lwproj_from_PJ()

LWPROJ* lwproj_from_PJ	(	PJ *	pj,
		int8_t	extra_geography_data
	)

Allocate a new LWPROJ containing the reference to the PROJ's PJ If extra_geography_data is true, it will generate the following values for the source srs: is_latlong (geometric or not) and spheroid values.

Definition at line 325 of file liblwgeom/lwgeom_transform.c.

{
        PJ *pj_source_crs = proj_get_source_crs(NULL, pj);
        uint8_t source_is_latlong = LW_FALSE;
        double out_semi_major_metre = DBL_MAX, out_semi_minor_metre = DBL_MAX;
 
        if (!pj_source_crs)
        {
                lwerror("%s: unable to access source crs", __func__);
                return NULL;
        }
        uint8_t source_swapped = proj_crs_is_swapped(pj_source_crs);
 
        /* We only care about the extra values if there is no transformation */
        if (!extra_geography_data)
        {
                proj_destroy(pj_source_crs);
        }
        else
        {
                PJ *pj_ellps;
                double out_inv_flattening;
                int out_is_semi_minor_computed;
 
                PJ_TYPE pj_type = proj_get_type(pj_source_crs);
                if (pj_type == PJ_TYPE_UNKNOWN)
                {
                        proj_destroy(pj_source_crs);
                        lwerror("%s: unable to access source crs type", __func__);
                        return NULL;
                }
                source_is_latlong = (pj_type == PJ_TYPE_GEOGRAPHIC_2D_CRS) || (pj_type == PJ_TYPE_GEOGRAPHIC_3D_CRS);
 
                pj_ellps = proj_get_ellipsoid(NULL, pj_source_crs);
                proj_destroy(pj_source_crs);
                if (!pj_ellps)
                {
                        lwerror("%s: unable to access source crs ellipsoid", __func__);
                        return NULL;
                }
                if (!proj_ellipsoid_get_parameters(NULL,
                                                   pj_ellps,
                                                   &out_semi_major_metre,
                                                   &out_semi_minor_metre,
                                                   &out_is_semi_minor_computed,
                                                   &out_inv_flattening))
                {
                        proj_destroy(pj_ellps);
                        lwerror("%s: unable to access source crs ellipsoid parameters", __func__);
                        return NULL;
                }
                proj_destroy(pj_ellps);
        }
 
        PJ *pj_target_crs = proj_get_target_crs(NULL, pj);
        if (!pj_target_crs)
        {
                lwerror("%s: unable to access target crs", __func__);
                return NULL;
        }
        uint8_t target_swapped = proj_crs_is_swapped(pj_target_crs);
        proj_destroy(pj_target_crs);
 
        LWPROJ *lp = lwalloc(sizeof(LWPROJ));
        lp->pj = pj;
        lp->source_swapped = source_swapped;
        lp->target_swapped = target_swapped;
        lp->source_is_latlong = source_is_latlong;
        lp->source_semi_major_metre = out_semi_major_metre;
        lp->source_semi_minor_metre = out_semi_minor_metre;
 
        return lp;
}

References LW_FALSE, lwalloc(), lwerror(), LWPROJ::pj, proj_crs_is_swapped(), LWPROJ::source_is_latlong, LWPROJ::source_semi_major_metre, LWPROJ::source_semi_minor_metre, LWPROJ::source_swapped, and LWPROJ::target_swapped.

Referenced by gml_reproject_pa(), and lwgeom_transform_from_str().

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