Kidou Keisatsu Patlabor: On Television

Both of these shows revolve around using giant mech in an official capacity to protect the people. 

Very similar settings. Both are about daily life of Police officers and have a good balance of slice of life comedy and action. Very lighthearted and the only noticeable difference is that one has Mechs in it.  

These anime both depict characters with relatively mundane lives in extraordinary settings, and provide a counterpoint to other shows within their specific subgenres. Patlabor is to mecha as Planetes is to hard sci-fi. As a contrast to most other shows of these types which involve constant strife and warfare, these shows depict how humanity can live peacefully with advanced technology and noticeably put emphasis on human drama instead of epic battles, although both do eventually take more dramatic twists. 

Dominion and Patlabor share several elements, such as the theme of police employing unusual, by real life's standards, gear in the fight against crime. Both heroines, Noa and Leona, are newly joined crew members and are sisters from another mother, who are equally infatuated in their trusty, mechanical, steeds. Not to mention their tomboyish chara design, the two police officers really could have been siblings. As to the rest of the cast, Patlabor has a more grounded Police department, while the one depicted in Dominion is much more bombastic. In case of the Newport City Tank Police division, the "bomb" part should be treated literally on numerous occasions. The entire corps must be Oota's (another pilot from Patlabor) relatives, who are equally trigger-happy while handling high velocity explosive means of perpetuating the law and order. The biggest thematic difference (not including the featured machines) will be the amount of destruction. If you are looking for an anime that abides OSHA, then Patlabor will be great. If you'd like to watch the "Los Angeles from Terminator the anime", then Domion Police is your choice.  read more 

Shows have the same type humor, and similar main characters. both also from the early 90s  

A strong aspect of both anime is the dynamic between a machine, its operator and the team of mechanics that keep it running. There are a lot of similarities between the two with regards to how the characters surrounding the machine interact and how their relationships evolve while working together. Another thing these two anime share is a tendency to step away from the larger overarching storyline to focus in on the characters dealing with some slightly mundane problem. These episodes are great for character development and give a lot more depth to the worlds in which they're set. 

Both are mainly police and robot themed shows, with the occasional occult or bio monster showing up. While in different ways, both effectively cover the whole spectrum from dead serious to purely gag driven episodes. 

Nothing similar really, but there are mechatronic robots 

Active Raid is like an updated, funkier silly copy of Patlabor in many aspects. You'll probably find your self comparing not only the main plot but also many characters of these series if you watch them both. If you enjoy slice of life shows accompanied by mecha action and a bunch of mismatched eccentric characters you may enjoy Patlabor to the fullest.  

Both are action comedies that revolve around hapless divisions of the Tokyo Police department with plucky female officers as the leads. 

What brings these two vintage anime series together more than anything is how the series mixes comedic episodes with darker stories. Episodes can be cool or silly, which can be problematic if silly humour bore you. For most people, Lupin III and Mobile Police Patlabor will not be their first entry into both franchises. As such, the shift in tones will like be a shock when compared with their more popular movies. Luckily, you'll be prepared for that!  

The Patlabor and Ghost in the Shell series are engaging police procedural that are very different (less dark or philosophical) from their movie counterparts. Section 9 (in Ghost in the Shell) and Second Special Vehicles Division (in Patlabor) are specialized units in a society where criminals are using advanced technologies to commit crimes. Patlabor has mostly stand alone episodes with a wide variety of styles including comedic slice of life, action mecha, and thriller. Ghost in the Shell alternates between lighter self-contained episodes and more serious episodes from the overarching storyline. Patlabor is an overlooked anime compared to Ghost in the Shell. 

Although a decade separates their release, Patlabor and Master Keaton are adapted from manga created using the same mangaka ethics. They are character driven shows that avoids fast faced, action oriented techniques used in mecha or adventure anime/manga. They have no overarching plots, but instead tell simple and concise stories. Both series would have a hard time connecting with a modern (male) audience if they were widely available today. Yet, Patlabor and Master Keaton have their charms that makes them beloved by old-school anime watchers.