Rise and fall method
The rise and fall method is a technique used in surveying to determine the difference in elevation between two points. It is commonly used in design and construction to create accurate site plans.
A levelling instrument such as a dumpy level or a theodolite is set up at one point (the benchmark) and a staff is placed at a point whose elevation is to be determined. The instrument is then sighted on the staff and the vertical distance between the instrument and the staff is measured. This is known as the backsight.
The staff is then moved to the next point and the instrument is sighted on the staff again. The vertical distance between the instrument and the staff is measured once more, and this is known as the foresight.
If the foresight is higher than the backsight, it means that the point being surveyed is higher than the benchmark. The difference between the foresight and the backsight is known as the rise. If the foresight is lower than the backsight, it means that the point being surveyed is lower than the benchmark. The difference between the backsight and the foresight is known as the fall.
The process is repeated for multiple points, with the rise and fall measurements being added and subtracted as appropriate.
[edit] Related articles on Designing Buildings
Featured articles and news
Government responds to the final Grenfell Inquiry report
A with a brief summary with reactions to their response.
A brief description and background to this new February law.
Everything you need to know about building conservation and the historic environment.
NFCC publishes Industry White Paper on Remediation
Calling for a coordinated approach and cross-departmental Construction Skills Strategy to manage workforce development.
'who blames whom and for what, and there are three reasons for doing that: legal , cultural and moral"
How the Home Energy Model will be different from SAP
Comparing different building energy models.
Mapping approaches for standardisation.
UK Construction contract spending up at the start of 2025
New construction orders increase by 69 percent on December.
Preparing for the future: how specifiers can lead the way
As the construction industry prepares for the updated home and building efficiency standards.
Embodied Carbon in the Built Environment
A practical guide for built environment professionals.
Updating the minimum energy efficiency standards
Background and key points to the current consultation.
Heritage building skills and live-site training.
Shortage of high-quality data threatening the AI boom
And other fundamental issues highlighted by the Open Data Institute.
Data centres top the list of growth opportunities
In robust, yet heterogenous world BACS market.
Increased funding for BSR announced
Within plans for next generation of new towns.
Comments
[edit] To make a comment about this article, or to suggest changes, click 'Add a comment' above. Separate your comments from any existing comments by inserting a horizontal line.