Levelling Rise and Fall Method

Rise & Fall Method Levelling Calculator

Project Name Location

Starting BM RL

No	B.S	I.S	F.S	Rise	Fall	R.L	Remarks
1

Rise & Fall Method Levelling Calculator

This application is a browser-based tool used in surveying and civil engineering to compute Reduced Levels (R.L.) using the Rise & Fall method. It automates calculations, minimizes human error, and provides validation checks.

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1. Purpose of the Tool

The Rise & Fall method is used to determine elevation differences between points. This tool allows users to:

• Enter staff readings (B.S, I.S, F.S)
• Automatically calculate Rise and Fall
• Compute Reduced Levels (R.L.)
• Perform arithmetic checks
• Save and export level book data

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2. User Interface Structure

Input Fields

• Project Name
• Location
• Starting Benchmark RL

Table Columns

• B.S – Back Sight
• I.S – Intermediate Sight
• F.S – Fore Sight
• Rise
• Fall
• R.L – Reduced Level
• Remarks

The table dynamically grows using the Add Row button.

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3. Adding Rows

function addRow(){
 let t=document.getElementById("levelTable");
 let r=t.insertRow();
}

This function inserts a new row into the table and assigns:

• Row number
• Input fields for B.S, I.S, F.S
• Empty cells for calculated values

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4. Core Calculation Logic

Step 1: Initialization

let bm = parseFloat(document.getElementById("bm").value);
let prev = null, rl = bm;

• bm: Starting benchmark value
• rl: Current Reduced Level
• prev: Previous reading

Step 2: Loop Through Rows

Each row is processed sequentially.

rows.forEach((row,i)=>{
 let rd = parseFloat(bs||isv||fs);
});

The reading (rd) is taken from whichever value exists among B.S, I.S, or F.S.

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5. Rise & Fall Calculation

Rise Condition

if(prev > rd){
 rise = prev - rd;
 rl += rise;
}

Fall Condition

else{
 fall = rd - prev;
 rl -= fall;
}

Logic:

• If current reading is less → Rise
• If current reading is more → Fall

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6. Reduced Level (R.L) Calculation

The Reduced Level is updated continuously:

row.cells[6].innerText = rl.toFixed(3);

• Rise increases RL
• Fall decreases RL

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7. Arithmetic Check

The tool performs standard levelling checks:

ΣBS - ΣFS = ΣRise - ΣFall = Last RL - First RL

Displayed using:

document.getElementById("check").innerHTML =
"Check: ΣBS-ΣFS=" + ...

This ensures calculation accuracy.

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8. Change Point (C.P) Detection

A Change Point is automatically detected when:

• A row has F.S
• Next row has B.S

if(rows[i].cells[3].value && rows[i+1].cells[1].value)

Such rows are marked:

• Remark = "C.P"
• Highlighted visually

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9. Data Storage (Local Storage)

Saving Data

localStorage.setItem("levelBook", JSON.stringify(data));

Stored data includes:

• Project name
• Location
• Benchmark RL
• All table rows

Auto Load

When the page loads:

window.onload = function(){
 let d = localStorage.getItem("levelBook");
}

Saved data is restored automatically.

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10. Export & Import

Export JSON

• Creates a downloadable JSON file
• Useful for backup or sharing

Import JSON

• Reads uploaded JSON file
• Restores saved data
• Reloads application

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11. Clear Function

function clearAll(){
 localStorage.removeItem("levelBook");
 location.reload();
}

This resets the entire dataset after confirmation.

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12. Key Engineering Advantages

• Eliminates manual calculation errors
• Instant validation of results
• Supports field data recording
• Portable and offline-capable
• Easy data backup and sharing