Site Suitability Analysis

Transcription

1 Alexandrea Bowman NRS 509 Site Suitability Analysis Going into the field to collect in situ data can be expensive, dangerous and take several trips before satisfactory data is collected. For archeologists, geologists, wildlife biologists, other field scientists and even policy makers this process can end up costing more money and more time than originally thought. Furthermore, graduate students are expected to finish course work and research in a stringent time frame (two years for most masters programs, four to eight years for many PhD programs), the expense and time spent in the field could make graduation time longer than expected and as a result, many students may find themselves without teaching or research assistantships (often times both last for only the required amount of time expected until graduation). Writing grant proposals, waiting to hear that a grant was or was not accepted, making travel plans and determining where to collect data are all time consuming processes. With funding becoming more competitive, new techniques should be analyzed and applied for field research. A Geographic Information System (GIS) site suitability analysis can shorten time in the field and lesson the expense of collecting in situ data by allowing the end user to analyze the field site without physically going there first. A GIS site suitability analysis uses a set of pre chosen criteria that is organized and layered in ArcGIS. Criteria can include geo hydrologic data, superimposed on soil erosion maps, like the process used by Nandi and Shakoor, in order to determine a specific goal. After all maps are collected, scale is chosen and then applied to all maps that are then layered in ArcGIS. The methods that are used are at the discretion of the end user, but can include Analytic Network Process (ANP) or Analytic Hierarchy Process (AHP) or any other multi criteria evaluation (MCE). The data is converted into raster format, a grid is selected (again this is at the discretion of the end user) and each cell is given a number (determined by the end user) that is directly related to the importance of the set criteria. For example, if an end user were looking for ground water containing arsenic, geo hydrologic maps and geo chemical maps would be super imposed and placed in a raster grid. Criteria could be a) no arsenic in ground water equals zero (meaning not important or not calculated) and b) arsenic detected in ground water equals one. The map that is then generated would then show only ground water that contains arsenic in a given watershed. Furthermore, if this particular study was being conducted to determine where drinking water wells should be located, local policy makers might be the people requesting the study. The final application of these processes (policy, lifequality assessment, land use data, etc.) should always be kept on mind when collecting and generating this type of data. GIS site suitability analysis can enable an end user to strategically predict where to locate specific fossils (Oheim, 2006), specific types of land use are most plausible (Reshmidev et al., 2009), identify forest restoration areas based (Orsi and Geneletti, 2009), what urban construction areas are safest (Xu et. al, 2010), landsides are most likely to occur (Nandi and Shakoor, 2009), land use planning in coastal areas (Pourebrahim et al., 2011), and where to put 1

2 incineration plants (Tavares, et. al, 2011). The possibilities for site suitability analysis are endless. And many different fields already use site suitability analysis for research and policy. A GIS site suitability analysis can influence policy makers when it comes to strategic land use planning (Reshmidev, et. al, 2009; Orsi and Geneletti, 2009). For instance, determining what land can be reforested while improving life quality and lowering cost to people and government can be tricky to evaluate. Risk analysis is almost always weighted against the cost analysis. GIS can calculate this analysis easily and at little cost. Hardware and software are relatively inexpensive in the long term for city planning (and most other uses). The most expensive cost would be paying someone to run the models and collect the data. However, this cost can be lessened if there is a willing graduate student as most universities have ArcGIS software on computer laboratory desk tops and there is always a need to collect data. Geology and topography are major considerations when dealing with field work. High, steep gradients can make it nearly impossible to collect data in a given area. Soil type and permeability are a direct result of rock type, erosion and sediment transport. Geologic hazards can also influence where buildings can be safely built and can include landslides, earthquakes, gradient and groundwater seepage (Nandi and Shakoor, 2009). These same geologic hazards can not only make field work difficult, if not impossible, but these same factors influence policy and cost of insurance for personal property. As noted by Kathryn Oheim, it can be difficult and expensive to access field sites. That expense increases if multiple trips or extended stays are required. Furthermore, geologists tend to work in remote areas and are subjected to the elements. Extended periods of time in openly exposed areas can lead to many different health problems and in some cases exposure to the elements can cause death. Many geologists have died in Antarctica due to hypothermia, getting lost, sudden and intense snow storms. Long term exposure in the field can be shortened by a site suitability analysis. GIS can enable end users to strategically locate specific areas of interest before field investigations begin. This cuts back on extended periods of time spent doing field work. As noted in the beginning of this paper, extended periods and multiple trips to the same location can cost a lot of money and waste time. Suitability analysis is a cost saving measure, as well as a time saving measure. The accuracy of site suitability analysis is directly proportional to how accurate the data collected and used is. With more data becoming available for public use, site suitability analysis itself has become a useful tool. Despite the usefulness of site suitability analysis and the extent to which it has been used in other fields, when it comes to using site suitability analysis in the deep ocean environment, planetary geology, igneous rock and metamorphic rock studies the literature is lacking and / or non existent. With rich and accurate data produced for almost every area on earth and other planets, one would expect to see a broader selection of literature containing topics related to the search for life in extreme environments on earth and other planets. This has not been the case. Currently, it seems that GIS site suitability analysis has only been used in applications that are directly related to research in sedimentary environments that deal with prediction of objects or occurrences rather than prediction of microbes in suitable environments. GIS suitability analysis has the potential to be used on Mars and Europa (currently the two most speculated areas to hold microbial life based on underground water and the possibility for chemosynthetic life) and areas under the sea floor greater than 10 cm in depth that have been speculated to hold chemosynthetic life. GIS site 2

