According to the story on page 18/447, Pra Ram Ratchaniwet Palace or Ban Puen Palace is a former Royal Palace located in Petchaburi Province. It was commissioned by King Chulalongkorn (Rama V) in order to serve as an alternative country residence to the, already existing, Royal Palace of Pra Nakhon Keeree (article 450 on the same page) siting on the hilltop whose area was becoming inconvenient and rather dangerous in rainy season.
The computer colored photo below shows the pavilion built over the foundation stone, the first stone of the construction of the Palace, waiting for King Rama V to begin the royal Brahmanism ritual before the construction continued.
Note: The white elephant flags, the old styled national flag used in the old days (related article on page 2/34)