摘要：Based on the developing tendency of present China’s basic GIS,this paper discusses the designing idea for scales of 1∶10 000,1∶50 000, 1∶250 000 and 1∶1 000 000 pyramid_like multi_layer and multi_resolution of the basic GIS.A technical line for the construction of basic GIS of the whole country and various provinces for sustainable development is put *** some important theoretical GIS issues touched by the technical process are discussed.

摘要：The Mongolian Plateau,a vital ecological barrier in northern China,is of great importance for studying vegetation dynamics in Mongolia against the background of climate *** studies can enhance our understanding of regional vegetation responses to global warming and contribute to the establishment of a stronger ecological barrier in northern ***,we analyzed the spatial and temporal characteristics of the NDVI(normalized difference vegetation index)in Mongolia using 8 km resolution GIMMS NDVI3g data from 1990 to 2022,along with temperature,precipitation,and elevation *** analysis and correlation methods were used to examine the relationships between the NDVI and temperature,as well as *** results showed four important aspects of these relationships.(1)The NDVI in Mongolia increased significantly from 1990 to 2022 at a rate of 0.0015 yr^(-1)(P<0.05).(2)Mongolia’s NDVI increased from 1990 to 2022 in 60.73%of the *** this total,the area with a significant increase accounted for 31.67%and was concentrated on the eastern and western *** area experiencing a significant decrease accounted for 15.67%and was mainly located on the southwestern edges.(3)The NDVI analysis revealed significant increasing trends in all regions except for those at elevations of 1500-2000 *** greatest rate of increase was observed between 500 and 1000 m,and the increasing trend weakened as elevation continued to increase before gradually becoming significant ***,the NDVI increased significantly across different slopes,and the rate of increase decreased as the slope increased.(4)From 1990 to 2022,Mongolia’s NDVI was mostly negatively correlated with *** occurred over 66.75%of the total land area,with 17.21%of the region exhibiting a significant negative correlation,mainly in the ***,the NDVI demonstrated a positive correlation with precipitation,encompassing 86.71%of the total land *** 4

摘要：介绍了一种新的输出线路的设计方法。该方法使用X3D中elevation Grid、Inline等相关节点设计能在网上显示的输电线路及地貌环境,从而达到虚拟现实的效果。此设计能在IE浏览器或BS Contact浏览器中显示三维的输电线路及周边的真实地貌环境,对基于B/S结构的电力系统GIS设计有着重要的现实意义。

摘要：The minimum curve radius is one of the most important factors in railway route design. The minimum curve radius of the Hainan East Ring Railway, a newly built high-speed passenger-dedicated line from Haikou to Sanya, Hainan, China, was determined through comparative analysis of the design codes both in China and Germany. The results show that the design parameters of the Hainan East Ring Railway in terms of the minimum curve radius determined by China＇s Temporary Regulations, conform to the ones by German code, and even preserve some capacity for speeds up to 300 km/h in the future. Additionally, the related counter- measures for speed increases in this line were proposed on the premise of the safety and riding comfort of the trains.

摘要：本文从理论的推导来探讨电磁波测距图根三角高程测量的边数。这在实际工作中具有重要的意义。无论是理论推导,还是我单位多个测区的实践证明,图根三角高程按图根导线布设,其精度可满足《城市测量规范》的要求。