Robert Gilmore Pontius Jr, PhD

Professor

Clark University

School of Geography

Advisor to Master of Science in Geographic Information Science for Development and Environment (GISDE)

950 Main Street

Worcester MA 01610-1477

USA

OFFICE PHONE 001 508 793 7761

OFFICE FAX 001 508 793 8881

EMAIL rpontius@clarku.edu

Updated 8 June 2018.

Welcome to Gil Pontius’ home page from which you can obtain copies of the publications below. If you would like my other publications, please see my CV, and then send your request to me (rpontius@clarku.edu).

CLICK HERE FOR VIDEOS.

Read the National Research Council’s 2013 book “Advancing Land Change Modeling: Opportunities and Research Requirements” by clicking the here.

See my Doctor Stardust juggling video by clicking the here.

PUBLICATIONS AS JOURNAL ARTICLES:

1. R G Pontius Jr. in review. Component Intensities to relate difference by category with difference overall. Click on the title to download the data.
2. R Estoque, R G Pontius Jr, Y Murayama, H Hou, R B Thapa, R D Lasco, M A Villar. 2018. Simultaneous Comparison and Assessment of Eight Remotely Sensed Maps of Philippine Forests. International Journal of Applied Earth Observation and Geoinformation 67: 123-134. DOI: 10.1016/j.jag.2017.10.008. Left click to request a copy.
3. B Huang, J Huang, R G Pontius Jr, Z Tu. 2018. Comparison of Intensity Analysis and the land use dynamic degrees to measure land changes outside versus inside the coastal zone of Longhai, China. Ecological Indicators 89: 336-347. DOI: 10.1016/j.ecolind.2017.12.057. Left click to request a copy.
4. B Quan, R Hongge, R G Pontius Jr, P Liu. 2018. Quantifying Spatiotemporal Patterns Concerning Land Change in Changsha, China. Landscape and Ecological Engineering. Left click to request a copy.
5. F O Akinyemi, Braimoh, R G Pontius Jr, A K Braimoh. 2017. Land change dynamics: insights from Intensity Analysis applied to an African emerging city. Spatial Science 62(1): 69-83. DOI: 10.1080/14498596.2016.1196624. Left click to request a copy.
6. R G Pontius Jr, J Huang, W Jiang, S Khallaghi, Y Lin, J Liu, B Quan, S Ye. 2017. Rules to write mathematics to clarify metrics such as the land use dynamic degrees. Landscape Ecology 32(12): 2249-2260. DOI: 10.1007/s10980-017-0584-x.
7. R G Pontius Jr, R Krithivasan, L Sauls, Y Yan, Y Zhang. 2017. Methods to summarize change among land categories across time intervals. Journal of Land Use Science 12(4): 218-230. DOI: 10.1080/1747423X.2017.1338768. Left click to request a copy. You can download a free computer program to compute States when maps are in TerrSet by clicking here. You can download a free computer program to compute Incidents when maps are in TerrSet by clicking here.
8. A V Bradley, I M D Rosa, R G Pontius Jr, S E Ahmed, M B Araujo, D G Brown, A Brandão Jr, G Câmara, T G S Carnerio, A J Hartley, M J Smith, R M Ewers. 2016. SimiVal, a multi-criteria map comparison tool for land-change model projections. Environmental Modelling & Software 82: 229-240. Left click to request a copy.
9. Z Teixeira, J C Marques, R G Pontius Jr. 2016. Evidence for deviations from uniform changes in a Portuguese watershed illustrated by CORINE maps: An Intensity Analysis approach. Ecological Indicators 66: 382-390. Left click to request a copy.
10. P Zhou, J Huang, R G Pontius Jr, and H Hong. 2016. New insight into the correlations between land use and water quality in a coastal watershed of China: Does point source pollution weaken it? Science of the Total Environment 543: 591-600. Left click to request a copy.
11. S Aldwaik, J Onsted and RG Pontius Jr. 2015. Behavior-based aggregation of land categories for temporal change analysis. International Journal of Applied Earth Observation and Geoinformation 35: 229-238. Left click to request a copy. You can download a free computer program to perform the analysis by clicking here.
12. S Blanchard, R G Pontius Jr, and K M Urban. 2015. Implications of using 2m versus 30 m spatial resolution data for suburban residential land change modeling. Journal of Environmental Informatics 25(1): 1-13. Left click to request a copy.
13. M T Camacho Olmedo, R G Pontius Jr, M Paegelow and J-F Mas. 2015. Comparison of simulation models in terms of quantity and allocation of land change. Environmental Modelling & Software 69: 214-221. Left click to request a copy.
14. G Enaruvbe and R G Pontius Jr. 2015. Influence of classification errors on Intensity Analysis of land changes in southern Nigeria. International Journal of Remote Sensing 31(1): 244-261. Left click to request a copy.
15. J Huang, Y Huang, R G Pontius Jr, and L Huang. 2015. Geographically Weighted Regression to measure spatial variations in correlations between water pollution versus land use in a watershed. Ocean & Coastal Management 103: 13-24. Left click to request a copy.
16. RG Pontius Jr and A Santacruz. 2014. Quantity, Exchange, and Shift Components of Difference in a Square Contingency Table. International Journal of Remote Sensing 35(21): 7543-7554. Left click to request a copy. You can also download the Excel file to perform the calculations with your own data by clicking here. See the video in English or Spanish by clicking here.
17. RG Pontius Jr and B Parmentier. 2014. Recommendations for using the Relative Operating Characteristic (ROC). Landscape Ecology 29(3): 367-382. Left click to request a copy. You can also download the supplement to the manuscript by clicking here.
18. RG Pontius Jr and K Si. 2014. The total operating characteristic to measure diagnostic ability for multiple thresholds. International Journal of Geographical Information Science 28(3): 570-583. Left click to request a copy. You can also download the data that the manuscript uses by clicking here. Create your TOC curve with a spreadsheet by clicking here, or use R code available for free. See videos concerning the TOC by clicking here. Get an Excel file that shows generalized examples of TOC curves by clicking here.
19. N M Giner, C Polsky, RG Pontius Jr, DM Runfola and SJ Ratick. 2014. Creating Spatially-Explicit Lawn Maps Without Classifying Remotely-Sensed Imagery: The case of suburban Massachusetts, USA. Cities and the Environment 7(1) article 10: 28 pages. Left click to request a copy.
20. Y Liu, Y Feng and RG Pontius Jr. 2014. Spatially-Explicit Simulation of Urban Growth through Self-Adaptive Genetic Algorithm and Cellular Automata Modelling. Land 3(3): 719-738. Left click to obtain the manuscript from the journal’s open access web site.
21. DSM Runfola, T Hamill, RG Pontius Jr, J Rogan, N Giner, and A Decatur and S Ratick. 2014. Using Fine Resolution Orthoimagery and Spatial Interpolation to Rapidly Map Turf Grass in Suburban Massachusetts. International Journal of Geospatial and Environmental Research 1(1): article 4, 17 pages. Left click to request a copy.
22. G Villamor, R G Pontius Jr, and M van Noordwijk. 2014. Agroforest’s growing role in reducing carbon losses from Jambi (Sumatra), Indonesia. Regional Environmental Change. 14(2): 825-834. Left click to request a copy.
23. P Zhou, J Huang, R G Pontius Jr, H Hong. 2014. Land Classification and Change Intensity Analysis in a Coastal Watershed of Southeast China. Sensors 14(7): 11640-11658. Left click to obtain the manuscript from the journal’s open access web site.
24. S Aldwaik and RG Pontius Jr. 2013. Map errors that could account for deviations from a uniform intensity of land change. International Journal of Geographical Information Science 27(9): 1717-1739. Left click to request a copy. You can download a free 8MB computer program to perform the analysis by right clicking here.
25. D G Brown, Peter H Verburg, R G Pontius Jr and Mark D Lange. 2013. Opportunities to improve impact, integration, and evaluation of land change models. Current Opinion in Environmental Sustainability 5: 452-457. Left click to request a copy.
26. N M Giner, C Polsky, R G Pontius Jr, and D M Runfola. 2013. Understanding the social determinants of lawn landscapes: A fine-resolution spatial statistical analysis in suburban Boston, Massachusetts, USA. Landscape and Urban Planning 111: 25-33. Left click to request a copy.
27. J Huang, Q Li, R G Pontius Jr, V K, and H Hong. 2013. Detecting the dynamic linkage between landscape characteristics and water quality in a subtropical coastal watershed, southeast China. Environmental Management 51(1): 32-44. Left click to request a copy.
28. J-F Mas, B Soares Filho, R G Pontius Jr, M Farfan Gutierrez and H Rodrigues. 2013. A suite of tools for ROC analysis of spatial models. ISPRS International Journal of Geo-Information 2(3): 869-887. Left click to obtain the manuscript from the journal’s open access web site.
29. M Paegelow, M T Camacho Olmedo, T. Houet, J-F Mas and RG Pontius Jr. 2013. Land Change Modelling: Moving Beyond Projections. International Journal of Geographical Information Science 27(9): 1691-1695. Left click to request a copy.
30. R G Pontius Jr, Y Gao, NM Giner, T Kohyama, M Osaki and K Hirose. 2013. Design and interpretation of Intensity Analysis illustrated by land change in Central Kalimantan, Indonesia. Land 2(3): 351-369. Left click to obtain the manuscript from the journal’s open access web site.
