EXPERIENCE OF OBTAINING INITIAL DATA FROM GOOGLE EARTH TO BUILD A DIGITAL TERRAIN MODEL

Abstract

The Google Earth information system is the virtual globe built on connected photographs with terrain information and partially vectorized situation. The system has the ability to obtain information on the WGS-84 coordinates and the universal transverse Mercator projection of any point, but it requires research on the methodology for obtaining such information and the accuracy of spatial information. The answers to these questions will make it possible to specify the range of geodetic and design tasks that can be solved with Google Earth. It has been analyzed the latest research and publications in article. According to this analysis, the problem of using the Google Earth system for geodetic purposes remains relevant. The work focused on the formation of initial data from the Google Earth system in a convenient text format for further loading into a computer-aided design system to create a digital terrain model. An algorithm for obtaining initial data in the form of four columns has been compiled: the name of the point and three coordinates. In this format, you can perform any coordinate transformations with subsequent loading into other programs. The algorithm for obtaining initial data from Google Earth in text format will be as follows: 1) drawing up a plot survey scheme (determining the survey boundary, alphanumeric designation of streets for simplicity, highlighting survey objects, etc.); 2) creation of closed polygons (general survey area, all areal objects), polylines (all linear objects), marks (all point objects); 3) obtaining geodetic coordinates of nodes of areal objects and polylines; 4) creation of longitudinal profiles for finding heights. The problem of assessing the errors of the Google Earth system in the horizontal plane remains relevant in order to be able to form a digital model of the situation.