Aliquot Part Generator

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An aliquot part is an equal area subdivion that leaves no remainder area. In BLM cadastral survey and legal descriptions, only quarter or half divisions of a section of a township, are known as "aliquot parts". Aliquot parts themselves may also be subdivided into other aliquot parts ad infinitum.

The Aliquot Part Generator is a standalone web-page application that facilitates the visualization and description of BLM aliquot parts. The web page does not require an internet connection to function.

There are two major sections: the aliquot window on the left and the operations on the right. On the left side, there is a depiction of a standard 6 mile by 6 mile square township divided into 36 sections. As aliquot parts are generated and displayed, they will be shown in this window. On the right side, there are a number of operations that will affect the aliquot window.

Aliquot Window

The aliquot window depicts the 36 sections of a standard township. You use this window to select aliquot parts to see their description and to split or join them. As you use the operations on the right, the aliquot window will be divided into rectangles that represent idealized aliquot part subdivisions. At any time, you may start over with an empty section by reloading the page.

You make selections by left-clicking aliquot parts in the aliquot window. This will highlight the aliquot part in yellow and show the description in the text area to the right. You may select multiple aliquot parts simultaneously by holding down the 'Control' key while selecting parts. The 'Control' key will select or de-select aliquot parts without affecting the rest of your selection.

Build Menu

All operations, unless otherwise noted, affect all selected aliquot parts. At the top of the build menu, there is a button to allow you to quickly select all aliquot part divisions in the aliquot window. The rest of the build menu is broken into to parts: Subdivide and Join.


The three subdivide operations are described below. Subdividing an aliquot part will reset your selection and clear the Description section. You may not divide a part more than five times. If an operation is not allowed, its button will be disabled.


Divides the selected parts into four quarters. The number in the box to the right determines how many times to perform the quarter. If quartering more than once, all four resulting parts will be quartered again and so on.

N & S Half

Divides the selected parts into one north half and one south half.

E & W Half

Divides the selected parts into one east half and one west half.


Use this to join a number of aliquot parts back together, or to reset an entire section. If the currently selected parts can be joined, the first button will be enabled and the new aliquot part will be displayed as its label. Clicking the button will replace the selected parts with the part described in the label. The second button will always join the entire section it describes.

The only selections valid for joining aliquot parts are: exactly two quarters that form a valid aliquot half, exactly four quarters that form a larger aliquot quarter, or exactly two halves that form a larger quarter or half.


The text field is a display of the aliquot part description for the currently selected aliquot parts and will change as the selection changes. All aliquot part descriptions are organized as a comma delimited list by section, with the section identifier coming first. The list of descriptions is sorted in a counter clockwise fashion, starting with the north eastern quarter.

To quickly see aliquot parts from their descriptions, first type aliquot part descriptions into the text area, then click "Locate". Every section in the aliquot window will reset, even if it was not described. The aliquot window will automatically divide itself until all described aliquot parts can be properly displayed, and the described aliquot parts will be selected.

Overlapping parts are not supported and will not be divided if one is encountered. If this happens, any descriptions that were not shown in the aliquot window will be moved to the end and prepended with an asterisk (*), indicating that there was an error. The same thing will happen if any descriptions are in a format that cannot be understood.

The aliquot part must be written using one of the following formats:

Section identifiers must come first, and contain some separator before the aliquot part descriptions start:

Spaces are optional in all formats. If the section is omitted, it will default to Section 1.


Author: Jarad Bond, Data Management Section, BLM-Alaska
 Last Modified: 2012-03-28