31. D M Runfola, C Polsky, C Nicolson, N Giner, RG Pontius Jr, J Krahe, A Decatur. 2013. A Growing Concern? Examining the Influence of Lawn Size on Residential Water Use in Suburban Boston, MA, USA. Landscape and Urban Planning 119: 113-123. Left click to request a copy.
32. D M Runfola and RG Pontius Jr. 2013. Measuring the Temporal Instability of Land Change using the Flow Matrix. International Journal of Geographical Information Science 27(9): 1696-1716. Left click to request a copy.
33. S Aldwaik and R Pontius Jr. 2012. Intensity Analysis to unify measurements of size and stationarity of land changes by interval, category, and transition. Landscape and Urban Planning 106: 103-114. Left click to request a copy. You can download a free 8MB computer program to perform the analysis by right clicking here.
34. V Gutierrez-Velez and R G Pontius Jr. 2012. Influence of carbon mapping and land change modelling on the prediction of carbon emissions from deforestation. Environmental Conservation 39(4): 325-336. Left click to request a copy.
35. J Huang, R G Pontius Jr, Q Li, and Y Zhang. 2012. Use of Intensity Analysis to Link Patterns with Processes of Land Change from 1987 to 2007 in a Coastal Watershed of Southeast China. Applied Geography 34: 371-384. Left click to request a copy.
36. H Chen and R G Pontius Jr. 2011. Sensitivity of a land change model to pixel resolution and precision of the independent variable. Environmental Modeling & Assessment 16: 37-52. Left click to request a copy.
37. Y Gao, P Marpu, I Niemeyer, D M Runfola, N M Giner, T Hamill, and R G Pontius Jr. 2011. Object-based classification with features extracted by a semi-automatic feature extraction algorithm - SEaTH. Geocarto International 26(3): 211-226. Left click to request a copy. Table 4 has an error in the total column but the corresponding figure 5 is correct.
38. R G Pontius Jr, S Peethambaram and J-C Castella. 2011. Comparison of three maps at multiple resolutions: a case study of land change simulation in Cho Don District, Vietnam. Annals of the Association of American Geographers 101(1): 45-62. Left click to request a copy.
39. R G Pontius Jr and M Millones. 2011. Death to Kappa: birth of quantity disagreement and allocation disagreement for accuracy assessment. International Journal of Remote Sensing 32(15): 4407-4429. Left click to request a copy. Download an Excel file to perform the calculations by clicking the link highlighted in green below.
40. H Chen and R G Pontius Jr. 2010. Diagnostic tools to evaluate a spatial land change projection along a gradient of an explanatory variable. Landscape Ecology 25: 1319-1331. Left click to request a copy.
41. R Manandhar, Inakwu O A Odeh and R G Pontius Jr. 2010. Analysis of twenty years of categorical land transitions in the Lower Hunter of New South Wales, Australia. Agriculture Ecosystems and Environment, 135: 336-346. Left click to request a copy.
42. R G Pontius Jr and X Li. 2010. Land transition estimates from erroneous maps. Journal of Land Use Science 5(1): 31-44. Left click to request a copy.
43. R G Pontius Jr and N Neeti. 2010. Uncertainty in the difference between maps of future land change scenarios. Sustainability Science. Left click to request a copy. Click here to see the video!
44. R G Pontius Jr and S Petrova. 2010. Assessing a predictive model of land change using uncertain data. Environmental Modeling & Software 25(3): 299-309. Left click to request a copy.
45. R G Pontius Jr and J Connors. 2009. Range of categorical associations for comparison of maps with mixed pixels. Photogrammetric Engineering & Remote Sensing, 75(8): 963-969. Left click to request a copy.
46. R G Pontius Jr, W Boersma, J-C Castella, K Clarke, T de Nijs, C Dietzel, Z Duan, E Fotsing, N Goldstein, K Kok, E Koomen, C D Lippitt, W McConnell, A Mohd Sood, B Pijanowski, S Pithadia, S Sweeney, T N Trung, A T Veldkamp, and P H Verburg. 2008. Comparing input, output, and validation maps for several models of land change. Annals of Regional Science, 42(1): 11-47. Left click to request a copy. The same document is available at http://www.springerlink.com. Click here to download a 5MB copy of the data.
47. R G Pontius Jr, O Thontteh and H Chen. 2008. Components of information for multiple resolution comparison between maps that share a real variable. Environmental and Ecological Statistics, 15(2): 111-142. Left click to request a copy. The same document is available at http://www.springerlink.com.
48. C Alo and R G Pontius Jr. 2008. Identifying systematic land cover transitions using remote sensing and GIS: The fate of forests inside and outside protected areas of Southwestern Ghana. Environment and Planning B, 35(2): 280-295. Left click to request a copy.
