JIM-GEM English Area Grid, 9” x 12”
Use to determine the area of any flat surface in English measurement units. Scales and ratios include the following:
1 in.: 1 in
1 in.: 1 ft.
1 in.: 1 yd.
1 in.: 500 ft. = 10.56 ins.: mi. = 1:6,000
1 in.: 1,000 ft. = 5.28 ins.: mi. = 1:12,000
1 in.: 1,320 ft. = 4.0 ins.: mi. = 1:15,840
1 in.: 1,667 ft. = 3.167 ins.: mi. = 1:20,000
1 in.: 2,000 ft. = 2.64 ins.: mi. = 1:24,000
1 in.: 3,334 ft. = 1.58 ins.: mi. = 1:40,000
1 in.: 5,280 ft. = 1 in.: mi. = 1:63,360
Two edge scales (inches to tenths and inches to 16ths) are included. It may also be used with any other map scale, but first you must figure the conversion factor. Available in standard size or super size.
How To Use the English Area Grid – To use, randomly place grid over area to be computed and count the dots falling within that area. Count every other dot that falls on the boundary of the area. Multiply the number of dots counted by the proper conversion factor for the scale you are using to obtain total area.
Example: Using a map scale of 1”= 1,320 ft.
1,320² = 1,742,400 sq. ft./sq. in. of area grid
1,742,400 ÷ 43,560 sq. ft. per acre = 40 acres/sq. in. of area grid
40 acres ÷ 64 dots per sq. in. of area grid = 0.625 acres per dot conversion factor
Each dot represents 0.625 acres. If the dot total of an area is 50 dots, multiply 50 by the conversion factor. 50 x 0.625 = 31.25 acres within area.
This can be done using any map scale.
