【正文】 Text information inside SVG is still text and can be searchable, while text information inside the raster file bees integrated into the image and is no longer recognized as text. SVG is also particularly suitable for displaying intelligent maps, because geometric objects such as points, lines, and polygons are recognized as such and are identifiable. Raster images on the other hand contain information about every pixel, and points, lines and polygons that are no longer recognizable. Therefore, the user can directly work with spatial features on an SVG but not on a raster graphic image (Peng and Zhang, 2021). SVG is also based on XML and therefore conforms to other XMLbased standards and technologies, such as XML Namespace, XLink, and XPointer. XLink and XPointer allow for linking from within SVG files to other files on the Web, like a GML data element, HTML pages or other SVG files (Boye, 1999). . Extensible stylesheet language transformation—XSLT XSLT is a language that enables the user to convert XML documents into other XML documents or into almost any form an application or a user needs. XSLT provides an easy, W3C sanctioned, way to convert XML documents that conform to a schema into documents that conform to another, enabling the sharing of information between different systems. From another perspective XSLT is a programming language that describes the way and the methods to be followed for the transformation of a wellformed tree structure of an XML document to another. XSLT is not the only way to achieve these goals。 column=39。 column=39。? image pixel id=39。039。039。039。 there are alternative ways to transform XML documents but XSLT has prevailed. The fact that XSLT is a W3C standard implies that XSLT plies with the specifications published by the W3C or those that will be announced in the future (Clark, 1999). Furthermore, the nonproprietary status of the specification and the platform independency, guarantee the prospects and the integrity of the specification. In addition, the fact that the XSLT document transformation instructions are stored as an XML document is an advantage since there is no need for using another syntax. The abovementioned characteristics justify the popularity of XSLT when it es to XML transformation (DuCharme, 2021). . Data model encoding The accurate representation of the plexity of the real world has been one of the fundamental problems in Geomatics. In order to address this issue the GIS munity has introduced a number of ways for modeling real world data. In a vector model, reality is perceived as an aggregation of discrete entities defined by their geometry, topology and thematic attributes. Another popular way to describe real world phenomena is by using raster structures that can sufficiently describe continuous/field data. The raster model in its basic form is considered as a rectangular array of equally spaced pixels. Each pixel can be defined uniquely inside the array through i,j coordinates. The values stored in the pixels of the array depend on the phenomenon and can be from elevation or temperature to the reflectance of light for part of thespectrum. . The XML approach XML enables domain experts to create properly structured formats, which can serve the storage and exchange of a wide variety of data types. Apart from that XML itself can store efficiently various types of data and it can easily describe continuous data using a tablebased mapping. The tablebased mapping is used to model XML documents as a single table or set of tables (Fig. 1). tableholder table1 row column1.../column1 column2.../column2 ... /row row ... /row ... /table1 table2 ... /table2 ... /tableholder Fig. 1. Tablebased mapping of field data. This general form can be modified accordingly in order to acmodate the description of different phenomena. For instance the description of a threeband raster image could be achieved in the way shown in Fig. 2. A problem easily solved through XML is whether the auxiliary data should be stored as child elements or as attributes, as well as the names to be used for each element or attribute. In addition, developers who use tablebased mappings often include table and column metadata either at the beginning of the document or as attributes of each table or column element. For image metadata one could store pixel size, date and conditions of capture, details of the camera used, etc. Using this method efficient description, storage and exchange of fieldtype geographic data can be achieved utilizing open standards and promoting interoperability (Bourret, 2021). image band1 pixel id=0 row=0 column=0 r201/r g171/g b81/b /pixel pixel id=1 row=0 column=1 r203/r g175/g b78/b /pixel pixel ............ /pixel ............ /band1 band2 ............ /band2 band3 ............ /band3 /image Fig. 2. Description of a threeband raster image. Apart from continuous data, XML can easily encode data modeled as vectors. An XML schema is developed describing the definitions of geometric primitives. In fact that is what OGC provides through GML, which is an XMLbased specification designed to describe vector data. . The GML approach GML has been a turning point in Geomatics to the extent that many national and private anizations have already adopted this format. GML specification introduced a number of new ponents improving vector data encoding (Cox et al., 2021). GML provides only three core schemas (, geometry. xsd and ) whereas in GML there are 28 core schemas. This version supports new geometry types including Arc, Circle, CubicSpline, Ring, OrientableCurve, OrientableSuface, Solid, and the aggregates CompositeCurve, CompositeSurfa