49. K Kuzera and R G Pontius Jr. 2008. Importance of matrix construction for multiple-resolution categorical map comparison. GIS and Remote Sensing, 45(3): 249-274. Left click to request a copy. Equation 11 has an error; the numerator of equation 11 should be [Prgij – (Prgi+ × Prg+j)]^2.
50. R G Pontius Jr, R Walker, R Yao-Kumah, E Arima, S Aldrich, M Caldas and D Vergara. 2007. Accuracy assessment for a simulation model of Amazonian deforestation. Annals of Association of American Geographers, 97(4): 677-695. Left click to request a copy. The same document is available at http://www.blackwell-synergy.com.
51. R G Pontius Jr, A J Versluis and N R Malizia. 2006. Visualizing certainty of extrapolations from models of land change. Landscape Ecology 21(7) p.1151-1166. Left click to request a copy.
52. R G Pontius Jr and C D Lippitt. 2006. Can error explain map differences over time? Cartography and Geographic Information Science 33(2) p.159-171. Right click to download.
53. R G Pontius Jr and M L Cheuk. 2006. A generalized cross-tabulation matrix to compare soft-classified maps at multiple resolutions. International Journal of Geographical Information Science 20(1) p.1-30. Left click to request a copy.
54. E Fedorko, R G Pontius Jr, S Aldrich, L Claessens, C Hopkinson Jr, and W Wolheim. 2005. Spatial distribution of land type in regression models of pollutant loading. Journal of Spatial Hydrology 5(2) p.60-80. Right click to download.
55. R G Pontius Jr and J Malanson. 2005. Comparison of the structure and accuracy of two land change models. International Journal of Geographical Information Science 19(2) p.243-265. Left click to request a copy.
56. R G Pontius Jr and J Spencer. 2005. Uncertainty in extrapolations of predictive land change models. Environment and Planning B 32 p.211-230. Right click to download. This paper won the Michael Breheny Prize for the Best Paper in Environment and Planning B in 2005.
57. R G Pontius Jr, D Huffaker and K Denman. 2004. Useful techniques of validation for spatially explicit land-change models. Ecological Modelling 179(4) p.445-461. Left click to request a copy.
58. R G Pontius Jr and N R Malizia. 2004. Effect of category aggregation on map comparison. Lecture Notes in Computer Science 3234 p.251-268 in M J Egenhofer, C Freska, and H J Miller (eds): GIScience2004. Right click to download.
59. R G Pontius Jr, E Shusas and M McEachern. 2004. Detecting important categorical land changes while accounting for persistence. Agriculture, Ecosystems & Environment 101(2-3) p.251-268. Right click to download.
60. R G Pontius Jr and Pablo Pacheco. 2004. Calibration and validation of a model of forest disturbance in the Western Ghats, India 1920-1990. GeoJournal 61(4) p.325-334. Left click to request a copy.
61. R G Pontius Jr and K Batchu. 2003. Using the relative operating characteristic to quantify certainty in prediction of location of land cover change in India. Transactions in GIS 7(4) p.467-484. Right click to download. The PDF of Pontius and Batchu (2003) is an electronic version of an article published in Transactions in GIS: complete citation information for the final version of the paper, as published in the print edition of Transactions in GIS, is available on the Blackwell Synergy online delivery service, accessible via the journal’s website at http://www.blackwellpublishing.com/tgis or http://www.blackwell-synergy.com.
62. R G Pontius Jr, A Agrawal and D Huffaker. 2003. Estimating the uncertainty of land-cover extrapolations while constructing a raster map from tabular data. Journal of Geographical Systems 5(3) p.253-273. Right click to download.
63. R G Pontius Jr. 2002. Statistical methods to partition effects of quantity and location during comparison of categorical maps at multiple resolutions. Photogrammetric Engineering & Remote Sensing 68(10) p.1041-1049. Right click to download.
64. R G Pontius Jr, J Cornell and C Hall. 2001. Modeling the spatial pattern of land-use change with GEOMOD2: application and validation for Costa Rica. Agriculture, Ecosystems & Environment 85(1-3) p.191-203. Right click to download.
65. L Schneider and R G Pontius Jr. 2001. Modeling land-use change in the Ipswich watershed, Massachusetts, USA. Agriculture, Ecosystems & Environment 85(1-3) p.83-94. Right click to download.
66. R G Pontius Jr and L Schneider. 2001. Land-use change model validation by a ROC method for the Ipswich watershed, Massachusetts, USA. Agriculture, Ecosystems & Environment 85(1-3) p.239-248. Right click to download.
67. R G Pontius Jr. 2000. Quantification error versus location error in the comparison of categorical maps. Photogrammetric Engineering & Remote Sensing 66(8) p.1011-1016. Right click to download.

