排序方式: 共有8条查询结果,搜索用时 15 毫秒
1
1.
2.
Invasive species pose global biological and economic challenges. Over the past four decades, Prosopis taxa have emerged as a major invader of the arid and semi-arid regions of the world. Prosopis juliflora, one of the highly invasive Prosopis species, is dominantly present in the Afar region of Ethiopia and continues to spread into the surrounding areas. The objective of this study was to aid the mapping, utilization, and management of the invasive P. juliflora in Afar, by employing participatory research techniques. We assessed the introduction history, impacts, uses, and control strategies of invasive P. juliflora by interviewing 108 pastoralists and agro-pastoralists. In addition, we used Participatory Mapping (PM), Geographic Information Systems (GIS), Global Positioning System (GPS), and remote sensing technologies and approaches to map sites invaded by P. juliflora. Sketch maps were produced by men, women, pastoralist and agro-pastoralist groups. Experts aggregated, scaled and reproduced the sketch maps with support from the Afar communities. We provided GPS and GIS trainings to selected community members who assisted us in collecting the GPS locations of more than 70 key features and landmarks. The sketch maps were digitized and geo-referenced by experts using the 70 GPS records as control points. Geo-referenced community maps were superimposed on pan-sharpened Landsat 8 satellite images and presented to the communities for verification. We overlaid the verified community maps on ancillary land-cover layers, and detected the land-cover classes that were most affected by P. juliflora invasion. Despite its uses as source of fire wood, charcoal, and animal fodder, the species has adverse impacts on native species and livestock resources. Afar communities mapped P. juliflora infestations, particularly those that occurred near their villages, using high and moderate density classes. The two highly invaded land-cover categories were dense grassland, and exposed sand & soils. Participants collaborated in creating the produced maps, suggesting that participatory research approaches are another tool for early detection of invasive species and guiding fine-scale management strategies. 相似文献
3.
结合Sketch Up建模软件和VRP可视化仿真应用软件,实现了南京信息工程大学虚拟数字校园模型构建与交互式浏览;讨论了校园3维模型构建中的数据需求、数据获取方法,以及用VRP实现交互式浏览应注意的一些问题。 相似文献
4.
5.
Jia Wang Michael Worboys 《International journal of geographical information science》2017,31(9):1697-1721
In this paper, we present a systematic approach to sketch map interpretation. The method decomposes the elements of a sketch map into a hierarchy of categories, from the material sketch map level to the non-material representational sketch map level, and then interprets the sketch map using the five formal representation spaces that we develop. These spaces (set, graph, metric and Euclidean) provide a tiered formal representation based on standard mathematical structures. We take the view that a sketch map bears information about the physical world and systematises this using extensions of existing formal ontologies. The motivation for this work is the partially automatic extraction and integration of information from sketch maps. We propose a set of ontologies and methods as a first step in the direction of a formalisation of partially automatic extraction and integration of sketch map content. We also see this work as a contribution to spatial cognition, where researchers externalise spatial knowledge using sketch mapping. The paper concludes by working through an example that demonstrates the sketch map interpretation at different levels using the underlying method. 相似文献
6.
针对大范围建筑物高度信息的提取精度低且速度慢的问题,提出利用GOOGLE Sketch Up模型法,模拟沈阳市2014-09-22T10∶30∶00不同位置、不同高度的建筑及阴影,对此情况下基于阴影长度法测算的建筑高度误差变化规律进行研究。结果表明:测试点经度变化或纬度变化时,建筑高度测算误差都随着与中心样本点的距离增加而增大,且误差随纬度变化的幅度大于随经度变化;测试点经纬度同时变化,建筑高度测算误差随着与中心样本点的距离增加而增大,且沿西北—东南方向变化幅度大于沿东北—西南方向;同一位置,测算误差随建筑高度增加而增大。研究结果对提高阴影长度法的精度以及快速准确获取大范围建筑物高度信息等研究有参考价值。 相似文献
7.
Sketch mapping has been an important data collection technique for geographers since the 1960s. Structured sketch mapping requires participants to draw spatial data onto a base map containing cartographic information, in order to assist with spatial referencing. A concern that base map characteristics may influence sketch map content has been raised repeatedly in the research literature. However little scholarly attention has been paid to systematically testing the effect of base maps.This paper aims to test the effects of base map size and imagery on structured sketch maps of avoidance behaviour in university students. Using an experimental design, 272 sketch maps were compared for differences in: sketch map style; the location of collective avoidance hotspots; the extent of the reported area avoided; the number of reported areas avoided; the intensity of avoidance; and the tortuosity of sketch map features.No significant differences were found between base maps in sketch map style or the size, intensity or number of areas avoided. Provision of larger base maps caused respondents to draw more detailed sketch maps. Collective avoidance hotspots shifted location slightly between base maps, probably due to difficulties interpreting aerial photographs.Sketch map content appears to be remarkably robust to changes in base map. Base maps appear to assist respondents with spatial referencing rather than cueing respondents to report specific features. 相似文献
8.
1