Key to all definitions of a GIS are “where“ and “what” GIS and spatial analyses are concerned with the absolute and relative location of features as well as properties and attributes of those features. HIRE WRITERS ONLINE.
It is a computer based system to help in the collection, maintenance, storage, analysis output and distribution of spatial data and information it can also be simply defined as a tool for making and using spatial information.
Fast computer, large data storage capacities, and high-quality, large display are the foundation of most GIS. This are require for analysis, calculations, and management of information.
GIS software provides the tools to manage analyze, and effectively display and give spatial information this involves the collection and manipulation of coordinate.
This is a comprehensive set of GIS products developed by MapInfo Corporation. It provides a flexible, stand-alone product that may be used to solve many spatial analysis problem
Integrated GeoMedia offers a complete set of data entry, analysis, and output tools.
This is a product focused primarily on spatial analysis in business environment, this tool support market identification.
Open geospatial consortium, ArcGIS, QGIS, Manifold, GRASS, Microimages, Bentley map and smallworld.
Data in GIS represents a simplified view of physical entities, the roads, mountains, accident locations etc. spatial data models are objects in a spatial database plus the relationships among them we are going to explain to you two main models. Other models are object data models, Three-dimensional model and multiple models
This models uses set of coordinates and associated attribute data to define discrete objects. Groups of coordinates define the location and boundaries of discrete objects, and these coordinates data plus there attributes are used to create vector objects representing real world
Raster model defines the world as a regular set of cells in a grid pattern. These cells are square and evenly spaced in the x and y directions the phenomena or entities of interests are represented by attribute values associated with cell location.
Geographic information system are different from other information systems. These spatial data includes coordinates that define the location shape, and extent of geographic objects.to effectively use it, we must understand how coordinates systems are established for the Earth how they are measured on earths curving surface and how they are converted to use on flat maps either digital or paper. Most commonly used map projection are the lambert conformal conic and transverse Mercator
Geodesy-The science of measuring the shape of the earth and map projections
Datum-approximation of the earth’ surface against which positional measurements are made for computing location.
Spatial data entry and editing are frequent activities for many users. A large number of coordinates is needed to represent features in it, and each coordinate value must be entered into the database this is slow and tiring. Most spatial data sources maybe categorized as hardcopy or digital. Hard copy dorms are drawn written or printed documents this maps and documents.
Global navigation satellite systems and coordinate surveying in GIS
GNSS are satellite-based technologies that give a precise positional information, day or night, in most weather and terrain conditions. GNSS technologies may help navigate and track moving objects large enough to carry a receiver. Receives shrink in size, weight, and power requirements each year. Coordinate surveying is often combined with precise GNSS measurements because both methods are important.
GIS Basic spatial analysis
Spatial data analysis is application of operations to coordinate and related attribute data, often to solve a problem, for example, to identify high crime areas or to generate list of road segments that need repaving. Spatial data analysis involves using data from one layers to create output. The analysis may consist single operation or many operation that intergrate input data from many layers to create desired output.
GIS Spatial estimation
Interpolation and spatial prediction allow us to estimate values or locations where they have not been measured. This methods are commonly used because the budget is limited samples may be lost or found wanting, or because time has passed since data collection. We may also interpolate when converting between the models.
GIS Data standards, data quality
Data standards, data accuracy assessment, and data documentation are among the most important activities. We cannot effectively use spatial data if we do not know its Quality and the efficient distribution of spatial data depend on a common understanding of data content
New developments in GIS
As GNSS use grows and manufacturing methods improve, single chip GNSS systems have emerged and this chips are decreasing in size smaller than postage stamps are available including some that maybe integrated into common electronics.
GNSS is also being combined with new advances in ground based laser scanning to increase the scope, accuracy, and efficiency of spatial data collection. Three dimensional scanning devices have been developed that measure horizontal and vertical location of features.
New datum realizations will be calculated, based on improved measurements. Datum shifts among ITRF based datum will remain small, but planned datum adjustments for the NAD83 datum over the next decade may ray result quite large shifts.
More satellites, higher spatial and temporal resolutions, improved digital cameras, and new sensor platforms will all increase the array of available data.
This software is different from other software’s since it is distributed freely. This software is designed not to be restricted to a specific operating system or other technology, that there can be no royalties and no explicit discrimination against fields of persons or groups.
Other trends are Hybrid model and open standard GIS.
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