城市测绘部门与城市基础地理平台

本文从我队五年经历出发,讨论城市测绘部门在UGIS(城市地理信息系统)中的地位和使命,探讨为UGIS提供基础地理数据平台问题.

Rocky Desertification Risk Zone Delineation in Karst Plateau Area:A Case Study in Puding County,Guizhou Province

Karst rocky desertification is a geo-ecological problem in Southwest China. The rocky desertification risk zone delineation could be used as a guide for the regional and hierarchical rocky desertification management and prevention. We chose the middle and lower reaches of the Houzhai underground basin on the karst plateau in Puding County, Guizhou Province, China as the study area and selected land use type, elevation, slope, aspect, lithology and settlement buffer as the main driving factors of the rocky desertification. The potential risk of rocky desertification was quantifed with the factor-weights union method and statistical analysis method. Five grades of rocky desertification risk were delineated based on Geographic Information System. The extremely low, low, moderate, high and extremely high rocky desertification risk zones accounted for 5.01%, 44.17%, 33.92%, 15.59% and 1.30%, respectively. As a whole, the rocky desertification risk level was moderate because the area of low and moderate rocky desertification risk zones occupied 78.09% of the study area. However, more than half of the area （about 50.81%） was predicted to have moderate rocky desertification risk and above, indicating that the study area was subject to rocky desertification. Rocky desertification risk was higher in the southeast and lower in the northwest of the study area. Distinct differences in the distribution of rocky desertification risk zones corresponding to different factors have been found.

Spatial Analysis of Flood Vulnerability Levels in Port Harcourt Metropolis Using GIS

The study identified spatial variations in flood vulnerability levels in Port Harcourt metropolis with the use of GIS （geographic information systems）. This study considered four factors and these included landuse types, drainage, residential densities and elevation. The elevation data and drainage data were derived from the topographical map of scale 1：35,000, while the land use types were derived from the imagery of Port Harcourt metropolis downloaded from Google Earth, 2010 version. Both the topographical map and imagery were geo-referenced to geographic coordinates and geographic features were digitized in form of shapefiles using both ArcView GIS 3.3 and ArcGIS 9.2 versions. AHP （analytical hierarchical process） was adopted in this study whereby many flood factors were ranked and overlaid for decision making. The contour data was used to generate the DEM （digital elevation model） through the process called kriging in ArcGIS 9.2. Based on the ranking index, factors considered were reclassified to three levels of vulnerability namely highly vulnerable, moderately vulnerable and lowly vulnerable through ranking method and these reclassified factors were then overlaid using an addition operator. The analysis shows that communities like Eagle Island, Ojimbo, Kidney Island were highly vulnerable to flood while communities like Choba, Ogbogoro, Rumualogu were moderately vulnerable. Communities like Rumuigbo, Rumuodomaya etc. were lowly vulnerable to flood. The highly vulnerable places covered 98.18 km2, moderately vulnerable was 220.46 km2 and lowly vulnerable areas covered 330.77 km2.

Regional Economic Types and Development Strategy of Small Towns in Suburb Beijing

The purpose of this article is to classify the regional economic types and development dynamics of small towns in suburb Beijing by applying the classification methods developed by Nelson's method and Location Quotient method into 183 small towns in Beijing.Four types of small towns are thus identified,including urban agriculture dominated towns,manufacturing dominated towns,service industry dominated towns and comprehensive type towns with balanced economic development.Within the environment of geographical information system,the spatial distribution pattern of four types of small towns with their evolution trend is analyzed.The results indicate that four types of small towns have obvious'core-periphery'spatial structure but with different functional orientations and evolution mechanisms.Based on this,the different development strategies for each type of small towns are summarized,providing a scientific reference for the differentiating planning and development strategies of these small towns.

Iron-Oxide Cu-Au Mineralizing Systems： Eastern Yakutia Perspective

The GIS （geographic information system） used for predicting the associated with upper-intrusive zone of hydrothermal alteration IOCG （iron-oxide copper gold） mineralizing systems is shown by example of the northeast of Russian. IOCG ore deposits can have enormous geological resources with significant reserves of base, precious and strategic metals, are economically attractive targets for mineral exploration worldwide, but are still unknown in the northeast Russian. It was localized in Tarinskiy ore node （eastern Yakutia） field of brecciated altered rocks with sulfide and iron-oxide cement is a first in eastern Yakutia nature anomaly of IOCG-type with iron-oxide Cu-Au ± U specialization, that was formed close to the surface of Rep-Yuruinskiy pluton. It should be of interest as a new precious metals world class deposit type in northeast of Russia.