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Maxima, minima and saddle points for functions of two variables
Published in John Bird, Bird's Higher Engineering Mathematics, 2021
The surface z=(x−1)2+(y−2)2 is shown in three dimensions in Fig. 34.7. Looking down towards the x–y plane from above, it is possible to produce a contour map. A contour is a line on a map which gives places having the same vertical height above a datum line (usually the mean sea-level on a geographical map). A contour map for z=(x−1)2+(y−2)2 is shown in Fig. 34.8. The values of z are shown on the map and these give an indication of the rise and fall to a stationary point.
Maxima, minima and saddle points of functions of two variables
Published in John Bird, Mathematics Pocket Book for Engineers and Scientists, 2019
The surface z=(x−1)2+(y−2)2 is shown in three dimensions in Figure 114.1. Looking down towards the x–y plane from above, it is possible to produce a contour map. A contour is a line on a map that gives places having the same vertical height above a datum line (usually the mean sea-level on a geographical map). A contour map for z=(x−1)2+(y−2)2 is shown in Figure 114.2. The values of z are shown on the map and these give an indication of the rise and fall to a stationary point.
Exploratory Data Analysis and Data Visualization
Published in Chong Ho Alex Yu, Data Mining and Exploration, 2022
According to the Environmental Systems Research Institute (ESRI 2021), “a geographic information system (GIS) is a system that creates, manages, analyzes, and maps all types of data. GIS connects data to a map, integrating location data (where things are) with all types of descriptive information (what things are like there). This provides a foundation for mapping and analysis that is used in science and almost every industry. GIS helps users understand patterns, relationships, and geographic context” (para. 1). With GIS, urban planners can understand the needs of a city and then redesign it to fulfill the future needs of its citizens. For example, the Urban Center for Computation and Data at the University
Prisoner and Creator of Space and Place: An Interpretive Descriptive QGIS Study to Understand Exercise Experiences of Community-Dwelling Older Adults in a Low-Income Neighborhood
Published in Journal of Aging and Environment, 2022
Janet L. C. Lee, Yingqi Guo, Temmy L. T. Lo, Rainbow T. H. Ho
Research suggests that physical activity (PA) behavior is a result of a myriad of interrelated individual, social, organizational, environmental and policy factors (Owen et al., 2004; Sallis et al., 1998, 2006). With the belief that changes to the built environment could result in more sustainable changes in PA behaviors, many scholars have used objective measures, such as geographic information systems (GIS), to investigate what aspects of the neighborhood built environment inhibit or promote PA (Hillsdon et al., 2006; Koppen et al., 2014; Weiss et al., 2011). GIS is a digital technology that analyzes and maps spatial data, allowing users to visualize and analyze locations or spatial concentrations of the phenomena of interest (Elwood, 2006). The research findings from these quantitative studies, however, have been inconsistent. For instance, one study found no evidence of a clear relationship between access (i.e., distance, size, and quality) to green space and leisure-related PA (Hillsdon et al., 2006). In contrast, another study found that the amount of green space within a set distance of people’s residences was positively associated with self-reported moderate-to-vigorous PA (Toftager et al., 2011).
Effects of land use and land cover change on soil erosion potential in Berhe district: a case study of Legedadi watershed, Ethiopia
Published in International Journal of River Basin Management, 2022
Mehari Mariye, Melesse Mariyo, Yang Changming, Zebene Lakew Teffera, Brhane Weldegebrial
These topographic maps had been colour-coded for different land covers which include; reservoir, road, Settlement, streams and forest area. The boundary of the watershed was delineated based on these topographic maps of contour lines (represents a ground elevation or vertical distance above a reference point such as sea levels) and contour interval (the difference in elevation between two adjacent contours). Acquired Multi-temporal (1985, 1997 and 2013) satellite imagery of the study area has been imported to ERDAS 9.2 image processing software. Digital Image processing and classification technique have been done using ERDAS Imagine 9.2. The classified images have been used in the extraction of information on the land cover condition and statistical quantification of changes over the last three decades. The satellite images of each band in each year (1985, 1997 and 2013) have been stacked in ERDAS 9.2 within interpreter main icon utilities with layers stacked function. Then, from the stacked satellite images the study area image has been extracted by clipping the area of interest layer of the study shape file from GIS in Arc GIS 10.2 software. We applied different pre-processing techniques such as geometric correction, radiometric corrections, and Lambertian correction to minimize the depiction of vicissitudes due to misregistration and environmental and sensor dissimilarities between the images and to make the multi-date imagery radio metrically consistent. Image of both dates was geo-referenced with respect to each other by collecting high-quality ground control points, and the total RMSE error of geo-referencing was kept below 0.2 pixels.
Implementation of serverless cloud GIS platform for land valuation
Published in International Journal of Digital Earth, 2021
Muhammed Oguzhan Mete, Tahsin Yomralioglu
Real estate valuation is an estimation process of property values with technical knowledge and it depends on many internal and external factors. Evaluating land parcels in large areas like city or district scale requires numerous analysis, data process, and long operation time. In order to carry out this procedure with scientific methods objectively, geographic information systems (GIS) can facilitate to store, view, analyse, and share real estate data and maps.