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For example, a data model for a city would include a list of data layers to be included (e.g., roads, buildings, parcels, zoning), with each being specified with the type of generic spatial data model being used (e.g. raster or vector), choices of parameters such as coordinate system, and its attribute columns.
Vector data can be displayed as vector graphics used on traditional maps, whereas raster data will appear as an image that may have a blocky appearance for object boundaries. (depending on the resolution of the raster file). Vector data can be easier to register, scale, and re-project, which can simplify combining vector layers from different ...
In a field-based data model, this information is usually stored at different layers and it is harder to extract different information from various layers. This data model can be applied above the ER as in GERM model and GISER. S.Shekhar introduces direction as a spatial object and presents a solution to object-direction-based queries.
Data management, including the creation, editing, and storage of geographic data, as well as transformations such as changing coordinate systems and converting between raster and vector models. Spatial analysis, including a range of processing tools from basic queries to advanced algorithms such as network analysis and vector overlay
Overview of a data-modeling context: Data model is based on Data, Data relationship, Data semantic and Data constraint. A data model provides the details of information to be stored, and is of primary use when the final product is the generation of computer software code for an application or the preparation of a functional specification to aid a computer software make-or-buy decision.
Simple Features – specification for vector data storage (by Open Geospatial Consortium) that can be used in a GML container; GeoJSON – open, lightweight format based on JSON, used by many open source GIS packages; GeoMedia – Microsoft Access based format for spatial vector storage (by Intergraph)
Most commonly, a single spatial value would be a geometric primitive (point, line, polygon, etc.) based on the vector data model. The datatypes in most spatial databases are based on the OGC Simple Features specification for representing geometric primitives. Some spatial databases also support the storage of raster data.
A geodatabase can contain spatially referenced data in vector or raster formats, or non-spatially referenced data in tabular format. [ 27 ] [ 28 ] Each dataset contains information about any number of individual items, but typically all of the items in a dataset are of the same theme (e.g., temperature measurements, roads in a city) and have ...