This program can be used to measure the area of a closed curve on the computer screen. It operates in two modes, planimeter mode and polygon mode.
In planimeter mode, the program can measure the area of any closed curve.
The algorithm used is based upon Green's Theorem.
See the section on Area calculation.
In polygon mode, it can measure the area of a simple polygon using the Shoelace Algorithm.
To measure the area of a closed curve, drag the tracer cross onto the curve, double-click the counter to reset it, then drag the cross once around the curve. The counter gives the area enclosed by the track of the tracer cross. The area is given in units which depend upon the setting of the Scale Menu.
Use the shift and alt keys to limit tracking movement to horizonal and vertical movement respectively.
To measure the length of a path, instead of an area, hold down the alt-key while resetting the counter.
The length in given in units which depend upon the setting of the Scale Menu.
To measure the area enclosed by a polygon, double-click the counter to reset it, then drag the tracer cross onto each vertex in turn - vertex coordinates are recorded on mouseup. The counter gives the area enclosed by the polygon in units which depend upon the setting of the Scale Menu.
To measure the length of the perimeter, instead of the area, hold down the alt-key while resetting the counter.
The length in given in units which depend upon the setting of the Scale Menu.
The Planimeter and Polygon Web Widget is Copyright © 2011-2019 Harry Whitfield (G6AUC).
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA