I think you will find this link helpful: http://www.pokemongodb.net/2016/04/pokemon-go-types.html

It has a chart at the top showing what percentage of Kanto pokemon belong in each type. Below, it shows a list of all Pokemon in the game and after that there is a chart showing what type of Pokemon to expect in various Biomes.

Happy Hunting!

Possible Types

Normal

Boundaries, Landuse, Places, Roads, Transit, College, Commercial, Common, Footway, Hospital, Hotel, Library, Major Road, Minor Road, Pedestrian, Pitch, Playa, Recreation Area, Retail, Runway, School, Sports Center, Stadium, University

Grass

Landmass, Farm, Farmland, Farmyard, Forest, Garden, Golf Course, Grass, Meadow, Nature Reserve, Park, Path, Playground, Residential, Wood

Bug

Farm, Farmland, Farmyard, Forest, Garden, Golf Course, Grass, Nature Reserve, Park, Path, Playground, Wood

Water

Water, Basin, Canal, Dock, Drain, Glacier, Lake, Ocean, Reservoir, River, Riverbank, Stream

Flying

Farm, Farmland, Farmyard, Forest, Garden, Grass, Nature Reserve, Park, Wood

Rock

Building, Landmass, Highway, Industrial, Parking, Quarry, Railway, Urban Area

Ground

Landmass, Ditch, Land, Parking, Playground, Railway, Taxiway, Urban Area

Fairy

POIs, Cemetery, Place of Worship

Dark

Cemetery, Cinema, Theatre

Steel

Building, Railway

Dragon

POIs

Ghost

Cemetery

Ice

Glacier

Psychic

Hospital?

Electric

Industrial

Fire

Residential?

Poison

Wetland

Are there any other ghost types in Gen 1 besides the Gastly family? Anyways, I've found a few in urban locations and a few in suburbs. I have also heard that they are more common at night. I can't say for sure because I've largely been hunting in the evenings so my 'data' would be biased.

The only current ghost type Pokémon are from generation 1 (the Gastly family - Gastly, Haunter, and Gengar). These can be caught at any time of day, although they are more likely to appear at night. I am not aware of any location restrictions for Ghost-type Pokémon at this time. Thanks to user Ellesedil for pointing this out with evidence of daytime appearance here.

Furthermore, there is no hard evidence that Gastlys (or other Pokémon) appear more often at night. Several sources (such as Polygon's guide) claim that Gastly spawns more frequently at night, but don't offer any source or evidence, so take this how you will. Personally I have seen two Gastlys at night and two during the early afternoon, so it is entirely possible that any night time relation is false.

Edit: After the edit to the question, my response is that there is no such delineation as "Purple Type" and that Psychic and Ghost are different types and have different spawning/location-time rules.

For Poison:

I've know 2 locations at my town that have a ton of Nidoran spawns.
Zubat apparently spawns everywhere, day or night.

For Psychic:

I know 1 location which spawns a lot of Abras, another location that spawns a lot of Drowzees. Also caught a random Jynx at one point. Drowzee is more an urban area while Abra is more grassland.

For Ghost:

I cannot say for sure, I've seen Ghastly in all places I went to, its just super rare. Also I've noticed that Ghastly shows up around 2x-3x at night.