72 - Describe a workflow for converting a implementing a data model in a GIS involving an Entity-Relationship (E-R) diagram and the Universal Modeling Language (UML)

Concepts

• [AM13-2] Data model and format conversion
  A data model is an abstract model that organizes elements of data and standardizes how they relate to one another and to the properties of real-world entities. The term data model can refer to two distinct but closely related concepts. In relation to the field of geoinformation the term data model refers to the set of concepts used in defining such formalizations as entities, attributes, relations, tables which is implemented by a mathematical construct for representing geographic objects or surfaces as data. There are two most frequently used data models, which are vector and raster. For example, the vector data model represents geography as collections of points, lines and polygons and more complex structures crated from these three. The raster data model represent geography as cell matrices that store numeric values. Among these two data models we also stand out data formats in which data sets can be stored. File format is a standard of encoding geographical information into a computer file. There are the following basic file formats for encoding data: For vectors: - Shapefile - Geography Markup Language (GML) - XYZ Point Cloud - GeoJSON - GeoMedia - For rasters: - GeoTIFF - IMG - JPEG2000 - Esri grid The GIS projects often require the conversion of the data formats. Data conversion is the process of moving data from one format to another, whether it is from one data model to another or from one data format to another. Data conversion is a complex process which is not only associated with changing the binary format of the file but also requires changing the structure of the data. For example, the GML data format always comes with an UML diagram, which is necessary to convert attributes stored in GML structure for example to a table of contest in a shapefile data format. In a well-managed GIS project it is important to store data in specific data model or data format. It is sometimes dictated by software capabilities and another times by team’s technical capabilities. With large amounts of geographic data used in the project it is more cost-effective to convert the data from one format to another than re-create it.
• [DA4-1] Modeling tools
  - Compare and contrast the relative merits of various textual and graphical tools for data modeling, including E-R diagrams, UML, and XML - Create conceptual, logical, and physical data models using automated software tools - Create E-R and UML diagrams of database designs