Archive for the ‘GIS’ Category

4 Jul 2009

by M Rajesh

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GIS

Satellite Navigation Systems

Navigation Requirements
• Reliable Positioning System with Quality of Service
• Positioning Service with Integrity information about the displayed Position
• High coverage in Urban Environments
• Good Accuracy for both Horizontal and Vertical Positions
• “Wearable” GNSS receiver
• Connectable GNSS Receiver to other on person equipment
The following table summarises the main User Needs for the different Sector and Market segments. The most important parameters are [...]

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4 Jul 2009

by M Rajesh

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GIS

Object Based Vector Data Model

 This new model uses objects to represent and organize spatial features.
 The geometry (spatial data) of a feature is stored as an attribute along with other attributes in a record.
 Objects can have properties and methods to capture characteristics of real-world objects.
 Object-based data model treats spatial data as objects.
 An object can represent any spatial feature: a road, [...]

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4 Jul 2009

by M Rajesh

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GIS

Geoprocessing

• Is the center of GIS, most every processing in GIS we performed is a Geoprocesing.
• Definition (a GIS operation that takes one or more input datasets, performs one or more operations, returns one or more output layers (results))
o Four ways: dialog tool box, command line, model, script
o Model is a workflow chart that can execute multiple processes as [...]

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4 Jul 2009

by M Rajesh

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GIS

3D analysis

• Difference between 3D and 2D data
• 3D analyst include ArcScene and ArcGlobe, which used for visualizing 3D data, creating and analyzing 2D and 3D surfaces
• Type of 3D data
o 3D-surface (raster and TIN)
o 3D-feature (shapefile and geodatabase feature class), has a field of PointZ, PolygonZ, PolylineZ in the attribute table.
o Create TIN from vector data (point, lines, polygons)
o Mass points are [...]

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4 Jul 2009

by M Rajesh

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GIS

Geostatistical analysis

• What is the geostatistical analysis?
• Explore data (why? methods: histogram, voronoi map, normal QQplot, general QQPlot, trend analysis, semivariogram/covariance cloud, crosscovariance cloud)
• Methods of interpolation (global and local, deterministic and geostatisctical, exact and inexact, nodirectional and ansotropy)
1. IDW (characteristics)
2. Global polynomial
3. Local polynomial
4. Radial Basis Functions (or spline)
5. Kridging (assumption, assessment of prediction errors)
 Ordinary, universal, simple, indicator, cokridging
• Output maps (prediction map, standard [...]

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4 Jul 2009

by M Rajesh

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GIS

Spatial analysis

Vector analysis
• Two sets of vector analysis tools in ArcToolBox
o For shapefile, feature class, table
o For coverage
• Extract (clip, select, split), Overlay (erase, identify, intersect, union, update), Proximity (buffer, near, point distance, thiessen polygon)
Raster analysis
• Spatial Analyst Tools (includes groundwater and hydrology tools) and Spatial Analyst extension
• Mapping distance (straight line, allocation function, cost weighted distance, shortest path), mapping density, surface [...]

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4 Jul 2009

by M Rajesh

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GIS

Basic GIS Topics – Review of basic GIS

• What is GIS?
• 3 components (computer system, spatially referenced data, people)
• Spatially reference data or geographic data (geospatial data, attribute data, metadata)
• Geospatial data:
o Characteristics of spatial data (mappable, discrete or continuous, spatial relationships)
o GIS is a simplified view of the real world (discrete or continuous), problems still exist (dynamic and static, identification of discrete or continuous features, scale, fuzzy)
o [...]

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11 Jun 2009

by M Rajesh

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GIS

What is GIS?

GIS allows us to view, understand, question, interpret, and visualize data in many ways that reveal relationships, patterns, and trends in the form of maps, globes, reports, and charts.
A GIS helps you answer questions and solve problems by looking at your data in a way that is quickly understood and easily shared.
GIS technology can be [...]

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22 Mar 2009

by M Rajesh

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GIS

WebDesign – JavaScript – Adding PDF Icon to Links

First Place an icon file in images folder, then put the following code in <head> tag
<script src=”http://jqueryjs.googlecode.com/files/jquery-1.3.2.min.js”></script>
<script type=”text/javascript”>
$(document).ready(function() {
$(’a[href^=mailto:]‘).addClass(’mailto’);
$(’a[href$=.pdf]‘).addClass(’pdflink’);
$(’a[href^=http][href*=henry]‘).addClass(’henrylink’);
});
</script>
<style>
.mailto {
background: url(images/mail.png) no-repeat right top;
padding-right: 18px;
}
.pdflink {
background: url(images/pdf_button.png) no-repeat right top;
padding-right: 18px;
}
</style>

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6 Mar 2009

by M Rajesh

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GIS

RFID

Introduction
RFID (Radio Rrequency IDentification) is a technology that incorporates the use of electromagnetic or electrostatic coupling in the radio frequency (RF) portion of the electromagnetic spectrum to uniquely identify an object, animal, or person. RFID is coming into increasing use in industry as an alternative to the bar code. The advantage of RFID is that [...]

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