rats

a.k.a. Ruby Alberta Township System

A ruby class to help with using the Alberta Township System. This class will allow you to create and represent townships, sections and quarter sections.

Status

This gem is not under active development, but is still maintained.

ATS

Alberta Township system is a land survey grid used in Alberta, Canada that divides the whole province into addressable locations.

A typical location looks like: NE 1-2-3 W4

Which can be broken down as follows ...

Meridian

from above example: [= W4] or West of the 4th Meridian

The Meridian is a constant line running perpendicular to the line of longitude, and increments approx. every 4th line of longitude, from East to West.

Alberta contains 3 of these Meridians, W4 through W6.

Range

a.k.a Range Lines

from above example: [= 3]

The Range is the x-axis within the given Meridian. It increases East to West and resets at the next Meridian. Each increase is approx. every 6 miles.

NOTE: The longitude lines are closer together the further North you get, so as you go North, there is less Ranges from East to West.

Township

a.k.a. Township Lines

from above example: [= 2]

The Township is the y-axis within the Meridian. It increases South to North and never resets, running from the Alberta-US border to the Northern border of Alberta. Each increase is approx. every 6 miles.

NOTE: The 6x6 mile "square" indicated by the Township (line) + Range (line) + Meridian is confusingly called a Township. So you have the Township line and the 6x6 mile Township "square".

Section

from above example: [= 1]

The Section represents a 1x1 mile "square" within the 6x6 mile Township. There can be up to a maximum of 36 Sections in a township. The number starts with 1 in the South-East corner and travels West to number 6. It then increases to 7 North of number 6 and counts up West-to-East until the number 12. It snakes back and forth until it finishes at number 36 in the North-East corner.

Multi

a.k.a. Multi Quarters

from above example: [= N or = North]

The Half Section represents a 1/2 x 1 mile area within the 1x1 mile Section. They are identified by "N", "E", "S" and "W".

from above example: [= NSE]

The Multi Quarter Section represents a 1/2 x 1 mile + 1/2 x 1/2 mile area within the 1x1 mile Section (or basically 3 of the 4 quarters). They are identified by "NSE", "NSW", "ENW", "ESW", "SNE", "SNW", "WNE" and "WSE", "NWS", "NES", "SEN", "SWN", "NWE", "NEW", "SEW", "SWE".

Quarter

a.k.a. Quarter Section

from above example: [= NE]

The Quarter represents a 1/2 x 1/2 mile square within the 1x1 mile Section. There can be 4 Quarters in a Section. They are identified by "NE", "NW", "SE" and "SW".

Purpose

The purpose of Rats is to make it easier to deal with location described using the Alberta Township System, at the Quarter, Section or Township level.

Validation

Included is validations, only allowing you to describe locations that actually exist.

For example, Range-line 30 is valid for Township-lines 1-18, but not 18-126.

NOTE: At the moment, invalid quarters within valid sections are not currently identified.

Parsing

Included is string parsing, allowing you to extract and separate the different fields from multiple string representations of the location.

For example, NE 1-2-3 W4 and 40300201NE are both recognized and parsed, representing the same location.

Expansion/Division

Townships, Sections and Half Sections can be divided into multiple Quarter Sections. 1 Half Section = 2 Quarter Sections 1 Multi Quarter Section = 2-3 Quarter Sections 1 Section = 4 Quarter Sections 1 Township = 144 Quarter Sections

For example, the Half Section N 1-2-3 W4 has the Quarter Sections NE 1-2-3 W4 and NW 1-2-3 W4.

Display

Included is string creation that can create common representations of the location.

Usage

Parse a location

quarter_section = Rats.new("NE 1-2-3 W4")

Print the location

quarter_section.location
quarter_section.location(:padded)
quarter_section.location(:short)
quarter_section.location(:long)

Read the attributes

quarter_section.quarter
quarter_section.section
quarter_section.township
quarter_section.range
quarter_section.meridian

Divide into multiple Quarter Sections

half_section = Rats.new("N 1-2-3 W4")
half_section.is_divisible?
quarter_sections = half_section.divide
# quarter_sections == [Rats.new("NE 1-2-3 W4"), Rats.new("NW 1-2-3 W4")]

multi_section = Rats.new("NSE 1-2-3 W4")
multi_section.is_divisible?
quarter_sections = multi_section.divide
# quarter_sections == [Rats.new("NE 1-2-3 W4"), Rats.new("NW 1-2-3 W4"), Rats.new("SE 1-2-3 W4")]

Information

links

http://en.wikipedia.org/wiki/Alberta_Township_System

Road Map

Future:

either correct the assumption that all quarters are valid in a valid section, or remove validation completely (re: all or none)
add support for Saskatchewan (no timeline, need to find data)

Assumptions

As currently written, I assume that within every valid section, all four quarters are valid. I know this to be incorrect, but I can not correct this until I know which cases this assumption breaks down.

Contributing

Fork it
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create new Pull Request