proj_crs_is_swapped()

static uint8_t proj_crs_is_swapped ( const PJ *  pj_crs )

static

Definition at line 270 of file liblwgeom/lwgeom_transform.c.

{
    int axis_count;
    PJ *pj_cs = proj_cs_get_simplecs(pj_crs);
    if (!pj_cs)
        lwerror("%s: proj_cs_get_simplecs returned NULL", __func__);
 
    axis_count = proj_cs_get_axis_count(NULL, pj_cs);
    if (axis_count >= 2)
    {
        const char *out_name1, *out_abbrev1, *out_direction1;
        const char *out_name2, *out_abbrev2, *out_direction2;
        /* Read first axis */
        proj_cs_get_axis_info(NULL,
            pj_cs, 0,
            &out_name1, &out_abbrev1, &out_direction1,
            NULL, NULL, NULL, NULL);
        /* Read second axis */
        proj_cs_get_axis_info(NULL,
            pj_cs, 1,
            &out_name2, &out_abbrev2, &out_direction2,
            NULL, NULL, NULL, NULL);
 
        proj_destroy(pj_cs);
 
        /* Directions agree, this is a northing/easting CRS, so reverse it */
        if(out_direction1 && STR_IEQUALS(out_direction1, "north") &&
           out_direction2 && STR_IEQUALS(out_direction2, "east") )
        {
            return LW_TRUE;
        }
 
        /* Oddball case? Both axes north / both axes south, swap */
        if(out_direction1 && out_direction2 &&
           ((STR_IEQUALS(out_direction1, "north") && STR_IEQUALS(out_direction2, "north")) ||
            (STR_IEQUALS(out_direction1, "south") && STR_IEQUALS(out_direction2, "south"))) &&
           out_name1 && STR_ISTARTS(out_name1, "northing")  &&
           out_name2 && STR_ISTARTS(out_name2, "easting"))
        {
            return LW_TRUE;
        }
 
        /* Any lat/lon system with Lat in first axis gets swapped */
        if (STR_ISTARTS(out_abbrev1, "Lat"))
            return LW_TRUE;
 
        return LW_FALSE;
    }
 
    /* Failed the axis count test, leave quietly */
    proj_destroy(pj_cs);
    return LW_FALSE;
}

References LW_FALSE, LW_TRUE, lwerror(), proj_cs_get_simplecs(), STR_IEQUALS, and STR_ISTARTS.

Referenced by lwproj_from_PJ().

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