Changes

===US rectangular system===

===US rectangular system===

[[File:Drive-mechanisms-and-recovery_fig1.png|thumb|left|'''Figure 1.''' (a) official plat of township sectionized and numbered, with adjoining sections. (b) official plan of numbering congressional townships from meridians and baselines.]]

[[File:Land-description-and-maps fig1.png|thumb|'''Figure 1.''' (a) official plat of township sectionized and numbered, with adjoining sections. (b) official plan of numbering congressional townships from meridians and baselines.]]

The rectangular survey system ... sets up what is known as "initial points," a position which is determined by accurate field astronomical methods. From these ... points, lines known as principal meridians and base lines are extended. The principal meridian line runs north and south conforming to the true meridian and extending from the initial point or monument. Regular township corners are established at intervals of 480 chains ([[distance::6 miles]]) along this line.

The rectangular survey system ... sets up what is known as "initial points," a position which is determined by accurate field astronomical methods. From these ... points, lines known as principal meridians and base lines are extended. The principal meridian line runs north and south conforming to the true meridian and extending from the initial point or monument. Regular township corners are established at intervals of 480 chains ([[distance::6 miles]]) along this line.

[[File:Drive-mechanisms-and-recovery_fig2.png|thumb|'''Figure 2.''' An acre section and its subdivision into smaller components.]]

[[File:Land-description-and-maps fig2.png|thumb|'''Figure 2.''' An acre section and its subdivision into smaller components.]]

[[:Image:Drive-mechanisms-and-recovery_fig1.png|Figure 1]] is an example of a U.S. Congressional Township. A standard Congressional Township contains 36 sections with [[area::23,040 acres]] of land. Normally, sections (nos.) 16 and 36 were ... set aside ... for school purposes. [[:Image:Drive-mechanisms-and-recovery_fig2.png|Figure 2]] is an example of a [[area::640 acre]] section and how it is subdivided and described in smaller components.

[[:Image:Land-description-and-maps fig1.png|Figure 1]] is an example of a U.S. Congressional Township. A standard Congressional Township contains 36 sections with [[area::23,040 acres]] of land. Normally, sections (nos.) 16 and 36 were ... set aside ... for school purposes. [[:Image:Land-description-and-maps fig2.png|Figure 2]] is an example of a [[area::640 acre]] section and how it is subdivided and described in smaller components.

Due to the curvature of the earth, it is necessary to make corrections in the parallels and meridians... This is accomplished ... usually at intervals [of] 24 miles east and west of the principal meridians. This method produces the rectangular sections of [[area::640 acres]] each, with the sections along the north and west boundaries of the township absorbing the deficiency or excess in the measurements and convergence.

Due to the curvature of the earth, it is necessary to make corrections in the parallels and meridians... This is accomplished ... usually at intervals [of] 24 miles east and west of the principal meridians. This method produces the rectangular sections of [[area::640 acres]] each, with the sections along the north and west boundaries of the township absorbing the deficiency or excess in the measurements and convergence.