The math behind SketchAndCalc is called the shoelace formula or shoelace algorithm. It also goes by the name of Gauss’s area formula and the surveyor’s formula.
SketchAndCalc is currently being trusted every day in fields from neuroscience and nano-computing to landscape gardening and farming. If you have reason to believe that SketchAndCalc’s calculation of area is inaccurate, please verify that your imported image is true and that it’s X Y ratio is 1:1 as this is a common mistake.
When finding the area of a map the drawing scale is set automatically based on map data. Just zoom in and start drawing.
To set the scale of an image you’ll be prompted to draw and enter a ‘known length’ during image importation. A ‘known length’ could be any landmark or object on the image you know the length of. It could be a pin head, rular, or doorway.
If you happen to know the scale you need before drawing you can manually set the length of a grid square in the measurement system you chose from the top right corner.
Not only can you draw multiple line lengths on separate layers, you can sum the total length of all open shapes together in one place. Giving you a total view of all liner lengths on all layers.
You can even reference one layer whilst drawing another, and color code them.
Area and perimeter results are offered in both metric (decimal measurement system or SI) and the imperial measurement system.
You can import images in the following formats:
.PNG .GIF .JPG .PDF .SVG .DXF .DWG
There are desktop apps for Windows, and macOS. Plus mobile apps for iOS and Android tablets and phones.
Detailed help articles and in-depth tutorials with animations can be found here.
In addition, there are many blog articles that discuss use-cases.
If you’re not able to find answers to your question please drop us a note with a detailed description or question and we’ll get right back to you. The more info the better.
There are two Subscription options and a Pay-As-You-Go plan for infrequent use.
Based on usage you can choose from the following:
Project – a monthly recurring subscription.
Pro – an annual recurring subscription.
Pay-As-You-Go – a daily 24-hour subscription that is billed monthly *
* You are only billed for the day/s use during the course of a month.
To view our pricing in your currency click here.
There are three team plans that allow an account to be shared across your team.
Based on the size of your team choose from the following:
Pro Team 5 – five team members can access the account simultaneously.
Pro Team 20 – twenty team members can access the account simultaneously.
Pro Unlimited – an unlimited number of team members can access the account simultaneously.
We’ll send you a reminder 7 days before your annual plan renews. Cancel your subscription easily at any time.
With Pay-As-You-Go there are no monthly subscription payments. You pay only for the day or days you use SketchAndCalc during the course of a single month.
Example in USD: (For prices in your local currency click here.)
Sign up on Sept 3rd, and use for a single day (24 hours). You should expect to be billed 2.49 USD on or near Oct 3rd (approximately 1 month later).
If you subsequently log in and agree to use SketchAndCalc on Nov 14th and 15th you should expect to be billed 4.98 USD on or near December 3rd.
The Project plan is our month-to-month unlimited subscription. You can log in and use SketchAndCalc anytime for a flat fee of 11.99 USD per month.
Example in USD:
Sign up to the Project plan on July 16th. You should expect to be billed 11.99 USD on or near the 16th of each month thereafter.
The Pro plan is our annual unlimited subscription. You can log in and use SketchAndCalc anytime for a flat fee of 99 USD per year.
Example in USD: (For prices in your local currency click here.)
Sign up to the Pro plan on Jan 2nd, 2019. You should expect to be billed 99 USD on Jan 2nd of each year thereafter.
You can cancel your subscription at any time.
Cancel anytime. Simply login and go to Settings > Account > Unsubscribe.
Upon canceling your annual subscription the balance of the plan will be prorated monthly, based on the date of cancellation. A refund for the remaining months will be offered and credited to the card on file.
Refunds for the balance of monthly or daily subscriptions will not be offered. In this case, the billing cycle will simply stop and no further payments will be processed.
Our Free Educator Account has access to a dashboard where log-in sessions can be created for students and their saved files can be managed.
A session name and generated password can be made available to all students who, upon log-in, will have full access with the exception of being able to delete files.
Registration is limited to educators of accredited schools only and subject to a verification process that involves adding a SketchAndCalc ‘badge’ to the schools website.
This badge is required to verify that an educator is a current faculty member of an accredited school.
During registration an educator will nominate a page of the school website (example: www.school-homepage.edu/page1) as the intended location of the badge so that it can be easily found by our servers.
An email, containing a selection of badges will then be sent with instructions.
It will normally take 24 hours to validate an account as this is a manual process. Once registration has been approved and the badge has been correctly placed (in Wordpress, for example, it gets added as a custom html not embed), the educator will be able to log-in to the dashboard (Note: educators do not select ‘student’ at the log-in screen).
Log-in sessions created from the dashboard last 12 hours but can be ended at anytime. Simply enter a session name, and click ‘Start Session’ to generate a random password that, along with the session name, can be distributed to all students.
To log-in, students select the ‘student’ toggle switch on the log-in screen and enter the session name and password provided.
Students can export, print, and save files made during sessions. Educators can also view all saved files made during each session from the dashboard.
Drawing settings are controlled globally by the educator from the dashboard.
Should an educator leave the profession, or move to another school, the account can be closed. Closing the account converts it to a regular user account, requiring a subscription, and or re-registration to a new school.
To begin click Sign up and select the ‘Educator’ switch.
Should you have any questions please reach out here.