Remote Sensing for GIS Managers


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      تحميل كتاب الاستشعار عن بعد لمديري نظم المعلومات الجغرافية Remote Sensing for GIS Managers

      تحميل كتاب الاستشعار عن بعد لمديري نظم المعلومات الجغرافية Remote Sensing for GIS Managers ، استكمالا لسلسلة تعلم نظم المعلومات الجغرافية GIS و الاستشعار عن بعد Remote sensing نقدم لكم في هذه المقالة كتاب الاستشعار عن بعد لمديري نظم المعلومات الجغرافية Remote Sensing for GIS Managers ، من إعداد Stan Aronoff.

      Introduction the book Remote Sensing for GIS Managers

      Digital image analysis

      Digital image analysis is a set of specialized techniques and Computer processing tools used to enhance the visual appearance of and extract information from remotely sensed imagery. İt is also used to rectify imagery to match a selected map base. Though there is some overlap in capabilities, digital image analysis methods have become an important complement to visual interpretation. The most cost-effective means of generating quality information from remotely sensed data commonly makes use of both analysis methods

      Most geographic information systems now provide at least basic image analysis functions to facilitate the use of digital images with other geographic data. Specialized image analysis sofhvare offers a wider range of more sophisticated image analysis operations that can be used to improve the visual interpretability of images as well as generate information for input to a GIS. Whereas basic image enhancement tasks can be easily accomplished by the lay person, more sophisticated analyses are generally undertaken by in-house specialists or outside contractors. This chapter provides an overview of the digital image analysis procedures commonly used in the analysis o f remotely sensed data for GIS applications.
      image analysis functions can be broadly grouped into five categories: image restoration and rectification, image enhancement, calculating indices, classification, and modeling. image restoration and rectification operations correct degraded image data, remove systematic geometric distortions, and change the image geometry to that of a convenient map projection. image enhancement techniques improve visual interpretation by increasing the visual distinction among features for more effective display. indices calclated from the remote sensing image data are used to gener ate measures of image characteristics, such as texture and biophysical measurements, such as sea surface temperatur vegetation condition, and chlorophyll concentration. Classi fication operations automate the identification of features in a scene. The pixels in a digital image are categorized into one of many classes or themes representing different types of fea tures useful to an application, such as land-cover types. This data can then be displayed as a thematic map or tabulated to determine the area of each class. Modeling procedures may incorporate several geospatial datasets derived from remotely sensed imagery and other sources to identify areas with specific characteristics, map current conditions, or predict future developments.

      The data used to calibrate, verify, or support remote sensing analyses is frequently stored within a GIS. The ease with which this data can be applied to remote sensing analyses depends on the data integration capabilities of the sofrvvare, the geometric and classification accuracy of the datasets, and the creativity of the analyst. As with visual interpretation, in digital image analysis the quality and reliability of the resultis in large measure dependent on the Creative implementation of systematic analysis procedures by experienced and well-qualified personnel.