An evaluation of sampling and full enumeration strategies for Fisher Jenks classification in big data settings

Rey, Sergio J.; Stephens, Philip A.; Laura, J.

doi:10.1111/tgis.12236

Cited by 16 publications

(10 citation statements)

References 16 publications

(21 reference statements)

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“…ArcGIS software features a tool for classifying data with the use of the natural breaks classification method. This method is useful for analyzing unevenly distributed data, and it is applied to visualize large datasets in environmental and socioeconomic studies [58][59][60][61][62]. The natural breaks classification method was applied because the analyzed data had an uneven distribution.…”

Section: Evaluation Of the Degree Of Anthropogenic Pressurementioning

confidence: 99%

“…Morskie Oko 9 14 2 Czarny Staw pod Rysami 10 2 0 Total 19 16 2 According to the literature, the impact of anthropogenic pressure on water bodies in the Tatra National Park is not a new research topic and has been studied previously e.g., [11,20,69]. The cited studies analyzed e.g., the composition of lake water and compared their findings with the relevant data from earlier years [11], or investigated the composition of sediment cores to examine the recent environmental history of alpine lakes in the Polish part of the Tatra Mountains [20,61]. The results of the cited analyses indicate, among others, that the content of biogenic elements (mainly nitrogen and phosphorus compounds) in the studied lakes has increased [11,20,70,71].…”

Section: Plant Cover (M 2 )-Covermentioning

confidence: 99%

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The Impact of Recreational Activities on Aquatic Vegetation in Alpine Lakes

Dynowski

Senetra

Źróbek-Sokolnik

et al. 2019

Water

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Tourism pressure on protected areas with attractive landscapes leads to environmental modifications. Eutrophication poses the main threat to the quality of water in alpine lakes. Even small inflows of biogenic elements can disrupt the ecological balance of these ecosystems. The aim of this study was to verify the hypothesis that recreational activities and easy access to alpine lakes contribute to changes in their ecological status. This hypothesis was verified by analyzing the presence of hydromacrophytes in two lakes of the Tatra National Park (Poland). The analysis was carried out along segments of hiking trails which were evaluated for accessibility to the studied lakes. Underwater surveys were carried out during scuba diving expeditions in 2012–2016. Submerged vegetation was evaluated in both lakes. This is the first study in Poland and one of the few projects in the world to have relied on such extensive support from scuba divers to generate highly accurate measurements. The study demonstrated that lake bottoms were extensively covered by Potamogeton friesii in the vicinity of trail segments with easy access to lakes. Our results show that tourism pressure contributes to the growth of aquatic vegetation in some areas of alpine lakes. We relied on our findings to propose several modifications to the routes of the evaluated tourist trails to minimize the impact of anthropogenic pressure on the studied lakes.

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Section: Evaluation Of the Degree Of Anthropogenic Pressurementioning

confidence: 99%

Section: Plant Cover (M 2 )-Covermentioning

confidence: 99%

The Impact of Recreational Activities on Aquatic Vegetation in Alpine Lakes

Dynowski

Senetra

Źróbek-Sokolnik

et al. 2019

Water

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“…The mapclassify package in PySAL addresses the second design imperative. Currently, 15 different classification schemes are available in mapclassify , including a highly optimized implementation of Fisher‐Jenks optimal classification (Rey, Stephens, and Laura 2017). Each scheme inherits a common structure that ensures computations are scalable and supports applications in streaming contexts.…”

Section: Current Analytical Capabilitiesmentioning

confidence: 99%

ThePySALEcosystem: Philosophy and Implementation

Rey

Anselin

Amaral

et al. 2021

Geographical Analysis

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PySAL is a library for geocomputation and spatial data science. Written in Python, the library has a long history of supporting novel scholarship and broadening methodological impacts far afield of academic work. Recently, many new techniques, methods of analyses, and development modes have been implemented, making the library much larger and more encompassing than that previously discussed in the literature. As such, we provide an introduction to the library as it stands now, as well as the scientific and conceptual underpinnings of its core set of components. Finally, we provide a prospective look at the library's future evolution.

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“…Fisher-Jenks algorithm (FJ) [52]; When examining various cases of the distribution of annual minima, one may encounter cases in which the change of the trend is inconclusive or absent (Figure 3) [49]. In this case, Tomaszewski [43] suggests adopting the highest annual minimum flow as the threshold.…”

mentioning

confidence: 99%

Development of an Objective Low Flow Identification Method Using Breakpoint Analysis

Raczyński

Dyer

2022

Water

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Low flow events (a.k.a. streamflow drought) are described as episodes where stream flows are lower or equal to a specified minimum threshold level. This threshold is usually predefined at the methodological stage of a study and is generally applied as a chosen flow percentile, determined from a flow duration curve (FDC). Unfortunately, many available methods for choosing both the percentile and FDCs result in a large range of potential thresholds, which reduces the ability to statistically compare the results from the different methods while also losing the natural character of the phenomenon. The aim of this work is to introduce a new approach for low flow threshold calculation through the application of an objective approach using breakpoint analysis. This method allows for the identification of an environmental moment of river transition, from atmospheric feed flows to base flow, which characterizes the moment at the beginning of the hydrological drought. The method allows for not only the capture of the genesis of a low flow event but, above all, unifies the approach toward threshold levels and completely excludes the impact of the subjective researcher’s decisions, which occur at the methodological stage when selecting the threshold criteria or when choosing a respective percentile. In addition, the method can be successfully used in datasets characterized by a high level of discretization, such as numerical model data, where the subsurface runoff component is not described in sufficient detail. Results of this work show that the objective identification method is better able to capture the occurrence of a low flow event, improving the ability to identify hydrologic drought conditions. The proposed method is published together with the Python module objective_thresholds for broad use in other studies.

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An evaluation of sampling and full enumeration strategies for Fisher Jenks classification in big data settings

Cited by 16 publications

References 16 publications

The Impact of Recreational Activities on Aquatic Vegetation in Alpine Lakes

The Impact of Recreational Activities on Aquatic Vegetation in Alpine Lakes

ThePySALEcosystem: Philosophy and Implementation

Development of an Objective Low Flow Identification Method Using Breakpoint Analysis

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