GIScience & Remote Sensing ISSN: 1548-1603 (Print) 1943-7226 (Online) Journal homepage: https://www.tandfonline.com/loi/tgrs20 Intensity Analysis to communicate land change during three time intervals in two regions of Quanzhou City, China Bin Quan, Robert Gilmore Pontius Jr & Hui Song To cite this article: Bin Quan, Robert Gilmore Pontius Jr & Hui Song (2019): Intensity Analysis to communicate land change during three time intervals in two regions of Quanzhou City, China, GIScience & Remote Sensing, DOI: 10.1080/15481603.2019.1658420 To link to this article: https://doi.org/10.1080/15481603.2019.1658420 Published online: 16 Sep 2019. Submit your article to this journal Article views: 14 View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=tgrs20 GISCIENCE & REMOTE SENSING https://doi.org/10.1080/15481603.2019.1658420 Intensity Analysis to communicate land change during three time intervals in two regions of Quanzhou City, China Bin Quan a, Robert Gilmore Pontius Jr b and Hui Song c aDepartment of Geography and Geographical Information System, Hengyang Normal University, College of City and Tourism and HIST Hengyang Base of UNESCO, Hengyang, Hunan, China; bClark University, School of Geography, Worcester, MA, USA; cShanxi Wocheng Institute of Ecology and Environment, Big Data Research Center, Taiyuan, Shanxi, China ABSTRACT ARTICLE HISTORY Intensity Analysis is a mathematical framework to express differences within a set of categories Received 27 February 2019 that exist at multiple time points. The original version of Intensity Analysis communicated land Accepted 17 August 2019 change in one region during time intervals that have various durations. Our new manuscript KEYWORDS fi ’ modi es Intensity Analysis equations and graphics to compare various regions during time GIS; Intensity Analysis; land intervals that have the same duration. This manuscript also combines Intensity Analysis with change; Quanzhou City; a method to express change as the sum of three components: quantity, exchange, and shift. We China; region give two new insights concerning interpretation, which apply also to the original version of Intensity Analysis. First, we quantify the proportion of each change that is attributable to the start size of the category versus the deviation from a uniform intensity. Second, we clarify that a category’s gain intensity expresses the percentage of the category’s end size that derives from the gain during the time interval, while a category’s uniform transition intensity indicates the aggressiveness of the category’s gain. We illustrate the approach by comparing the Inland versus the Coastal regions of Quanzhou City, China. Inputs are GIS maps at 1995, 2000, 2005, and 2010 that show six land categories: Built, Cultivated, Forest, Garden, Unused, and Water. Change as a percentage of the Coastal region is greater than change as a percentage of the Inland region during each time interval. Exchange between categories is the largest component of change in each region during each interval. Cultivated loses and Built gains more intensively than the uniform change intensity in each region during each time interval. Built’s gain targets Cultivated intensively in each region during each interval. Built’s targeting explains most of the transition from Cultivated to Built in the Inland region, while Cultivated’s size explains most of the transition from Cultivated to Built in the Coastal region. If the data are sufficiently accurate, then these results strengthen the concern for the transition from Cultivated to Built, as the loss of Cultivated land threatens food security in China. Scientists can apply Intensity Analysis by using free software available at www.clarku.edu/~rpontius. 1 Introduction numbers that is daunting to interpret. Intensity Analysis is an accounting framework to structure inter- The transition matrix is the foundation for many metrics pretation by communicating mathematically and gra- that analyze temporal change within a set of categories. phically the information in transition matrices (Aldwaik The matrix is a table of numbers where the rows show and Pontius Jr 2012, 2013). Intensity Analysis distin- the categories at the start of the time interval while the guishes between size and intensity. Size is area in the columns show the same sequence of categories at the context of landscapes. Intensity is a ratio, where the end of the time interval. In the matrix, each diagonal numerator is a change’s size and the denominator is entry shows the size of persistence of a category, while the size of the extent where the change could have each off-diagonal entry shows the size of transition possibly occurred. Intensity Analysis explains a change’s from one category to a different category. If an applica- size as a product of two factors: the size of the spatial tion has two time points, then one transition matrix extent and the intensity of the change. A category’s net summarizes the changes during the time interval. change is its gain minus its loss. If a category loses in Scientists frequently need to compare regions during some places while it gains in other places, then its net several time intervals (Pontius Jr et al. 2017b). In such change is less than its gross change, because cases, several transition matrices can form a wall of CONTACT Robert Gilmore Pontius Jr Email: [email protected] Classification: Land Cover and Land Use; Dynamics; Multitemporal Analysis and Change Detection; Land Cover and Land Use (Change); Time Series Analysis. Recommended Editorial Board Members Douglas Stow, Soe Myint © 2019 Informa UK Limited, trading as Taylor & Francis Group 2 B. QUAN ET AL. a category’s gross change is its gain plus its loss. Y might gain from X more intensively than from the Pontius Jr and Santacruz (2014) established concepts other categories at the start time. In some cases, both that distinguish between net change and gross change reasons might exist. Intensity Analysis quantifies these by specifying three components: quantity, exchange, possible reasons. Intensity Analysis gives insights to the and shift. The quantity component is the absolute patterns of change so that subsequent analysis can value of net change. The exchange component occurs focus on the relevant processes of change. Scientists when some places experience a transition from one must understand the patterns in order to research the category to another category, while different places processes. Planners must understand the processes in experience the opposite transition between the two order to manage the landscape. Modelers must under- categories, thus contributing zero net change for both stand the patterns and processes in order to simulate categories. The shift component is the total change an extrapolation of recent trends. Our Discussion sec- minus the quantity and exchange components. Shift is tion shows how the concepts of Intensity Analysis relate a type of allocation difference where a category X loses to the simulation of future scenarios. to a second category while X gains from a third cate- A literature review shows that Intensity Analysis is gory. Components of difference were not part of useful to understand change, while researchers could Intensity Analysis’ original version, which considered benefit even more from our modifications that include one region during time intervals that have various components of difference and comparison of regions durations. Our article presents modified equations for during several time intervals. Authors have used the various regions in a time series where each interval has original version of Intensity Analysis to analyze land the same duration. The modified equations are more change where the spatial extent is a single region elaborate concerning space because they account for (Minaei, Shafizadeh-Moghadam, and Tayyebi 2018; various regions. The modified equations are simpler Yang et al. 2017). Our modifications to Intensity concerning time because they do not need to account Analysis would have been helpful to scientists who for variation in duration of the time intervals. The pur- compare regions of various sizes (Rafiqul, Giashuddin pose of our manuscript is to modify Intensity Analysis Miah, and Inoue 2016; Liu et al. 2014). Some scientists to integrate components of difference and compare measure net change by category, which can miss the regions during time intervals that have the same majority of gross change (Jokar Arsanjani 2018). duration. Difference components reveal the portion of gross This manuscript’s modifications to Intensity Analysis change that net change constitutes (Shafizadeh- continue to organize the patterns of change in Moghadam et al. 2019). Many scientists express transi- a hierarchical structure, identical to the original version. tions among categories in the form of Markov matrices The hierarchy has three levels: interval, category, and (Awotwi et al. 2018; Berlanga-Robles and Ruiz-Luna transition. The interval level compares time intervals in 2011). Markov matrices show ratios that express the terms of gross change. The category level compares the same concept as Intensity Analysis’ transition intensi- categories’ losses and gains during each time interval. ties. However, Markov matrices do not show the sizes of The transition level compares how each category gains the transitions; thus, Markov matrices alone do not from other categories during each time interval.