Papers by Robert Gilmore Pontius Jr.
Scientists and policymakers have realised that localities are central to addressing the causes an... more Scientists and policymakers have realised that localities are central to addressing the causes and consequences of global environmental change. The goal of the Human-Environment Regional Observatory project (HERO) was to develop the infrastructure necessary to monitor and understand the local dimensions of global change. This book presents the philosophy behind HERO, the methods used to put that philosophy into action, its results, and the lessons learned from the project. HERO used three strategies: it developed research protocols and data standards for collecting data; it built a web-based networking environment to help investigators share data, analyses and ideas from remote locations; and investigators field-tested these concepts by applying them in diverse biophysical and socioeconomic settings - central Massachusetts, central Pennsylvania, southwestern Kansas, and the US-Mexico border region of Arizona. The book highlights the unique focus of HERO regarding thinking and acting...
Agriculture, Ecosystems & Environment, Jun 1, 2001
The Ipswich watershed in northeastern Massachusetts, USA, is experiencing important land-use chan... more The Ipswich watershed in northeastern Massachusetts, USA, is experiencing important land-use changes, which are contributing to severe environmental problems such as eutrophication, ground water depletion and loss of wildlife. The objective of this paper is to model deforestation between 1971, 1985 and 1991 in the watershed of the Ipswich River in Massachusetts, USA, where most of the forest loss is attributable to new residential development. The maps of suitability for deforestation are calibrated with maps of real change between 1971 and 1985 by using logistic regression, multi-criteria analysis and spatial filters. The maps of 1971 and 1985 serve also as the basis to extrapolate the quantity of predicted future deforestation. Then, the calibrated suitability maps and extrapolated quantities predict the location of deforestation between 1985 and 1991. The predicted deforestation maps are validated with the map of real forest loss of 1985-1991. relative operating characteristic (ROC) and variations of the Kappa index of agreement (Kno, Klocation and Kquantity) measure the validation. For most simulation runs, Kno = 93%, Klocation = 8% and Kquantity = 100%. The best predictor of quantity of deforestation from 1985 to 1991 is linear extrapolation forward in time of the deforestation that occurred from 1971 to 1985. It is difficult to predict the exact locations of deforestation in the watershed because only 2% of the watershed is deforested from 1971 to 1991, the patches of deforestation are scattered evenly across the landscape, and the some of the most important variables are not readily available in digital form. Nevertheless, the best predictor of location of deforestation (ROC = 70%) is a suitability map that uses a spatial filter and multi-criteria evaluation of elevation, slope, and proximity to existing residential areas. The locations that are most threatened are those that are unprotected, near existing residential development and in towns where the demand for new residential development is high.
The Biological Bulletin, Oct 1, 2002
ISPRS Journal of Photogrammetry and Remote Sensing, 2018
Object-based image analysis (OBIA) has gained widespread popularity for creating maps from remote... more Object-based image analysis (OBIA) has gained widespread popularity for creating maps from remotely sensed data. Researchers routinely claim that OBIA procedures outperform pixel-based procedures; however, it is not immediately obvious how to evaluate the degree to which an OBIA map compares to reference information in a manner that accounts for the fact that the OBIA map consists of objects that vary in size and shape. Our study reviews 209 journal articles concerning OBIA published between 2003 and 2017. We focus on the three stages of accuracy assessment: (1) sampling design, (2) response design and (3) accuracy analysis. First, we report the literature's overall characteristics concerning OBIA accuracy assessment. Simple random sampling was the most used method among probability sampling strategies, slightly more than stratified sampling. Office interpreted remotely sensed data was the dominant reference source. The literature reported accuracies ranging from 42% to 96%, with an average of 85%. A third of the articles failed to give sufficient information concerning accuracy methodology such as sampling scheme and sample size. We found few studies that focused specifically on the accuracy of the segmentation. Second, we identify a recent increase of OBIA articles in using per-polygon approaches compared to per-pixel approaches for accuracy assessment. We clarify the impacts of the per-pixel versus the perpolygon approaches respectively on sampling, response design and accuracy analysis. Our review defines the technical and methodological needs in the current per-polygon approaches, such as polygon-based sampling, analysis of mixed polygons, matching of mapped with reference polygons and assessment of segmentation accuracy. Our review summarizes and discusses the current issues in object-based accuracy assessment to provide guidance for improved accuracy assessments for OBIA. Published by Elsevier B.V. on behalf of International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS).
