scanner used to digitalize printed documents.

Nomenclator Service: Offers the possibility of locating a geographic place by its name. It is defined as a service that receives an input that is the name of the place (toponym), with the common possibilities: exact match, starting with, contains, etc. and returns the location, by means of the coordinates, of the place. Additionally, the query by name also handles other criteria such as the spatial extension where to look up, or the type of the place (river, mountain, towns …). If one or more occurrences are found, the service supplies a list of the places found with any additional attribute describing it for the user can choose the desired one. There is an Open Geospatial Consortium spec describing how a Nomenclator Service must be to be standard and interoperable.