If you are looking for the ancient map of Yangon (Rangoon) during the colonial period, either for the research or academic purpose, or just for curiosity, here is the map of Yangon (Rangoon) in 1912. You can see that colonial Rangoon was quite small compared to current day Yangon. Nevertheless, the city plan remains essentially the same today as 100 years ago. The downtown area plan of current day Rangoon obviously was already in place in 1912 according to this map.