International Journal of Applied Earth Observation and Geoinformation, 2018
This article compares and assesses eight remotely sensed maps of Philippine forest cover in the y... more This article compares and assesses eight remotely sensed maps of Philippine forest cover in the year 2010. We examined eight Forest versus Non-Forest maps reclassified from eight land cover products: the Philippine Land Cover, the Climate Change Initiative (CCI) Land Cover, the Landsat Vegetation Continuous Fields (VCF), the MODIS VCF, the MODIS Land Cover Type product (MCD12Q1), the Global Tree Canopy Cover, the ALOS-PALSAR Forest/Non-Forest Map, and the GlobeLand30. The reference data consisted of 9852 randomly distributed sample points interpreted from Google Earth. We created methods to assess the maps and their combinations. Results show that the percentage of the Philippines covered by forest ranges among the maps from a low of 23% for the Philippine Land Cover to a high of 67% for GlobeLand30. Landsat VCF estimates 36% forest cover, which is closest to the 37% estimate based on the reference data. The eight maps plus the reference data agree unanimously on 30% of the sample points, of which 11% are attributable to forest and 19% to non-forest. The overall disagreement between the reference data and Philippine Land Cover is 21%, which is the least among the eight Forest versus Non-Forest maps. About half of the 9852 points have a nested structure such that the forest in a given dataset is a subset of the forest in the datasets that have more forest than the given dataset. The variation among the maps regarding forest quantity and allocation relates to the combined effects of the various definitions of forest and classification errors. Scientists and policy makers must consider these insights when producing future forest cover maps and when establishing benchmarks for forest cover monitoring.
Journal of Spatial Science, 2016
Abstract Land change in Kigali, Rwanda, is examined using Intensity Analysis, which measures the ... more Abstract Land change in Kigali, Rwanda, is examined using Intensity Analysis, which measures the temporal stationarity of changes among categories. Maps for 1981, 2002 and 2014 were produced that show the land categories Built, Vegetated and Other, which is composed mainly of croplands and bare surfaces. Land change accelerated from the first time interval (1981–2002) to the second time interval (2002–2014), as increased human and economic activities drove land transformation. During the first interval, Vegetated showed net loss whereas Built showed net gain, in spite of a small transition directly from Vegetated to Built. During the second interval, Vegetated showed net gain whereas Built showed nearly equal amounts of gross loss and gross gain. The gain of Built targeted Other during both time intervals. A substantial portion of overall change during both time intervals consisted of simultaneous transitions from Vegetated to Other in some locations and from Other to Vegetated in other locations.
Biological Bulletin, 2003
Sustainable Communities on a Sustainable Planet, 2009
Conservation Biology, 2001
Most quantitative methods for identifying conservation-priority areas require more detailed knowl... more Most quantitative methods for identifying conservation-priority areas require more detailed knowledge about the extent and distribution of biodiversity than is currently available. Accelerated and irreversible losses of biodiversity call for the development of alternative methods to identify priority sites for biodiversity inventory and protection. We focused on the state of Arunachal Pradesh, a biodiversity-rich region in northeast India. We used a geographic information system and spatially explicit modeling to examine the correlation of land-cover and land-use patterns with biogeophysical characteristics and to project future patterns of land-use change. In 1988, 70% of Arunachal Pradesh was covered by forest. We project that 50% of the state's 1988 forest will be lost by 2021, based on anticipated growth of the human population and resulting resource use. Of the total simulated deforestation, 76% occurs in areas that have no legal state protection. We developed a map of threats to biodiversity that divides areas that were forested in 1988 into four categories: (1) susceptible to future deforestation and currently unprotected; (2) susceptible to future deforestation but currently within the protected-area network; (3) not susceptible to future deforestation and protected; and (4) neither susceptible to future deforestation nor currently protected. We make the following recommendations based on our analyses. Areas in category 1 should be a high priority for biodiversity inventory and conservation action. Areas in category 2 should have rigid enforcement of protection. Areas in category 3 are locations of relatively low priority for enforcement. Areas in category 4 that have a high conservation potential are politically the easiest to include in the protected-area network and should be protected before they become targets of future land-use change. Reserve