Function proj_grid_info

ThirdParty/libproj/vtklibproj/src/4D_api.cpp:1723–1793

/

/*****************************************************************************/
PJ_GRID_INFO proj_grid_info(const char *gridname) {
/******************************************************************************
    Information about a named datum grid.

    Returns PJ_GRID_INFO struct.
******************************************************************************/
    PJ_GRID_INFO grinfo;

    /*PJ_CONTEXT *ctx = proj_context_create(); */
    PJ_CONTEXT *ctx = pj_get_default_ctx();
    memset(&grinfo, 0, sizeof(PJ_GRID_INFO));

    const auto fillGridInfo = [&grinfo, ctx, gridname]
                        (const NS_PROJ::Grid& grid, const std::string& format)
    {
        const auto& extent = grid.extentAndRes();

        /* name of grid */
        strncpy (grinfo.gridname, gridname, sizeof(grinfo.gridname) - 1);

        /* full path of grid */
        pj_find_file(ctx, gridname, grinfo.filename, sizeof(grinfo.filename) - 1);

        /* grid format */
        strncpy (grinfo.format, format.c_str(), sizeof(grinfo.format) - 1);

        /* grid size */
        grinfo.n_lon = grid.width();
        grinfo.n_lat = grid.height();

        /* cell size */
        grinfo.cs_lon = extent.resX;
        grinfo.cs_lat = extent.resY;

        /* bounds of grid */
        grinfo.lowerleft.lam  = extent.west;
        grinfo.lowerleft.phi  = extent.south;
        grinfo.upperright.lam = extent.east;
        grinfo.upperright.phi = extent.north;
    };

    {
        const auto gridSet = NS_PROJ::VerticalShiftGridSet::open(ctx, gridname);
        if( gridSet )
        {
            const auto& grids = gridSet->grids();
            if( !grids.empty() )
            {
                const auto& grid = grids.front();
                fillGridInfo(*grid, gridSet->format());
                return grinfo;
            }
        }
    }

    {
        const auto gridSet = NS_PROJ::HorizontalShiftGridSet::open(ctx, gridname);
        if( gridSet )