2026 Update: Now it supports all DJI Drone model SRT. (You can directly use tool in within this page also

Drone Chainage & SRT Processing

A Streamlit application that automates extraction and processing of GPS metadata from DJI drone video .srt files, generates chainage markers along a reference alignment (KML), and produces synchronized SRT outputs and 3D visualizations.

Purpose

• Extract latitude, longitude, altitude, and timestamp data embedded in DJI .srt files.
• Chainage: compute distances along a surveyed alignment (a 2D KML LineString) and insert regular markers (every 50 m).
• Project drone track start/end onto the chainage alignment to find matching station values.
• Visualize the drone path and alignment in an interactive 3D view.
• Export:
  • 3D KMLs of the drone route with START/END placemarks.
  • Six separate SRT files (Latitude, Longitude, Altitude, Timer, LatLon, Chainage).
  • Bulk‐processing support for multiple .srt files in one go.

Features & Workflow

1. Upload Inputs
   • DJI .srt (with [latitude: …], [longitude: …], [altitude: …]).
   • Full‐chainage .kml (2D LineString of reference alignment).
2. Generate 50 m Markers
   • Interpolate along the KML every 0.05 km.
   • Download markers_50m.kml for inspection.
3. Confirm Markers Direction
   • If backward, reverse the alignment and regenerate markers.
4. Project SRT Start/End
   • Parse the initial .srt into GPS track points.
   • Compute total route length.
   • Find nearest chainage-station for the first/last points.
5. Confirm SRT Direction
   • Reverse the track if start/end mapping is inverted.
6. Visualize in 3D
   • Chainage line (gray) at altitude = 0.
   • Drone track (red) in true altitude.
   • START (green) and END (blue) markers with station labels.
7. Export Initial SRT-Derived Files
   • Download initial_srt_route.kml with START/END.
   • Download a ZIP of six SRT files prefixed initial_01_…–initial_06_….
8. Bulk Processing (optional)
   • Upload multiple additional .srt files.
   • Skip Steps 2–6 and generate 3D KML + SRT ZIP for each.
9. Bundle & Download
   • All KMLs and SRTs are packaged into a final all_outputs.zip for one-click retrieval.

Under the Hood: Mathematical Background

1. Haversine Formula

Computes great‐circle distance between two GPS points (φ1,λ1) and (φ2,λ2):

Δφ=φ2−φ1,Δλ=λ2−λ1,a=sin2⁡(Δφ/2)+cos⁡φ1,cos⁡φ2,sin2⁡(Δλ/2),d=2Rarcsin⁡(a),

where:

• φ = latitude (radians), λ = longitude (radians)
• R ≈ 6371 km (Earth’s radius)
• d = distance along Earth’s surface.

2. Cumulative Chainage

Given points P0,P1,…,Pn:

Ck=∑i=1kd(Pi−1,Pi),

where d() is the segment length from Haversine.

3. Regular Interval Markers

To place markers every Δ km:

1. Build cumulative array [C0=0,C1,…,Cn].
2. For each$ D=0, Δ, 2Δ,…,C_n$: find segment i with Ci−1<D≤Ci, compute fraction f=(D−Ci−1)/(Ci−Ci−1), and interpolated point P(D)=(1−f)Pi−1+fPi.

The post Tool For – Making of Chainage Marked Drone Videos (2026 Updated) first appeared on BGol.

Learn how to turn your corridor drone videos into powerful tools with chainage labels.
Topics Covered:
Drone camera angle & flight plan tips
SRT telemetry from drones
Chainage calculation using GPS logs – Free Script & Tool
Overlaying chainage text on video – Video Editing Tips

DRONE SRT to CHAINAGE AND OTHER SRT COVERTER TOOL :
https://bgol.in/2025/09/20/tool-chainage-marked-drone-videos/

Other Links:
⦿ Math – Haversine Formula: https://en.wikipedia.org/wiki/Haversine_formula
⦿ Flight Visualizer: https://djitelemetryoverlay.com/srt-viewer/
⦿ Camera Telemetry Creator: https://goprotelemetryextractor.com/drone-heads-up-display
⦿ Video Editing Tool: https://filmora.wondershare.net/
⦿ Google Earth: https://www.google.com/intl/en_in/earth/about/versions/
⦿ Dronelink: https://www.dronelink.com/

Connect with me: https://www.linkedin.com/in/thevijayparmar/

Join BGol Community: https://bgol.in/register

The post Drone Chainage Video Making – BGol Webinar first appeared on BGol.