forests-forests managed by the state forest department for a variety of purposes, including selective logging for timber harvesting-are predominantly located in areas susceptible to land-use change and are prime candidates for upgrading of protection status. Identificación de Areas Prioritarias de Conservación en los Trópicos: un Modelo Enfocado al Cambio en el Uso del Suelo Resumen: La mayoría de los métodos cuantitativos para identificar áreas prioritarias de conservación requieren de conocimiento más detallado que el que actualmente se tiene acerca de la magnitud y distribución de la biodiversidad. La pérdida acelerada e irreversible de biodiversidad exige el desarrollo de métodos alternativos para identificar sitios prioritarios para inventariar y proteger la biodiversidad. Enfocamos el estado de Arunachal Pradesh, una región rica en biodiversidad del noreste de India. Utilizamos SIG y modelos espacialmente explícitos para examinar la correlación de superficie y patrones de uso del suelo con características biogeofísicas y para proyectar patrones futuros de cambio en el uso del suelo. En 1988, el 70% de Arunachal Pradesh estaba cubierto por bosques. Proyectamos que 50% de los bosques de 1988 se perderá para 2021 con base en el crecimiento esperado de la población humana y la resultante utilización de recursos. Del total de deforestación simulada, 76% ocurre en áreas que no tienen ninguna protección legal. Elaboramos un mapa de amenazas a la biodiversidad que divide en cuatro categorías a las áreas boscosas en
Photogrammetric Engineering and Remote Sensing, 2000
... hyperspectral sensing, the large number of new governmental and commercial satellite systems,... more ... hyperspectral sensing, the large number of new governmental and commercial satellite systems, digital ... GIS fields, with a particular emphasis on mathematical techniques and their application. ... The range of applications includes land-cover and land-use mapping, cloud tracking ...
The Biological Bulletin, Oct 1, 2004
This paper proposes a method to improve landscape-pollution interaction regression models through... more This paper proposes a method to improve landscape-pollution interaction regression models through the inclusion of a variable that describes the spatial distribution of a land type with respect to the pattern of runoff within a drainage catchment. The proposed index is used as an independent variable to enhance the strength, as quantified by R² values, of regression relationships between empirical observations of in-stream pollutant concentrations and land type by considering the spatial distribution of key land-type categories within the sample point's drainage area. We present an index that adds a new dimension of explanatory power when used in conjunction with a variable describing the proportion of the land type. We demonstrate the usefulness of this index by exploring the relationship between nitrate (− 3 NO) and land type within 40 drainage sub-catchments in the Ipswich River watershed, Massachusetts. Nutrient loads associated with non-point source pollution paths are related to land type within the upstream drainage catchments of sample sites. Past studies have focused on the quantity of particular land type within a sample point's drainage catchment. Quantifying the spatial distribution of key land-type categories in terms of location on a runoff surface can improve our understanding of the relationship between sampled − 3 NO concentrations and land type. Regressions that employ the proportion of residential and agricultural land type within catchments provide a fair fit (R² = 0.67). However, we find that a regression adding a variable that indicates the spatial distribution of residential land improves the overall relationship between instream − 3 NO measurements and associated land types (R² = 0.712). We test the sensitivity of the results with respect to variations in the surface definition in order to determine the conditions under which the spatial index variable is useful.
Land
The Flow matrix is a novel method to describe and extrapolate transitions among categories. The F... more The Flow matrix is a novel method to describe and extrapolate transitions among categories. The Flow matrix extrapolates a constant transition size per unit of time on a time continuum with a maximum of one incident per observation during the extrapolation. The Flow matrix extrapolates linearly until the persistence of a category shrinks to zero. The Flow matrix has concepts and mathematics that are more straightforward than the Markov matrix. However, many scientists apply the Markov matrix by default because popular software packages offer no alternative to the Markov matrix, despite the conceptual and mathematical challenges that the Markov matrix poses. The Markov matrix extrapolates a constant transition proportion per time interval during whole-number multiples of the duration of the calibration time interval. The Markov extrapolation allows at most one incident per observation during each time interval but allows repeated incidents per observation through sequential time inte...
