Establishing a framework for Open Geographic Information science

When conducting research within a framework of Geographic Information Science (GISc), the scientific validity of this work can be argued as highly dependent upon the extent to which the methods employed are reproducible, and that, in the strictest sense, can only be fully achieved by implementing transparent workflows that utilize both open source software and openly available data. After considering the scientific implications of non-reproducible methods, we provide a review of both open source Geographic Information Systems (GIS) and openly available data, before describing an integrated model for Open GISc. We conclude with a critical review of this embryonic paradigm, with directions for future development in supporting spatial data infrastructure.     

Evaluating digital elevation models for glaciologic applications: An example from Nevado Coropuna, Peruvian Andes

This paper evaluates the suitability of readily available elevation data derived from recent sensors – the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and the Shuttle Radar Topography Mission (SRTM) – for glaciological applications. The study area is Nevado Coropuna (6426 m), situated in Cordillera Ampato of Southern Peru. The glaciated area was 82.6 km² in 1962, based on aerial photography. We estimate the glacier area to be ca. 60.8 km² in 2000, based on analysis of the ASTER L1B scene.We used two 1:50,000 topographic maps constructed from 1955 aerial photography to create a digital elevation model with 30 m resolution, which we used as a reference dataset. Of the various interpolation techniques examined, the TOPOGRID algorithm was found to be superior to other techniques, and yielded a DEM with a vertical accuracy of ± 14.7 m. The 1955 DEM was compared to the SRTM DEM (2000) and ASTER DEM (2001) on a cell-by-cell basis. Steps included: validating the DEM's against field GPS survey points on rock areas; visualization techniques such as shaded relief and contour maps; quantifying errors (bias) in each DEM; correlating vertical differences between various DEM's with topographic characteristics (elevation, slope and aspect) and subtracting DEM elevations on a cell-by-cell basis.The RMS error of the SRTM DEM with respect to GPS points on non-glaciated areas was 23 m. The ASTER DEM had a RMS error of 61 m with respect to GPS points and displayed 200–300 m horizontal offsets and elevation ‘spikes’ on the glaciated area when compared to the DEM from topographic data.Cell-by-cell comparison of SRTM and ASTER-derived elevations with topographic data showed ablation at the toes of the glaciers (− 25 m to − 75 m surface lowering) and an apparent thickening at the summits. The mean altitude difference on glaciated area (SRTM minus topographic DEM) was − 5 m, pointing towards a lowering of the glacier surface during the period 1955–2000. Spurious values on the glacier surface in the ASTER DEM affected the analysis and thus prevented us from quantifying the glacier changes based on the ASTER data.     

Building Environmental Literacy through Participation in GIS and Multimedia Assisted Field Research

Abstract

A Learning Support System (LSS) that emphasizes experiential research in natural environments using the cutting-edge technologies of GIS and multimedia has been developed for teaching environmental literacy to undergraduate students at the University of Georgia. Computers are used as cognitive tools to create a context in which students become interns in an ecological research center. Students are instructed to conduct research in the form of two field laboratories (the stream and forest laboratories). They accomplish their tasks by collecting data in the field (the State Botanical Garden of Georgia near the campus). They enter the data in the Learning Support System (LSS), and are guided to formulate hypotheses relating to stream water quality and human impact on forest succession for testing. Students also interact with the Environmental Research Support Site (ERSS) within the LSS for explanations to their findings. A specially customized Arc View GIS program within the LSS provides a tool to students for spatial analysis in the case of the forest laboratory. Students and faculty evaluations as well as final examination results confirmed the receptiveness of students to the LSS approach and its effectiveness in the learning of environmental literacy.     

Commuting and Gender in Italy: A Methodological Issue*

Commuting in Italy has always been addressed without regard to gender differences. Following the issuance of a comprehensive database by the National Statistical Institute, it is now possible to analyze gender differences in personal mobility for the first time in Italy. For our analyses we used Local Labor Systems (LLS) zoning in lieu of administrative zoning. LLSs are territorial subdivisions based on the principle of a self‐contained labor market and are widely used in Italy. This article also reports the results of a multidimensional data analysis aimed at highlighting relations between different gender‐based commuting patterns and a set of variables (education level, age, household structure, occupational category, and position, etc.). The analysis points out gender differences in the relationship among commuting and socioeconomic characteristics, reveals that these relationships are in turn related to the economic structure and geographical context of different regional labor markets, and suggests to analysts that they be sensitive to singular context when interpreting the meaning of gender differences in commuting.     

起伏地形下重庆降水精细的空间分布

采用重庆地区34个气象观测站1971—2000年30 a平均月降水总量资料,以及重庆地区100 m×100 m DEM(D igital E levation Model)数据,对重庆地区降水空间分布进行研究。根据山地气候学原理,利用GIS(Geographical Information Systems)软件,分析降水空间分布的影响因子,建立平均月降水量空间估算模型,计算了平均月降水量的空间分布。结果表明:随着海拔高度的增加,降水量逐渐增加;各月降水量的最大值出现在东北山区;降水量的季节变化明显。     

米仓山西段晚元古代-古生代层序地层及地层模型

米仓山西段位于扬子地台北缘，该区除缺乏泥盆系和石炭系外，各时代地层均有发育。从震旦系灯影组至二叠系大隆（或长兴）组可划分出１３个相当于Ⅱ～Ⅲ级沉积旋回的层序或复合层序，并建立了地层模型。地台边缘的层序地层和沉积体系域具有它自身的某些特点。由局部构造活动引起的相对海平面变化，对沉积体系域和界面类型有着明显的影响。但是，在这种情况下形成的沉积序列和其它特征，与相应的典型体系域相比有一定的差异。为此，我们引用或引入了上超体系域（ＯＳＴ）、滨浅海边缘楔（ＳＭＷ）、最大海泛沉积层（ＭＦＳ）和Ⅲ类层序界面等概念。     

陆相坳陷型和断陷型湖盆层序地层样式探讨

依据层序地层学基本理论,考虑中国中新生代陆相坳陷型和断陷型湖盆的盆地结构和沉积物充填序列特征,综合利用地质和地球物理资料,以松辽盆地白垩系和准噶尔盆地侏罗系、柴达木盆地第四系和渤海湾盆地第三系为研究实例,将坳陷型湖盆沉积层序细分成可以确定首次湖泛面和不能确定首次湖泛面的两种类型,建立了这两种类型湖盆的层序地层样式。前者由低位、湖侵和高位体系域组成,后者由湖侵和湖退体系域构成。在断陷型湖盆中,可将盆地缓坡由同生断裂活动造成的地势变化带作为地形坡折带(构造坡折带)并用于确定首次湖泛面,进而讨论了首次湖泛面和最大湖泛面的多种识别标志,建立了由低位、湖侵和高位体系域构成的断陷型湖盆层序地层样式。