datum level是什么意思

用法例句

Approach to GPS Elevation Fitting Precision;

对GPS高程拟合精度的探讨

Heterogeneity of landscape pattern with elevation in karst area;

喀斯特区域景观空间格局随高程的分异特征

Enhancing Spatial Prediction of Soil Properties Using Elevation;

用高程辅助提高土壤属性的空间预测精度

But the accuracy of GPS altitude control surveying is not very satisfied sometimes.

在矿山建设和生产的测量工作中,GPS定位是目前地面控制的常用方法,但由于在高程精度方面尚不理想。

Good quality of such kind of base can be achieved by control of cement dose, altitude, paving length , capaction times and curing, further improvement of construction quality.

根据稳定砂砾的特点，阐述了对机械摊铺水泥稳定砂砾的监理体会，从对其质量、水泥剂量、高程等方面的控制，进一步改善此类基层的施工质量，对作业面长度、碾压次数、养生等因素的管理，达到机械摊铺水泥稳定砂砾基层的良好程度。

Fining the earth water level,heighten GPS height survey precision;

精化大地水准面 提高GPS高程测量精度

The Application of the Method of Dual Instruments in Height Resurvey and Control Survey;

双仪器法在高程复测和控制测量中的应用

Investigation on the height repetition determination of Qomolangma peak;

珠峰高程复测有关问题的探讨

Analysing the features of the advanced measurement instrument — the total station,the measurement principle of the trigonometric levelling and the error,the paper puts forward to use the total station trigonometric levelling in the mining area has advantages such as free from landform,small error,high precision,great efficiency,etc.

通过对先进的测量设备——全站仪的特点、三角高程测量原理及其误差的分析,提出在矿区采用全站仪进行三角高程测量,不受地形限制,具有误差小、精度高、效率快等优点,可代替四等水准测量。

The checking items have basic control point,near shaft point for orientation and elevation starting point,shaft mouth coordinate,underground traverse point and elevation starting point,underground roadway and productive workings extension.

检测项目包括基本控制点、近井点和高程基点、井口坐标、井下导线点及高程基点、井下巷道及采区范围,并根据有关规范推算其测量精度及误差范围,进而对矿山原有资料进行评述。