No matter what, the importance of a map was undoubted. When you needed it but couldn't get it, you would know how inconvenient it was.
If it was in the era of technology, it would be very easy to obtain a map. Whether it was a city or a place, or even a map of the entire planet, it could be easily obtained.
If it involved confidential information, the map might not show it, unless it was a special map.
The advantage of technological advancement was that many expensive things had gradually become cheap. Even ordinary people were qualified to enjoy them.
However, in this world, it was not easy to obtain a map. One had to go to a special location, and at the same time, they had to bear huge risks.
For example, there were maps of the government's Yamen and military camps. Moreover, Tang Zhen had indeed obtained some gains before this.