Application Elements in GIS Photogrammetry

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Geographic Information System (GIS) is consists of hardware and software for collecting, capturing, storing, analyzing and managing data and associated attributes which are spatially referenced to the earth. Geographic Information System (GIS) is capable for integrating, storing, editing, analyzing, sharing and displaying geographic as well as attribute data which are geographically referenced information. It allows the user to create maps, interactive queries, analyze the spatial information, edit data and present the final results of all these operations.

The word Photogrammetry is derived from three Greek words:photos+gramma+metron. It signify measuring graphically by means of light. In other words Photogrammetry means “the science, & art, of determining the size, shape of objects as a consequence of analyzing images recorded on film or electronic media”. With the help of photogrammetry applications we can make Digital Elevation Model(DEM) and Digital Terrain Model (DTM) and other 3D models which will help users for better presentation. Photogrammetry and Geographical Information System (GIS) applications are used for contour development, terrain modeling and for data analysis.

Geographical Information System allows the user to create appropriate maps and photogrammetry allows the user accurately and economically collect mapping data which is essential to the planning, design and construction of infrastructure projects, site development, water and wastewater systems, utilities and GIS programs.

Applications of Photogrammetry: Analysis of oblique and vertical photographs- analysis of vertical and oblique mapping will helps the archaeologists for detail mapping. With the help of photogrammetry and GIS applications we can depict contour lines, digital terrain models and profile of the surface. Digital orthophotos can be created which includes image informations, image enhancement, pattern recognition and other applications, applicable for orthophotos. The data given by the satellites are also falls in the category of image analysis and rectification.

 

Photogrammetry is a remote sensing technique in which geometric properties of the objects are determined from photographic images. In photogrammetry we are taken three dimensional coordinates of points on an object and try to find out the common point on more than two or more images. Photogrammetry techniques allows triangulation method for measuring distance and area. Photogrammetry as a remote sensing technique, collect data of the object or features from remote satellites. Without any direct contact applications can perform. But in GIS or Geographical Information System image processing are performed. We can capture and manipulate data which are stored in the imagery.

Image data are represented as raster and vector data. Raster data is represented as an array of grid system. Each pixel represented some DN value of the image. The values are varying according to the collection of the electromagnetic radiation value. But we can not perform any kind of image processing techniques in raster data format. We have to change image information from raster data to vector data. Vector data represented as point, lines and polygons. After conversion of data we can perform different types of image processing techniques. We can create map with the help of GIS techniques and can built topology, block on the map. All types of photogrammetry processes are performed on the basis of Geographical Information System (GIS) applications.

We can say that Geographical Information System (GIS) and Photogrammetry techniques and applications are interrelated to each other. Application element in GIS photogrammetry can help to create new horizon in the field of GIS and Remote Sensing.