This paper gives a technique to extrapolate the anticipated accuracy of a prediction of land-use ... more This paper gives a technique to extrapolate the anticipated accuracy of a prediction of land-use and land-cover change (LUCC) to any point in the future. The method calibrates a LUCC model with information from the past in order to simulate a map of the present, so that it can compute an objective measure of validation with empirical data. Then it uses that observed measurement of predictive accuracy to anticipate how accurately the model will predict a future landscape. The technique assumes that the accuracy of the model will decay to randomness as the model predicts farther into the future and estimates how fast the decay in accuracy will occur based on prior model performance. Results are presented graphically in terms of percentage of pixels classified correctly so that nonexperts can interpret the accuracy visually. The percentage correct is budgeted by three components: agreement due to chance, agreement due to the predicted quantity of each land category, and agreement due t...
Advances in geographic information science, 2022
The use of general descriptive names, registered names, trademarks, service marks, etc. in this p... more The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.
Neste trabalho procura-se rastrear as concepções pedagógicas do poeta Augusto dos Anjos através d... more Neste trabalho procura-se rastrear as concepções pedagógicas do poeta Augusto dos Anjos através do exame de sua prosa, de sua correspondência e das memórias de seus colegas e alunos. Formado na Faculdade de Direito do Recife, casado com a normalista Esther Fialho, que viria a seguir a carreira de professora após sua morte, professor do Liceu Paraibano, do Ginásio Nacional e da Escola Normal do Rio de Janeiro, o poeta exprime de diversas maneiras a pedagogia em voga no Brasil no início do século XX. Da análise, emerge uma filosofia da educação, própria do ensino bacharelesco daquele período histórico, onde o verbalismo assoma como característica mais pronunciada. A teoria do conhecimento subjacente a essa filosofia da educação manifesta-se claramente na semântica de seus poemas, recheada de vocábulos retirados da literatura científica. No entanto, tal como em sua poesia, as tensões provocadas pelo anseio de modernização da sociedade naquela fase de nossa história, também se fizeram presentes em suas concepções educacionais. This work tries to trace out the pedagogic conceptions of the celebrated poet Augusto dos Anjos through the analysis of his prose, correspondence and written memories of bis friends and pupils. Graduated by the Faculdade de Direito do Recife, married with Esther Fialho, a student of teaching school that became a successful teacher after bis death, lecturing at the Liceu Paraibano, Ginásio Nacional and Escola Normal do Rio de Janeiro, the poet expressed in many ways the prevailing pedagogy in the beginnings of Brazil's twentieth century. From the analysis arises a pbilosophy of education in conformity with the bookish teaching wbich was in vogue at that historical period of Brazilian education, where the verbalism was the most striking characteristic. The epistemology under1ying this philosophy of education is clearly displayed in the semantics of bis poetry, generally filled with scientific words. However, like happens with bis poems, the tenseness of the modernity of his age also was present in his educational practice.
This paper explores the use of spatial interpolative methods in conjunction with object based ima... more This paper explores the use of spatial interpolative methods in conjunction with object based image analysis to estimate turf grass land cover quantity and allocation in Greater Boston, Massachusetts, USA. The goal is to learn how accurately turf grass can be estimated if only a limited portion of the study area is mapped. First, turf grass land cover is mapped at the 0.5 m resolution across the entire Plum Island Ecosystems (PIE) Long Term Ecological Research (LTER) site, a 1143-km 2 area. Second, the turf grass map is aggregated into 120 m cells (N = 84,661). Third, a random sample of these 120 m cells are selected to generate an estimate of the unselected cells using four estimation methods-Inverse Distance Weighting, Kriging, Polygonal Interpolation, and Mean Estimation. The difference between known and estimated values is recorded using 120 m cell and census block group stratifications. This process is repeated 500 times for sample sizes of 2.5%, 5.0%, 7.5% and 10.0% of the stu...
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Papers by Robert Gilmore Pontius Jr.