The countrywide historical gravity dataset of Lithuanian territory

The historical gravity dataset of Lithuania consists of two files: data of second and third order gravimetric network as well as data of gravity survey. Raw data were collected by digitising the paper catalogues of gravimetric network stations and sheets of gravimetric map at a scale 1:200000. Gravity data set covers total territory of Lithuania (65 thousand square km). Initially the gravity data were in Potsdam gravity system, geodetic coordinates of the gravity points – in the coordinate reference system Pulkovo 1942 (EPSG:2499), and the geodetic heights of gravity points – in the Baltic normal height system of 1977 (EPSG code 5705). In the final countrywide set the gravity data are in the International Gravity Standardization Net of 1971 gravity system, geodetic coordinates – in European Terrestrial Reference System of 1989 coordinate reference system (EPSG:4258), and geodetic heights – in the European Vertical Reference System of 2007 (EPSG:5215). Total number of gravimetric network stations is 123, and total number of gravity survey points is 10660. The data were recorded into files applying DBF (Data Base Format) format: LTU_GNS.DBF - Gravity Network Stations data;LTU_GSP.DBF - Gravity Survey Points data.立陶宛历史重力数据集包含两类文件：二等与三等重力测量网数据，以及重力勘探数据。原始数据通过数字化比例尺为1:200000的重力测量站纸质目录与重力图图幅采集得到。该数据集覆盖立陶宛全境（6.5万平方千米）。初始阶段，数据集采用波茨坦重力系统（Potsdam gravity system）存储重力数据，重力点大地坐标采用普尔科沃1942坐标系（Pulkovo 1942, EPSG:2499），重力点大地高程采用1977年波罗的海正常高系统（Baltic normal height system of 1977, EPSG:5705）。最终版全国数据集的重力数据采用1971年国际重力标准网系统，大地坐标采用1989年欧洲大地参考系（EPSG:4258），大地高程采用2007年欧洲垂直参考系（EPSG:5215）。数据集内重力测量站总计123个，重力勘探点总计10660个。数据采用DBF（数据库格式，Data Base Format）存储，具体文件包括：LTU_GNS.DBF为重力测量站数据文件，LTU_GSP.DBF为重力勘探点数据文件。