PUBLICATIONS AS CONFERENCE PROCEEDINGS:

68. L Paladino and R G Pontius Jr. 2004. Accuracy assessment and uncertainty in baseline projections for land-change forestry projects. Conference Proceedings of the joint meeting of The Fifteenth Annual Conference of The International Environmetrics Society and The Sixth Annual Symposium on Spatial Accuracy Assessment in Natural Resources and Environmental Sciences. Portland ME. 11p. Right click to download.
69. R G Pontius Jr, L Claessens, C Hopkinson Jr, A Marzouk, E Rastetter, L Schneider, J Vallino. 2000. Scenarios of land-use change and nitrogen release in the Ipswich watershed, Massachusetts, USA. in B Parks, K Clarke, M Crane, editors. 2000. Conference proceedings of the 4^th international conference on integrating GIS and environmental modeling. Boulder: University of Colorado, CIRES.

PUBLICATION AS BOOK CHAPTERS:

70. R G Pontius Jr, J-C Castella, T de Nijs, Z Duan, E Fotsing, N Goldstein, K Kok, E Koomen, C D Lippitt, W McConnell, A Mohd Sood, B Pijanowski, P Verburg and A T Veldkamp. 2018. Lessons and Challenges in Land Change Modeling Derived from Synthesis of Cross-Case Comparisons. Chapter 8 in Martin Behnisch and Gotthard Meine (eds.) Trends in Spatial Analysis and Modelling. Geotechnologies and the Environment 19: 143-164. Springer International Publishing: Cham, Germany. Left click to request a copy.
71. Y Gao, R G Pontius Jr, N M Giner, T S Kohyama, M Osaki, K Hirose. Land Change Analysis from 2000 to 2004 in Peatland of Central Kalimantan, Indonesia Using GIS and an Extended Transition Matrix. Pages 433-443. Chapter 29 in M Osaki and N Tsuji (eds.) Tropical Peatland Ecosystems, Springer: Japan. ISBN 978-4-431-55680-0, DOI 10.1007/978-4-431-55681-7_29. Left click to request a copy.
72. D M Runfola, C Polsky, N Giner, R G Pontius Jr, C Nicolson. 2013. Future Suburban Development and the Environmental Implications of Lawns: A Case Study in New England, USA. Pages 119-141. Chapter in D Czamanski, I Benenson, and D Malkinson (eds.) Modeling of Land Use and Ecological Dynamics, Springer Berlin: Heidelberg. Left click to request a copy.
73. R G Pontius, S Menon, J Duncan, S Gupta. 2009. “Fundamentals for using Geographic Information Science to Measure the effectiveness of land conservation projects”. p.539-557. Chapter 23 in P K Joshi, P Pani, S N Mohaparta et al. (eds.) Geoinformatics for Natural Resource Management. Nova Science Publishers, New York NY. Left click to request a copy.
74. R G Pontius Jr and B Suedmeyer. 2004. “Components of agreement in categorical maps at multiple resolutions”. p.233-251. Chapter 17 in R S Lunetta and J G Lyon (eds). Remote Sensing and GIS Accuracy Assessment. CRC Press, Boca Raton FL. Right click to download.

