Between Colonial, Moslem, and Post-Independence Era, Which Layer of Urban Patterns should be Conserved?

Ancient maps reveal that Dutch colonial have covered alun-alun as the moslem city image like those in Jakarta, Surabaya, except in Semarang. Both Indonesian Moslem and colonial city experts cannot explain the phenomena. The alun-alun lama Semarang left its morphologic arthefac. Which layer of urban design should be conserved? To reveal the layer of the development, three dimensional picture by freehand modeling based on visual historical aprroach methode can be done as an early stage. The civilization era are in interaction, but tend to neglect the moslem city image. Further research is needed using a computer drawing, to get a clearly image of moslem city.