[edit] Data model topics
[edit] Data Architecture
Data Architecture is the design of data for use in defining the target state and the subsequent planning needed to hit the target state.
One thing you can say for sure about the quality of the information that you have created with a data model is that it lies somewhere along the scale with Trash at one enf and Truth on the other.
Data Models
Geodatabase Schemas: Data Models for GIS Users
Esri has established a set of best practices geodatabase designs for various application domains.
raster data model
See Also: vector data model
[data models] A representation of the world as a surface divided into a regular grid of cells.
SPATIAL DATA MODELS
Traditionally spatial data has been stored and presented in the form of a map. Three basic types of spatial data models have evolved for storing geographic data digitally. These are referred to as:
Vector; ...
- the GIS data model is a subset of all possible data classes that can be produced according to the previous model;
- the GIS process model aims to reach a particular goal by processing the GIS data with the tools provided by the GIS software.
Each data model is composed of collections of basic data types. Based on the analysis, it is found the data in EOSDIS will be mainly in the following basic data types:
ASCII Text: plain and formatted text for labels, descriptions or documents; ...
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Object-based data model treats spatial data as objects.
An object can represent any spatial feature: a road, a timber stand, or a hydrologic unit.
The arc-node topology data model is central to many ArcGIS vector operations. Arcs are represented with starting and ending nodes, which imparts directionality to the arcs.
The following diagram demonstrates the difference between the 3D raster and vector data models.
The user should now understand the differences in how GIS stores 3 Dimensional data, including the 2 main GIS data modeling techniques Vector and Raster.
Data Model
GIS technology employs computer software to link tabular databases to map graphics, allowing users to quickly visualize their data.
Data model
A formal method for describing data and its behavior in an application.
Data Models
There are two fundamentally different types of geographic information.
The vector model
information about points, lines, and polygons
encoded and stored as a collection of x,y coordinates ...
Data model - "Collection of concepts allowing for the representation of an environment according to arbitrary requirements" (Bonham-Carter, 1994, p. 356).
Data modeling
It is difficult to relate wetlands maps to rainfall amounts recorded at different points such as airports, television stations, and high schools.
Data modeling
It is impossible to collect data over every square meter of the Earth's surface. Therefore, samples must be taken at discrete locations.
Data Model 1. A generalized, user-defined view of the data related to applications .
2. A formal method for arranging data to mimic the behavior of the real world entities they represent.
Data Modeling and Common Content Standards
Interoperability between and among the various GIS nodes in a GIS network requires that each GIS database adheres to a similar essential data model based on widely adopted best GIS practices.
GIS data model
A GIS structure providing a framework for data manipulation and display of map data for applications such as:
(a) location verification,
(b) location correlation,
(c) locational relationships,
(d) district coding, ...
Vector data model: Divides space into discrete features, usually points, lines or polygons.
Dept. of English & Creative Writing, Bowland College, Lancaster University, Lancaster, LA1 4YT ...
data model The particular way a GIS software handles data. "1. The result of the conceptual design process. A generalized, user-defined view of the data related to applications." "2.
data model:
data is captured exclusively in raster form (pixels)
classified images may be converted to vector form for output, or for input to GIS systems
interfacing with GIS is a current development direction ...
Data model - A logical way of organizing and representing data in an information system.
Data structure - The logical and physical way of organizing digital data in a database.
[data models] A line between two points that forms a boundary. In a geometric shape, an edge forms the boundary between two faces. In an image, edges separate areas of different tones or colors.
This is a data model for storing geographic features using ArcInfo software. A coverage stores a set of thematically associated data considered to be a unit. It usually represents a single layer, such as soils, streams, roads, or land use.
Conceptual Data Model
A model that reflects information about entities of ongoing interest to the enterprise. These entities are grouped together based on their usage and applications.
Confidence Interval ...
Other than the data model itself, much of the information this section advocates for entry into your project log book can usefully be passed on to the ADS in digital form (see Section 6), ...
24 structured collection of data with software to provide access in different ways; has a data model, a data structure and an implementation (representation). database schema p.
Attribute: A fact describing an entity in a relational data model, equivalent to the column in a relational table.
Base Map: A set of topographic data displayed in map form providing a frame of reference or contextual information to the user.
data integrity Maintenance of data values according to data model and data type. For example, to maintain integrity, numeric columns will not accept alphabetic data. See referential integrity. data model 1.
semantic translator A collection of mappings between a target Information Community`s data model and a source Information Community`s data model, generally held and maintained by the target Information Community, ...
In this section the implications of vector and raster data models on encoding, storage, and analysis are discussed. The inherent statistical characterizations of mapped data and their implications in map analysis are described.
One common use of labeled contour lines is creation of 3D DEM (Digital Terrain Model) and other 3D data models. We will be seeing more and more use of 3D display in the next couple of years in GIS and computer mapping applications.
The research on object-orientation approaches has four main topics: data modeling, programming languages, database management systems and user interfaces (Maguire, 1994).
Geodatabases are object-oriented data models that are stored in a relational database management system. They enable you to store multiple feature classes and the topological relationship among them.
The simple feature data model used by OGR is very different from the topological format used by GRASS. Instead of true topology, so called 'pseudo topology' is created for data linked by v.external.
The first is from the ICSM Harmonised Data Model and is a list of Standardised Topographic Symbols. This shows the symbol, gives its name and a brief explanation of what is included in that name.
Ready-made data models make it easy to work with layers of data to observe relationships and explore new methods to represent the world around us.
In addition to their data model, most practical databases attempt to enforce a database transaction model that has desirable data integrity properties. Ideally, the database software should enforce the ACID rules: ...
Automated Polygon Processing: Software utility that transforms primitive vector boundaries and text labels into polygon data models able to support spatial analysis operations.
Raster - Common GIS data model made up of a grid of cells or pixels. Each pixel contains a single value (TWS).
Rectification - Making an image conform to a map projection system (TWS).
LABEL
An ALPHANUMERIC element, used with the VECTOR DATA MODEL, that displays attribute values or identifiers for points, lines, or polygons.
LAND COVER
The surface materials, such as crops and water, that are found in an area.
GIS readily converts data between different data models (unlike most database and statistical software).
Spatial Extension*
Share advanced raster data modeling and analysis.
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Information that describes the content, quality, condition, origin, and other characteristics of data or other pieces of information. The DC Federated Data Model provides the District government standards for metadata.
Mobile Video ...
of GIS is widely successful in government, business, and education, and it appears to have affected and improved the lives of far more people than have many theoretical advances (e.g., the theories of spatial data and of data structures, data models, ...
For example, a GIS may be used to convert a satellite image map to a vector structure by generating lines around all cells with the same classification, while determining the cell spatial relationships, such as adjacency or inclusion.
Data ...
 See also: Model, Information, GIS, Database, Software
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