PUBLICATION AS SOFTWARE MANUAL:

75. R G Pontius Jr and H Chen. 2006. GEOMOD Modeling. Chapter of help system in J Ronald Eastman. Idrisi 15: The Andes Edition. Worcester MA: Clark Labs. Right click to download.

You may be interested in the links below.

76. Scientific Curriculum Vitae of Gil Pontius
77. To compute your own summary statistics from a matrix, right click here and use “Save Target As” to download PontiusMatrix41.xlsx.
78. To get Yujia Zhang’s program to compute Incidents, right click here and use “Save Target As” to download Incidents01.xlsm.
79. To get Yujia Zhang’s program to compute States, right click here and use “Save Target As” to download States01.xlsm.
80. To create a figure for an ROC curve, right click here and use “Save Target As” to download TOCfigure1.xlsx.
81. To download Pontius’ TED talk, right click here and use “Save Target As” to download PontiusTED1.pptx.
82. To download the document that has ideas for an effective presentation, right click here and use “Save Target As” to download ClarityInOralForm07.doc.
83. To download the document that has ideas for an effective presentation, right click here and use “Save Target As” to download ClarityInOralForm11.pptx.
84. To download the document that has ideas for an effective paper, right click here and use “Save Target As” to download ClarityInWrittenForm03.doc.
85. To download a template for a scientific paper, right click here and use “Save Target As” to download format07.docx.
86. To download slides for my 2017 presentation at Hunan University, right click here and use “Save Target As” to download 2014GLPpontiusIntensity1.pptx.
87. To download slides for my 2014 GLP Berlin Session on Intensity Analysis, right click here and use “Save Target As” to download 2014GLPpontiusIntensity1.pptx.
88. To download slides for my 2018 AAG Presentation, right click here and use “Save Target As” to download AAG2018pontius01.pptx.
89. To download slides for my 2018 AAG Workshop, right click here and use “Save Target As” to download PontiusWorkshop.zip.
90. To download slides for my 2017 AAG Presentation, right click here and use “Save Target As” to download Pontius2017aag1.pptx.
91. To download slides for my Training on Intensity Analysis, right click here and use “Save Target As” to download IntensityAnalysisTraining04.pptx.
92. To download publications for my friends in China, right click here and use “Save Target As” to download PontiusForChina03.zip.
93. To download publications for my friends in Xiamen, right click here and use “Save Target As” to download LandChangeModeling01.pptx.
94. To download slides for my 2014 GLP Berlin Session on Best Practices, right click here and use “Save Target As” to download PontiusNRC1.pptx.
95. Many of the methods that I have created are available in the GIS software TerrSet, which is created by Clark Labs
96. See Clark Geography’s video album
97. See my alter ego, Doctor Stardust, The Award Winning Entertainer

SUMMARY OF PONTIUS’ INTELLECTUAL CONTRIBUTIONS:

Robert Gilmore Pontius Jr has developed quantitative methods that have contributed greatly to Geographic Information Science (GIS) and Remote Sensing. Pontius began his career as an applied statistician and environmental scientist with expertise in geographic information science (GIS), ecological modeling, and land change science. The applied nature of his diverse activities has inspired him to derive mathematical proofs for generally applicable concepts concerning spatial measurements that are essential in GIS and Remote Sensing. Several of these methods have been incorporated into the GIS & Image Processing software Idrisi, which has over 100,000 users worldwide.