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Right‑Angle Triangle Field Calculator

A practical offline field tool for surveyors and engineers to quickly compute the third side of a right‑angled triangle.
Ideal for marking right angles in the field using methods like 3‑4‑5 triangle or for custom dimensions.

Features

Triangle Computation

• Enter any two sides → the tool computes the third side automatically.
• Calculates all triangle properties:
• Base (a)
• Height (b)
• Hypotenuse (c)
• ∠ at base (θ), ∠ at height (φ), Right angle (90°).
• Uses Pythagoras theorem in real time.

Interactive Visualization

• Live triangle sketch updates with each input.
• Computed side highlighted in sky‑blue glow.
• Displays side lengths and angles directly on sketch.
• Draws right‑angle marker at corner.

UI & Usability

• Dark/Light theme toggle (remembers preference).
• Error detection for invalid inputs (e.g., hypotenuse shorter than legs).
• Input highlighting:
• Recently entered values = green highlight.
• Auto‑computed side = blue highlight.
• Animated “ sparks” effect on computed side for visibility.

Formula & Explanation

• Shows formula, substitution, calculation, and result for transparency.
• Example:

  Formula: c² = a² + b²
  Substitution: c² = 6² + 8²
  Calculation: √(36 + 64)
  Result: c = 10

Preview

How to Use

1. Open Triangle Sides Calculator.html in your browser.
2. Enter any two dimensions (Base, Height, or Hypotenuse).
3. The third side and internal angles are computed instantly.
4. Review the live triangle sketch + step‑by‑step formula.

Example Use Case

• Field marking of right angles:
• Input Base = 9, Height = 12.
• Tool computes Hypotenuse = 15.
• Angles displayed: θ ≈ 53.13°, φ ≈ 36.87°.

Why Use This Tool?

• Saves time in the field — no manual calculator needed.
• Perfect for setting out right angles in construction and surveying.
• Runs fully offline in any browser (desktop or mobile).
• Provides visual + formula verification for confidence.

The post 🔺 Triangle Sides Calculator first appeared on BGol.

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How to Use?

Total Station Accuracy Visualizer

A modern offline web tool to visualize and compare the angular accuracy vs. linear error of different Total Stations and a Theodolite.
Ideal for surveyors and engineers when deciding what instrument suits their project requirements.

Features

Supported Instruments

• High-Precision Total Station (0.5″ accuracy)
• Standard Total Station (1″ accuracy)
• General-Purpose Total Station (2″ accuracy)
• Basic Total Station (5″ accuracy)
• Theodolite (20″ accuracy)

Accuracy Visualization

• Angular Accuracy Chart → Wedge visualization of angular spread.
• Linear Error Chart → Bar chart showing error in mm at selected distance.
• Adjustable distance slider (1–5000 m) to see how error grows with range.

Built-in Calculations

• Formula: Linear Error (mm) = Distance(m) × tan(θ) × 1000
• Displays step-by-step math for each instrument (θ conversion from arcseconds).

UI & Experience

• Dark/Light Mode toggle.
• Station emoji for intuitive visualization.
• Animated radar beams, pings, and sparks for engaging interaction.
• Instrument cards with real-time linear error values.
• Responsive layout – works on desktop and mobile.

Preview

How to Use

1. Open Total Station Accuracy Visualizer.html in your browser.
2. Use the distance slider to adjust survey range.
3. Compare how each instrument’s angular accuracy translates into linear error.
4. Expand Mathematical Calculations for detailed formulas.

Example

• At 100 m:
• 0.5″ Total Station → ~0.24 mm error
• 1″ Total Station → ~0.48 mm error
• 5″ Total Station → ~2.4 mm error
• 20″ Theodolite → ~9.7 mm error

Why Use This Tool?

• Helps compare equipment accuracy before purchase.
• Useful for field engineers planning tolerances for different distances.
• Runs completely offline — no internet required.
• Interactive, visual, and intuitive for quick decision-making.

The post Traverse Adjustment Tool first appeared on BGol.

