private void resetCache(final boolean detailed) {
        if (hasInfo() && nodesCache != null) {
            logInfo("NodesCache status before reset=" + nodesCache.formatStatus());
        }
        final long maxmem = routingContext.memoryclass * 1024L * 1024L; // in MB

        nodesCache = new NodesCache(routingContext.expctxWay, maxmem, nodesCache, detailed);
        islandNodePairs.clearTempPairs();
    }
find the elevation type for position
to determine the filter value

@param n  the point
@return  the filter value for 1sec / 3sec elevation source
main/src/main/java/cgeo/geocaching/brouter/core/RoutingEngine.java