Remote sensing for resources development and environmental management: Remote sensing for resources development and environmental management

damen, m. c. j.

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Multivolume work

Persistent identifier:: 856342815

Title:: Remote sensing for resources development and environmental management

Sub title:: proceedings of the 7th international Symposium, Enschede, 25 - 29 August 1986

Year of publication:: 1986

Place of publication:: Rotterdam; Boston

Publisher of the original:: A. A. Balkema

Identifier (digital):: 856342815

Language:: English

Additional Notes:: Volume 1-3 erschienen von 1986-1988

Editor:: Damen, M. C. J.

Document type:: Multivolume work

Volume

Persistent identifier:: 856641294

Title:: Remote sensing for resources development and environmental management

Sub title:: proceedings of the 7th international Symposium, Enschede, 25 - 29 August 1986

Scope:: IX Seiten, Seiten 551-956

Year of publication:: 1986

Place of publication:: Rotterdam; Boston

Publisher of the original:: A,. A. Balkema

Identifier (digital):: 856641294

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(26,7,2)

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: Damen, M. C. J.

Editor:: International Society for Photogrammetry and Remote Sensing, Commission of Photographic and Remote Sensing Data

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: 7 Human settlements: Urban surveys, human settlement analysis and archaeology. Chairman: W. G. Collins, Co-chairman: B. C. Forster, Liaison: P. Hofstee

Write comment:: Wegen zu enger Bindung kommt es teilweise im Original zu Textverlust.

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: Urban-land-cover-type adequate generalization of thermal scanner images. Peter Mandl

Document type:: Multivolume work

Structure type:: Chapter

847 Symposium on Remote Sensing for Resources Development and Environmental Management / Enschede / August 1986 Urban-land-cover-type adequate generalization of thermal scanner images Peter Mandl Institute of Geography, University Klagenfurt, Austria ABSTRACT: A thermal infrared image showing the urban area of Klagenfurt, Austria on a cloudless day in autumn 1979 is generalized by forming radiometric and spatial classes and by clustering temperature-value-histograms of these generalized data. The results are plotted in map resembling form and interpreted according to thermal urban-land-cover-types. The errors appearing in such a generalization are analysed in detail. Some of these com plex land cover classes are investigated in detail trying to explain their temperature distributions by the per centages of overbuilt and vegetated areas within these different urban'housing quarters. The results of this study can be used for urban climate investigations and town planning purposes. 1 INTRODUCTION There are three points which characterize modern aeri al remote sensing and which distinguish it from clas sical aerial photo interpretation. The first point is the possibility to acquire images in the non-visible parts of the electromagnetic spectrum like the micro- wave or the thermal infrared region. The second point is the sensing of discrete and calibrated measurements (e.g. by scanner) which allows the drawing of measure ment maps and is also the base for the third point, the utilization of digital computers to use methods of pattern recognition, statistics, etc. for handling and analysing the huge amounts of data. These features of modern remote sensing have extended the applications of this technology in the last two decades. One field of research which got many impulses by utilizing these new features of remote sensing (parti cularly by the introduction of computerenhanced and analysed thermal infrared images) is micro climatolo gy, especially urban climatology and the application of the findings there in town and regional planning. A very good review on urban climate research is D.O.Lee (1984). One main problem of these sciences is to get measurements of climatic parameters covering the terrain more or less continuously. The classical method to solve this probletn is to drive measurement traverses over the test area or to have a fix sensor network and to interpolate the data between the mea sured traverses or points (e.g. Oke & Hannell 1970 or Niibler 1979) . Now remote sensing can provide urban climatology with continuous terrain covering measurements on radia tion temperature. Unfortunately this parameter is of no direct use for climatology and a conversion of radiation temperatures to surface temperatures is com plicated because of the differnt error sources that influence the remotely sensed data. Nevertheless spe cial processed, enhanced and printed images of the thermal infrared emission of urban areas have been used to find out "heat islands" in various towns, fresh air areas in the surrounding of towns or fresh air canals into the central towns and to give basic informations for planning purposes. The aims of this study now are to show special as pects of the heat emission field of the urban area of Klagenfurt, Austria on a cloudless day at 10 o'clock in the morning in autumn. The primary data for this were thermal infrared ^mages (8 - 13 ^m wavelength) acgiired by a Bendix M S 11-channel scanner on the 13 of September 1979. A correction of the radiomet ric errors in the image which are intern relative er rors (0,1-0,2 C), errors due to the atmosphere bet ween the objects and the sensor (minus 1-3,5 C for the correction from radiation to surface temperature), errors due to the emission coefficients of different surface cover types and influences of the different viewing angles in the image on the thermal emission distribution of various areas seemed not necessary for the purposes of this study. In a first part of this study images of the primary data, geometrically rectified from the panoramic dis tortion, sliced into five temperature classes were pro duced (Fig. 1). The pixels then were stepwise combined to "macropixels" consisting of 10x10, 25x25, 50x50 and 100x100 "micropixels" by calculating the arith metic mean value of every macrdpixel. An example of the resulting images is given in Fig. 2. All the re sults of this first part of the study are described in detail in Seger & Mandl 1985. In the second part of this study which will be des cribed in this paper three main problems are dealt with: 1. The determination of the temperature distributi ons of typical urban-land-cover-types and their rela tions to the proportions of vegetation, asphalt and houses in test areas, to find out if thermal data can be a good indicator for such "pure" land cover types. 2. An error investigation of different generaliza tions of the radiometric and the spatial domain of the thermal image data. 3. The attempt of a régionalisation of the thermal image using temperature-value-histograms of the macro pixels as variables and cluster analysis as classifi cation method. 2 SOME ASPECTS OF THE GENERALIZATION PROBLEM OF REMOTE SENSING DATA Digital remote sensing data can be characterized by four different types of resolution. In this study the temporal and the spectral resolution of the data is held constant, a thermal infrared image (9 - 13 /im) at one acquisition date is used. The spatial resolu tion of the primary data is 2,3m x 2,3m at the nadir point and the radiometric resolution is 0,12 C tem perature intervall from one data value to the other. The thermal image of Klagenfurt consists of 803 x 3.200 pixels. Each pixel has a precision of 256 pos sible values which means that the amount of informa tion in the image is greater than 20,5 million bits. In order to seperate the user important information (signal) from the unimportant one (noise) a very well- considered and well-balanced correspondence between the objectiv,the degree or level of generalization and the methods used for this have to be found. There are

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