3 suitability analysis can also be used in mineral prospecting in the deep oceans and on other planets, which has been discussed in recent years. The possibility of using this type of analysis can certainly lower the cost of collecting data using unmanned submersibles and even unmanned vehicles on other planets by collecting data in strategic places based on a set group of criteria. Annotated Bibliography Nandi, A. and Shakoor, A A GIS based landslide susceptibility evaluation using bivariate and multivariate statistical analysis. Engineering Geology 110, This paper focused on using a site suitability analysis in order to predict landslides in the Cuyahoga River watershed in northeastern Ohio. Bivariate and multivariate models were used in the study. The multivariate model showed the best results. The authors used a specific test area within a larger geographic area in order to determine if a site suitability analysis would work for landslide predictions. They knew where the landslides had occurred in the test area, but not in the larger geographic area that they were looking at. They combined LANDSAT from 1994 data with aerial photographs and landslide prediction maps. The authors admitted that the resulting maps would have been more accurate had they used newer LANDSAT data. Oheim, Kathryn B Fossil site prediction using geographic information systems (GIS) and suitability analysis: The Two Medicine Formation, MT, a test case. Palaeogeography, Palaeoclimatology, Palaeoecology 251, Kathryn Oheim successfully used a suitability analysis to locate fossils in The Two Medicine Formation in Montana. This particular study acknowledges the difficulties that field geologists can encounter due to inaccurate older maps and difficulties getting to field sites. Due to inaccuracies in older data, the author needed to make a trip to the field localities in question in order to create more accurate maps and to constrain the data. The difficulty in reaching field sites can be circumvented by using site suitability analysis for a particular field study or locality. Cost can also be reduced by using a site suitability analysis when looking for specific fossil types and is a successful tool to use for this purpose. Orsi, F. and Geneletti, D Identifying priority areas for Forest Landscape Restoration in Chiapas (Mexico): An operational approach combining ecological and socioeconomic criteria. Landscape and Urban Planning 94, This paper used socio economic considerations as part of the criteria to determine where reforestation would make the most amount of sense. Other considerations were soil erosion and proximity to roads, which could have a damaging effect on new growth. The 3

4 authors also looked at the probability of future land use to determine where and how much land could successfully be reforested. It was determined that almost 16,000 km 2 could be successfully reforested in the Chiapas. Pourebrahim, S., Hadipour, M. and Bin Mokhtar, M Integration of spatial suitability analysis for land use planning in coastal areas; case of Kuala Langat District, Selangor, Malaysia. Landscape and Urban Planning 101, This paper determined sustainable land use for a coastal area in Malaysia by using a GIS site suitability analysis. This paper was perhaps the most interesting that was read for this paper, as it combined socio economic considerations, existing land use, future land use and international, local and regional policy in order to determine the best areas for future land use and what that particular parcel of land should be used for. The final determination of the authors was that a large portion of the land should be responsibly managed for eco tourism, as that would both help the economy and conserve the most amount of coastal habitat for future use. Reshmidevi, T. V., Eldho, T. I. and Jana, R A GIS integrated fuzzy rule based inference system for land suitability evaluation in agricultural watersheds. Agricultural Systems 101, Reshmidevi et al., addresses the issues associated with land use planning and the ensuing complications. Because of the many geologic and geographic considerations and the addition of complicated policy issues, the authors point out that it can be quite difficult and challenging to determine land use. The authors created a GIS site suitability analysis by using experts in various fields as well as multiple kinds of raster and vector data. In the final maps that had been modeled, both land potential and water potential for agricultural land use had been taken into consideration. Tavares, G., Zsigraiova, Z. and Semiao, V Multi criteria GIS based siting of an incineration plant for municipal solid waste. Waste Management 31, Tavares et al., used a site suitability analysis to strategically determine where a solid waste incineration plant should be built on Santiago Island. The goal of the study was to minimize risk to human health and minimize cost to the local people who were already impoverished. The study successfully located a suitable place. The authors pointed out that the energy generated by a solid waste incineration plant could be used to desalinize water, one of the criteria used in the paper. The need for both a solid waste treatment plan and potable water in this particular area is an urgent need that the authors cited and took into consideration, as cholera and dengue fever are both prominent diseases that affect the less than one million people living on the island. Furthermore, where to build one of these types of 4

5 facilities was determined largely by economy and wind patterns (because of international laws citing air pollution and health concerns caused by fly ash). Xu, K., Kong, C., Li, J., Zhang, L. and Wu, C Suitability evaluation of urban construction land based on geo environmental factors of Hangzhou, China. Computers & Geosciences 37, Here Xu et al., used a GIS suitability analysis in order to determine safe areas to build in Hangzou, China. The major criteria that the authors took into consideration were soil type and earthquake probability. The resulting maps were to be used for land use planning and successfully determined the safest areas to build buildings on. Applications such as this have a practical use and can minimize loss of life and property. 5