For a georeferenced project, choosing the spatial reference system is important for the web application. The spatial reference system impacts the 3D visualization and the coordinates’ management in the web application.

You must select a spatial reference system with metric coordinates, appropriate for 3D visualization. We recommend to use ENU systems, or standard UTM/WGS 84 projections.

For coordinates’ management, the ContextCapture web application has its own, fairly limited, spatial reference system (SRS) database. The web viewer SRS database is limited to ENU systems and standard EPSG projections, and does not handle vertical datum. The Z value will be displayed as is in the web application, in the general case using the ellipsoid as reference.

If you want the web application to display orthometric heights, you should produce the 3MX with a spatial reference system with a suited vertical datum (eg. EGM96).