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Total Station Accuracy Visualizer

A modern offline web tool to visualize and compare the angular accuracy vs. linear error of different Total Stations and a Theodolite.
Ideal for surveyors and engineers when deciding what instrument suits their project requirements.

Features

Supported Instruments

• High-Precision Total Station (0.5″ accuracy)
• Standard Total Station (1″ accuracy)
• General-Purpose Total Station (2″ accuracy)
• Basic Total Station (5″ accuracy)
• Theodolite (20″ accuracy)

Accuracy Visualization

• Angular Accuracy Chart → Wedge visualization of angular spread.
• Linear Error Chart → Bar chart showing error in mm at selected distance.
• Adjustable distance slider (1–5000 m) to see how error grows with range.

Built-in Calculations

• Formula: Linear Error (mm) = Distance(m) × tan(θ) × 1000
• Displays step-by-step math for each instrument (θ conversion from arcseconds).

UI & Experience

• Dark/Light Mode toggle.
• Station emoji for intuitive visualization.
• Animated radar beams, pings, and sparks for engaging interaction.
• Instrument cards with real-time linear error values.
• Responsive layout – works on desktop and mobile.

Preview

How to Use

1. Open Total Station Accuracy Visualizer.html in your browser.
2. Use the distance slider to adjust survey range.
3. Compare how each instrument’s angular accuracy translates into linear error.
4. Expand Mathematical Calculations for detailed formulas.

Example

• At 100 m:
• 0.5″ Total Station → ~0.24 mm error
• 1″ Total Station → ~0.48 mm error
• 5″ Total Station → ~2.4 mm error
• 20″ Theodolite → ~9.7 mm error

Why Use This Tool?

• Helps compare equipment accuracy before purchase.
• Useful for field engineers planning tolerances for different distances.
• Runs completely offline — no internet required.
• Interactive, visual, and intuitive for quick decision-making.

The post Total Station Accuracy Visualizer first appeared on BGol.

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Surveyor Calculator

A smart calculator built for surveyors and civil engineers, running fully offline in the browser.
Beyond standard arithmetic, it includes engineering‑focused tools for quick geometry, unit conversions, and field utilities.

Features

Standard Calculator

• All basic operations (+, −, ×, ÷).
• Memory Functions (MC, M+, M−).
• Percentage button.
• Copy result with one click .
• Calculation history log with up to 25 records.

Appearance & Usability

• Toggle Dark/Light Theme.
• Modern UI styled like a mobile calculator.
• Firework/spark animations for feedback.

☰ More Functions (Engineering Toolkit)

Click More to unlock advanced tools:

• π (Pi) constant insertion.
• Roots & Powers: √x, ∛x, x², x³.
• Geometry Calculators:
• Circle Area (from diameter).
• Cylinder Volume (from diameter & height).
• Triangle Area (from three sides using Heron’s formula).
• Survey Unit Conversions:
• Ft → m (Feet–Inch to Meters).
• m → Ft (Meters to Feet–Inch).
• → m (Chain–Link to Meters).
• m → (Meters to Chain–Link).

Productivity

• History Panel → Revisit old calculations anytime.
• Error Handling → Detects invalid inputs (e.g., impossible triangle sides).

Preview

How to Use

1. Open Surveyor Calculator.html in any browser.
2. Use it like a normal calculator.
3. Click More to access extended functions.
4. Copy results or check history as needed.

Example Usage

• Standard: 25 × 4 = 100.
• Circle: Input 12 (diameter) → Result = 113.10 (area).
• Cylinder: Input 12-8 (d=12, h=8) → Result = 904.78 (volume).
• Triangle: Input 3-4-5 → Result = 6 (area).
• Conversion: 5-6 (5′6″) → 1.676 m.

Why Use This Tool?

• Tailored for surveyors & civil engineers.
• Works completely offline (no internet needed).
• Runs on mobile, tablet, and desktop.
• Combines calculator + mini engineering toolkit in one.

The post Surveyor Calculator first appeared on BGol.

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How to Use?

Polygon Partition Tool

A specialized offline polygon partitioning tool built for land surveyors, civil engineers, and GIS practitioners.
It allows you to draw, import, partition, and calculate areas/perimeters of polygons directly in the browser.
Perfect for fieldwork and planning tasks where advanced GIS software is not accessible.

