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GEOSTATS: assessing socioeconomic factors influence in deforestation

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  • jeanfmas@balamku.uacam.mx
    We are studying deforestation in the State of Campeche (South east of Mexico). Overlaying two forest maps of different dates, we generated a digital map which
    Message 1 of 1 , Jan 20, 1997
      We are studying deforestation in the State of Campeche (South east of
      Mexico). Overlaying two forest maps of different dates, we generated
      a digital map which represents the evolution of forest areas. Classes
      of this digital map are non forested areas, unchanged forest areas
      and deforested areas. As a following step, we tried to find out the
      relationship between deforestation and environmental and
      socioeconomic factors such as distance from settlements and
      characteristics of the population.

      Socioeconomic data we used are organized by localities (data are
      given for each settlement), the problem is how to deal with both
      point data and surface data within a GIS. In order to represent the
      influence of a settlement on its environment we developed a simple
      model which is based on two simplifying assumptions: the influence of
      a settlement a) depends on its characteristics and b) decreases with
      the distance from it.

      In order to develop the model, localization of each settlements was
      captured in a point cover, then the settlements point cover was
      converted to a grid using. The value assigned to
      the grid cells was the value of a selected property (for example
      number of people of the settlement) according to the point of its
      overlay. If no points fell within the cell, a zero value was
      assigned. Then a low pass filter was applied to the grid. The size of
      the filter and the coefficients used to weight the average towards
      the pixels were derived from the function that described the
      relationship between deforestation and distance from settlements
      pointed out in a previous step. Several layers were generated
      developing the model with different socioeconomic features. Values of
      the model layers were then grouped into ten classes representing
      similar area and rate of deforestation was calculated for each of
      them. Coefficient of correlation between the values of the model and
      the rates of deforestation were calculated. Analysis of the
      coefficients of correlation allows to determinate the relative
      influence of the different socioeconomic characteristics we
      integrated in the model on deforestation rates.

      I have some doubts about the model and the interpretation of the
      results: a) linear correlation is not always the more appropriate to
      estimate the relationship between the variables,is there a better way
      to estimate relation between two variables ? b) the studied
      socioeconomic variables presented correlation between them, there is a
      way to separate them ? c) the variable the model deals with is a
      combination of a sociological variable and the distance (because of
      the filtering), can be the variable "distance" be eliminated to
      analyze the pure socioeconomic variable ? Any suggestions or
      references about how to deal with socioeconomic point data and modeling
      influence of populated areas on its environment are welcome.


      *************************************************
      Jean-Francois Mas
      Laboratorio de Percepcion remota y SIG
      Programa EPOMEX
      Universidad Autonoma de Campeche
      AP 520 CP 24030 CAMPECHE, CAMP, MEXICO

      Tel (52) (981) 11600
      Fax (52) (981) 65954

      E-mail jeanfmas@...
      WWW : epomex.uacam.mx
      *************************************************
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