HOW TO IMPORT GOOGLE EARTH ELEVATION (WITH HIGH ACCURACY) FOR TRIANGULATION IN OPEN ROADS DESIGNER

Question

Hello, 
 
 I want to do find earth work quantity for pre-bid project but don't have sufficient time to carry out topography survey. 
 
 So, i want to import data for triangulation from google earth with high accuracy. 
 
 kindly suggest,

vincent · Answer

Hi, 
 Google Earth Terrain has never been an accurate source of information (with a limitation of 400 Triangles whatever the surface in I remember well, besides low original resolution). To get worldwide elevation reference, you may download TIFs files for SRTM 1 Arc sec global from https://earthexplorer.usgs.gov/ as an example, and most countries have more accurate free open data. 
 So to get worldwide elevation, I would suggest to download TIFs from https://earthexplorer.usgs.gov/ - or google other sites - and use "Terrain from File" 
 
 March 2023 update: 
 There is an issue preventing correct import georeferenced elevation data as Terrains/STMS/4SMs in ORD if the DGN file itself is (or will be georeferenced). You have to strip data from GCS info before import, I explained Workflow with (free) GQIS here . 
 I still warn that "high accuracy" and "Google Terrain" or any freely available Satellite data (SRTM) do not match well... 
 Nowadays more accurate LiDAR Data/reality models are more and more available, and/or spending some money on a quick drone survey (as an example) and Terrain extraction with ContextCapture is a first step for reasonable outputs. 
 SRTM has 5 - 10 meters "accuracy", so please keep this in mind when using such data for infrastructure projects and designing your longitudinal profile. 
 With Modelers such as OpenRoads, you are "distorting" an existing surface. If your input surface is inaccurate, your design surface will be as inaccurate (you can add all the digits after the comma you want, they still will be all wrong). 
 And with SRTM data, inaccuracy is even before the comma (5.0 - 10.0 m ). 
 "Inaccuracy In", Inaccuracy Out" in short...