Integrating Raster Data by Conversion from Raster to Vector Data (Especially for GATE-Geospatial 2022)

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Can take place in data display, data processing, data conversion, or data analysis.

DEM are input data to extract topographic features such as curve, drainage network, watersheds, etc. Most GIS packages allow simultaneous display of raster and vector data.

In Geographical Information System there are three ways to store the data in earth՚s surface: Real world, raster data and vector data

This Figure Shows Three System to Store the Data in Earth՚s …

Need for Both Raster and Vector Data

GISs must integrate both vector and raster data from a variety of sources:

  • Sometimes edges and regions are concluded from a raster image to from a vector model, or conversely, raster images such as aerial photographs are used to update vector models.
  • Several coordinate systems such as Universal Transverse Mercator (UTM) , latitude-longitude, and local cadastral systems are used to identify locations.
  • Data originating from different coordinate systems requires appropriate transformations.

Data Conversion between Vector and Raster

Data conversion must be performed first if the analysis of both raster and vector data is required.

One of the first ArcGIS exercises used an aerial photo (raster data) as the base of a map on which we displayed vector data. Raster and vector integration refers to functions more complex than the ability to simultaneously display both types of data. True integration allows users to employ raster techniques for vector data analysis.

Preference for Vector Information

The main goal is to manipulate vector information instead of raster because their manipulation within GIS engenders many problems. The raster data are not adapted to GIS treatment because of a lack of contextual information, the size of the data and the time-consuming algorithm to produce information.

This Figure Shows Data Source and Data Layers

The raster information is not split into identified objects and the vector representation is more flexible and gives the possibility to be easily combined with other information layers. For these reasons, we aim to split a wide image into several small units and convert the raw image information into a vector of features characterizing the unit in a raster view.

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