Pontius’ most important intellectual creation is a conceptual philosophy to compare maps mathematically in ways that match visual intuition. One can understand the philosophy in the context of comparison of two maps that share the same set of categories, such as the comparison of maps of land classes from two time points or the comparison between ground information versus a classified map. The philosophy focuses on the disagreement between the maps because it is more important to understand the disagreement than the agreement for practical purposes, such as characterizing land change or improving a classifier. Pontius’ approach separates the overall disagreement between the maps into two components: quantity disagreement and allocation disagreement. Quantity disagreement is the amount of difference between the reference map and a comparison map that is due to the less than perfect match in the proportions of the categories. Allocation disagreement is the amount of difference between the reference map and a comparison map that is due to the less than maximum match in the spatial allocation of the categories, given the proportions of the categories in the reference and comparison maps. It is important to separate overall disagreement into these two components, because these two components have different interpretations and implications for practical applications. For example, if the purpose is to estimate change over time in overall forest area on a landscape, then quantity disagreement is much more important than allocation disagreement. Pontius (2000 & 2002) were the first publications in the sequence to establish this approach, while Pontius and Millones (2011) is the most recent and clearest articulation of this philosophy. Pontius, Shusas, and McEachern (2004) used the philosophy to derive new measurements to characterize transitions among categories in a manner that offers an alternative to conventional approaches. His philosophy formed the basis of Pontius and Spencer (2005), which won the Michael Brehney prize for best paper of the year in Environment and Planning B. Pontius and Cheuk (2006) used the philosophy to derive a cross-tabulation matrix that can analyze maps of categories where the pixels have categorical memberships that are mixed, soft or fuzzy. That paper was the most highly cited paper in its journal, IJGIS, during its first years of publication. Pontius and Connors (2009) built on that paper to show how associations among categories are sensitive to modifications in the spatial resolution of the maps. Pontius, Peethambaram, and Castella (2011) extended the philosophy to derive a method that compares simultaneously three maps of mixed pixels, which is essential for the validation of land change simulation models at multiple-resolutions. The approach has inspired additional methods to estimate land change over time from remotely sensed maps for the common case where map error is suspected but not measured due to lack of ground reference information (Pontius and Li 2010, Pontius and Lippitt 2006, Aldwaik and Pontius 2013). Pontius, Thontteh and Chen (2008) unified the philosophy for a categorical variable with the philosophy for a real continuous variable. Pontius and his doctoral students are now using his philosophy to design novel methods to construct rigorous methods for accuracy assessment of object-based classifications. His Bachelors, Masters, and Doctoral advisees have won awards from the Association of American Geographers more than 20 times. Pontius’ philosophy presents a new way of thinking, while his equations are elegant in their clarity.

Pontius spreads this philosophy in a variety of ways. He has presented it in workshops that he has given more than 20 times since 2003 in Australia, China, Ecuador, France, Germany, Greece, India, Japan, Mexico, Namibia, Nigeria, Russia, Portugal, Spain, The Netherlands, and the USA. The workshop teaches the approach in the context of land change modeling using Pontius’ model Geomod (Pontius, Cornell, and Hall 2001), which has become a standard model to predict land change especially for management of the global carbon cycle in the context of Reduced Emissions due to Deforestation and Degradation (REDD) projects. Pontius’ method has become popular in part because he has designed an easy-to-use spreadsheet, which is freely available from his web site www.clarku.edu/~rpontius. The electronic spread sheet is especially useful for accuracy assessment in Remote Sensing because the outputs derive from a single confusion matrix that users enter.

Pontius presents his philosophy strategically and theatrically to inspire a shift in the scientific culture from where scientists previously strived to report levels of accuracy that are better than random to where scientists now strive to report clearly the sizes of various types of disagreement that show how maps are less than perfect. This cultural shift in the mentality of scientists is as important as any particular quantitative method, because the shift in mentality is necessary for clear communication among scientists, hence is necessary for advancement in all aspects of GIS and Remote Sensing. Pontius has induced this shift in the profession by showing how his own maps have various types of errors, and then by demonstrating that his work is typical of the situation of many others (Pontius et al. 2008). Pontius designs all of his professional presentations at conferences to show these characteristics, with the direct purpose to serve as an example to others that it is necessary and advantageous to expose openly the disagreements among maps and to adopt more informative methodologies that are either compliments to or alternatives to conventional schools of thought.

He serves on the editorial boards of more than 10 journals and has been a reviewer for more than 116 different journals. He served on the National Research Council Committee concerning the Needs and Research Requirements for Land-Change Modeling.