int lflat_index = (int) Math.floor(lat_index);
    public int interpElevationAt(float lat, float lon) {        if (frame_is_valid == true) {            if (lat >= dsi.sw_lat && lat <= dsi.ne_lat && lon >= dsi.sw_lon                    && lon <= dsi.ne_lon) {                // lat/lon_post_intervals are *10 too big -                // extra 0 in 36000 to counteract                float lat_index = (lat - dsi.sw_lat) * 36000F                        / uhl.lat_post_interval;                float lon_index = (lon - dsi.sw_lon) * 36000F                        / uhl.lon_post_interval;                int lflon_index = (int) Math.floor(lon_index);                int lclon_index = (int) Math.ceil(lon_index);                int lflat_index = (int) Math.floor(lat_index);                int lclat_index = (int) Math.ceil(lat_index);                if (elevations[lflon_index] == null)                    read_data_record(lflon_index);                if (elevations[lclon_index] == null)                    read_data_record(lclon_index);                //////////////////////////////////////////////////////                // Print out grid of 20x20 elevations with                // the "asked for" point being in the middle                //          System.out.println("***Elevation Map***");                //          for(int l = lclat_index + 5; l > lflat_index - 5;                // l--) {                //              System.out.println();                //              for(int k = lflon_index - 5; k < lclon_index + 5;                // k++) {                //                  if (elevations[k]==null) read_data_record(k);                //                  System.out.print(elevations[k][l] + " ");                //              }                //          }                //          System.out.println();System.out.println();                //////////////////////////////////////////////////////                int ul = elevations[lflon_index][lclat_index];                int ur = elevations[lclon_index][lclat_index];                int ll = elevations[lflon_index][lclat_index];                int lr = elevations[lclon_index][lclat_index];                float answer = resolve_four_points(ul,                        ur,                        lr,                        ll,                        lat_index,                        lon_index);                return Math.round(answer);            }        }        return -32767; // Considered a null elevation value    }