Category Archives: GIS

GPS Accuracy and WAAS

Posted on July 13, 2008 by Rashid Faridi

To determine an object’s location, the GPS system must receive a radio signal from at least three satellites. Since each satellite emits a unique signal, the receiver can then match the signal to the satellite and its orbital position. Distance … Continue reading →

Posted in GIS, GPS, Remote Sensing 101 | Tagged | 3 Comments

Topology and Layers in GIS

Posted on June 27, 2008 by Rashid Faridi

TOPOLOGY & LAYERS (THEMES) Topology refers to the spatial relationships between geographic features. It describes the relationships between connecting or adjacent coverage features. Topological relationships are built from simple elements into complex elements: points (simplest elements), arcs (sets of connected … Continue reading →

Posted in GIS, Remote Sensing 101 | 3 Comments

GIS DATA TYPES & DATA MODELS

Posted on June 22, 2008 by Rashid Faridi

Although the two terms, data and information, are often used indiscriminately, they both have a specific meaning. Data can bedescribed as different observations, which are collected and stored. Information is that data, which is useful in answering queries or solving … Continue reading →

Posted in GIS | 8 Comments

ERRORS IN GIS

Posted on June 20, 2008 by Rashid Faridi

No map is perfect. Even the most accurate maps created by a GIS have some deficiencies. These deficiencies occur due to “Errors” that may have taken place at different stages of GIS implementation. These errors reduce the accuracy of the … Continue reading →

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