A length measuring device and a length measuring system are provided, in which the length measuring device includes a casing, a first rotating portion accommodated in the casing, and rotated with a portion of a circumference thereof being exposed out of the casing and in contact with an object to be measured, a first sensing portion which senses an amount of rotation of the first rotating portion, and a controller which converts the amount of rotation of the first rotating portion into length measurement. Additionally, the length measuring device may further include a second rotating portion coiled with a strip by a plurality of times, and rotated according to the strip being withdrawn or retracted through an outlet formed in the casing, and a second sensing portion which senses an amount of rotation of the second rotating portion, in which the controller may convert the amount of rotation of the second rotating portion into length measurement.

A tape measure including an elongate tape blade is shown. The tape measure includes a relatively short protective polymer film coupled to an end of the tape blade adjacent to the hook end of the tape blade.

A boundary marking device for defining boundaries of an athletic field on a ground surface includes a housing having an interior space. A slit extends through the housing into the interior space. A spool is coupled to the housing within the interior space. A tape is coiled around the spool and extends through the slit. The spool is rotatable in a first direction to uncoil the tape from the spool for extension of the tape from the housing and is rotatable in a second direction to coil the tape around the spool for retraction of the tape into the housing. A housing stake extends downwardly from the housing. The housing stake has a housing stake pointed end that is insertable into the ground surface to secure the housing to the ground surface. A peg has a peg pointed end that is designed to secure the tape to the ground surface.