PDF with all the constituency candidates. But what I cannot find was a map which shows the extend of the constituencies, the most obvious way to visualize them.
For this election, Samut Prakan is divided into seven constituencies. The population in each constituencies varies between 155,000 in constituency 6 and 195,000 in constituency 4. Like in all other provinces, constituency 1 covers the central parts, yet due to the high population only parts of the Mueang district. In fact, the district is divided into three constituencies. On the other hand, constituency five contains two complete districts, and two more subdistricts from two further districts.
The interesting part came when I added the constituency boundaries into the district map created by fellow Wikipedian hdamm. The subdistrict boundaries I used failed to make constituency two a single continuous area. As I recalled from an earlier Royal Gazette announcement on municipal constituencies, the originally announced constituencies had to be revoked since they did not form two continuous areas, so I was suspecting there was something wrong, maybe I had misread the subdistrict names and highlighted the wrong one, or more likely that the boundaries I used were flawed.
The area in question is the boundary between the subdistricts Theparak and Phraek Sa of Mueang district, which I found to be separated by Phraek Sa Mai subdistrict. To be sure that this boundary is correct, I checked the announcement on the creation of Phraek Sa Mai subdistrict from 1995. This really confirms, that the northern boundary of Phraek Sa Mai starts at the corner of Theparak and Bang Mueang, so Phraek Sa cannot have any boundary with Theparak.
Thus there are only two possible answers to this strange constituency boundary. Either, non-continuous constituencies are allowed in the current election laws for the nation-wide elections - but my Thai clearly isn't good enough to find and read the relevant law - or quite unlikely that the Election Commission has drawn invalid constituencies.