GIS & Remote Sensing

Vector Data Model As discussed in raster data article that earth surface features can be created in both raster and vector format as per requirement of user.  For example wetland mapping feature such as pond can be created in both data formats, in vector as polygon and grid/pixels format in raster.  Vector Data Model is an object based approach to the representation of real world features. This data model is best suited to represent discreet objects.  In this method the entire earth surface feature including man-made and natural can be represented by only three entities in GIS . These entities name- Point Line  Polygon In this all the features in which only locations is presented than Point entity used for representation in GIS software , However for representation of all linear features, line entity used in GIS tools .  To represent any enclosed feature of earth and representation of any feature which has area entity, in that case, polygon entity is used in vector data.

Raster Data Formats used in GIS and Remote Sensing Earth surface features including man-made features can be represented in GIS and remote sensing processes as spatial data. Spatial Data in GIS and remote sensing has two primary data formats to create information Raster Vector Earliest GIS software was either Raster based or Vector based, but now most of the GIS software has data processing capabilities in both formats. Advances in computer technology have largely eliminated the boundaries between Raster and Vector data for GIS applications .  An integrated raster and vector data working environment provides many more opportunities as one can combine the mathematical methods and simulations suitable for both the formats in the analysis. Both formats have their advantages and disadvantages. RASTER DATA Raster data have become the primary source of spatial data in geographic databases and are used increasingly in a wide variety of GIS applications .   Raster data def

Geo-Spatial Data - Spatial and Non-Spatial Data Data is raw form of information, which is given to the computer for processing. However, database is an organized collection of related data. Database should be integrated, structured and shared.  So here we can say that GIS is both a database system with specific capabilities for spatially referenced data as well as a set of operations for working with the data.  GIS database consist of sets of information called Layers. Each layer represents a particular type/class of geographic data. For example, one layer may include information on the road network in an area as line layer .  Another layer may contain information on the land use in that area as polygon layer , while another records soil, elevation etc. The GIS can combine these layers into one image, showing how the road network, land use , soil, and elevation relate to one another. Engineers/ Scientists might use this image to determine areas with more urban growth/