Systems for data processing, anaylsis and representation

Allam, Mosaad; Plunkett, Gordon

Bibliographic data

Monograph

Persistent identifier:: 1067490280

Title:: Systems for data processing, anaylsis and representation

Sub title:: ISPRS Commission II Symposium : June 6 - 10, Ottawa, Canada

Scope:: 1 Online-Ressource (XX, 530 Seiten)

Year of publication:: 1994

Place of publication:: Ottawa

Publisher of the original:: The Surveys, Mapping and Remote Sensing, Natural Resources Canada

Identifier (digital):: 1067490280

Illustration:: Illustrationen

Signature of the source:: ZS 312(30,2)

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist aus dem Copyrightjahr ermittelt.

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

Editor:: Allam, Mosaad; Plunkett, Gordon

Corporations:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Adapter:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Founder of work:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Other corporate:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2019

Document type:: Monograph

Collection:: Earth sciences

Chapter

Title:: [Wednesday, June 8, 1994]

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: [Joint ISPRS/ GIS '94 Plenary III]

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: THE USE OF GPS FOR GIS GEOREFERENCING: STATUS AND APPLICATIONS M. Elizabeth Cannon

Document type:: Monograph

Structure type:: Chapter

to multipath compared to a 6 channel receiver. Also, differences in the receiver tracking loop design may also affect the performance of a particular receiver in a sub-optimal environment since this may affect both multipath susceptibility and satellite re-acquisition times. Several tests have been conducted to assess the performance of GPS in urban environments, and one such test is reported in Melgard et al. (1994). In this case, three receivers were assessed, i.e. two six channel receivers and one ten channel receiver, in both a residential and urban environment. The three receivers were mounted in a truck which drove a trajectory consisting of both residential and urban areas. Three test runs were conducted, each lasting about 1.5 hours. The results were analysed according the availability of GPS, which is defined as the percentage of time that at least four satellites were observed. Table 4 gives the statistics for each of the three receiver types. The table clearly shows that the performance from each receiver is not equal, and that the 10 channel receiver has better availability statistics than the six channel receivers, as expected. The statistics for the entire trajectory are about 9096 for the 10 channel receiver while it is about 50-7096 for the six channel receivers. Table 4 also shows that the performance is significantly better in a residential area as compared to the downtown area. The availability drops to 50-70% from 92-100 % for the ten channel receiver and 16-43% for the six channel receivers from 23-91%. These tests confirm that receiver selection is critical for cases when sub-optimal conditions will be observed. Table 4: GPS Availability Statistics (%) Test# Trajectory Receiver 1 2 3 Downtown 51 16 40 1 Residential 98 91 78 Entire Traj. 88 67 73 Downtown 69 39 43 2 Residential 100 68 61 Entire Traj. 92 66 75 Downtown 57 31 35 3 Residential 92 24 23 Entire Traj. 88 51 60 4.3 Precision Farming The application of GPS to the agricultural industry is beginning to accelerate due to the 168 reduction in receiver costs. The University of Calgary, together with Alberta Agriculture, is currently developing a system which can be used to measure the variability of crop production as a function of location (Gehue et al., 1994). The system consists of several components which include GPS receivers for positioning, a yield monitoring system which outputs the instantaneous Bu per acre, an EM conductivity meter for salinity measurements, and soil samples for determination of soil types and nutrients. The DGPS/yield monitoring data can be collected under normal combining operations. Two 10-channel C/A code narrow correlator spacing NovAtel GPSCard™ sensors were used as they have shown to provide sub-metre accuracy in previous field tests using a robust carrier phase smoothing of the code approach (e.g. Cannon and Lachapelle, 1992). Once all this data has been collected and analysed, variable fertilizing can be used in subsequent years to optimize productivity. DGPS can be used as a real-time navigation and guidance tool for this application. A GIS is used to organize and collate the variety of data collected from year to year. Various layers of information can be draped (using surfacing routines) over each other through the DGPS position. It is then possible to overlay crop yields with salinity, for example, and draw conclusions based on the relationship (i.e., high salinity results in low yield). Further, predictions can be made on how to handle these regions when it is time to fertilize and/or seed. The GIS can also be updated with external information such as aerial photography or remote sensing. Current information layers of topography, salinity, soil type, nutrients, and crop yields were collected for the 1993 harvest. The goal of the precision farming project is to optimize the yield-input relationship for any given field. Since this is the first harvest season of the project, results to date only give an indication of the variation within the field for this year, with the condition that it has been treated equally in the past. A surfacing routine is used to view the yield variations with the result shown in Figure 5 for a subset of the test site. The figure clearly shows that the field is not homogeneous in yield. Surface analysis of crop yields allows agricultural researchers to identify problem areas and to maintain data quality by detecting results such as the sudden peak in the NE corner of the field which is most likely caused by high moisture in the swath which returns a false reading from the yield sensor. Fig. 5 Once all : their res| between informati potential specific s have sev have di fertilizers yield. Th take into topograp applicati. The test f steep noi monitor : the movii km from harvestec Novembe locations Table 5: Smoothir Dat | Sept. 2 Nov. 9 The posi: project are Two techr namely a and a on- (OTF). T verified using the: Was used

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