Features

Input & Setup

• Import polygon points via CSV (X, Y, Name).
• Or start with a Sample Polygon for quick demo.
• Editable Table → add, delete, or reorder points with drag‑and‑drop.
• Toggle point usage (include/exclude).

Partitioning

• Draw interactive cut lines to partition polygons.
• Auto‑fit cut → divide polygon into exact target area.
• Blue/Yellow Preview → instantly shows both sides of the partition with area + perimeter.
• Undo last partition with one click.

Measurement & Units

• Area and perimeter auto‑calculated for each partition.
• Supports unit selection: meters (m), feet (ft), or custom factor.
• Real‑time labels on partitions showing Area + Perimeter.

Outputs

• Download Partitions CSV → coordinates of each subdivided polygon.
• Download Summary CSV → partition names, areas, and perimeters (with totals).
• Export SVG Sketch → saves the visual polygon partition as SVG.

UI & Usability

• Dark/Light Theme Toggle.
• Activity Log → keeps track of actions (CSV import, cuts, undo, etc.).
• Error alerts for invalid/self‑intersecting polygons.
• Grid background with snap‑to‑edge option.

Preview

How to Use

1. Open Polygon-Partition-Tool.html in your browser.
2. Load points:

• Import CSV, or
• Use Sample polygon.

1. Use handles + cut line to partition polygon.
2. Auto‑fit to a target area or apply free cut.
3. Save outputs as CSV or SVG for reporting.

Example CSV Input

Name,X,Y
P1,0,0
P2,50,0
P3,80,20
P4,80,60
P5,50,90
P6,20,80
P7,-10,50
P8,-5,20

Why Use This Tool?

• Built for field engineers & surveyors needing polygon splits quickly.
• Works offline – no internet or GIS software needed.
• Generates ready CSV reports for documentation.
• Accurate area/perimeter calculations with unit conversion.

The post Polygon Partition Tool first appeared on BGol.

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Surveyor Multi-Converter

A powerful all-in-one offline conversion tool designed for land surveyors and civil engineers.
It helps in linear, area, volume, and slope conversions with support for both international units and local Indian units often used in field practice.

Runs directly in your browser without internet — perfect for fieldwork where network access is limited.

Features

Linear Conversion

• Convert between all standard linear units (m, cm, mm, km, inch, ft, yd, mi).
• Special support for:
• Chain & Link (1 Chain = 16 Links, 1 Link = 0.629 m).
• Feet–Inch Mode (e.g., 5-6 = 5 feet 6 inches).
• Dual input modes:
• Single value (decimal entry).
• Dual value (Chain–Link or Feet–Inch entry).
• Results can be swapped instantly with the ⇄ Reverse Button.
• Copy results easily with the Copy Button.

Area Conversion

• Supports all common area units (m², km², hectare, acre, ft², yd²).
• Includes local field units:
• Vaar (sq. yard)
• Guntha (101.17 m²)
• Small Vigha (16 guntha = 1618.72 m²)
• Vigha (24 guntha = 2428.08 m²)
• Are (100 m²)
• Brass (100 ft²) – widely used in construction works.
• Handles compound input formats like Vigha–Guntha (3-5 = 3 Vigha 5 Guntha).

Volume Conversion

• Convert between m³, L, MLt, km³, ft³.
• Includes Brass (100 ft³) – used in stone, aggregate, and concrete works.

Slope Conversion & Visualization

• Converts slope across Degrees Percent 1 in N.
• Includes a triangle visualization of slope for better field understanding.
• Handy for road, canal, and embankment engineers.

Preview

Productivity Boosters

• History (last 5 conversions) → Quickly reuse previous unit pairs.
• Reverse Button → Instantly swap from/to units.
• Copy Button → Copy results to clipboard in one click.
• Dark/Light Theme → Toggle based on preference or field conditions.

How to Use

1. Open Linear, Area, Volume Converter.html in any browser.
2. Choose the module: Linear / Area / Volume / Slope.
3. Enter values and select units.
4. Results appear instantly with animations .

Example Usage

• Linear: 5-6 (5 ft 6 in) → 1.676 m
• Area: 3-5 (3 Vigha 5 Guntha) → 8064.5 m²
• Volume: 1 Brass → 100 ft³ = 2.8317 m³
• Slope: 5° → 8.75% = 1 in 11.43

Why Use This Tool?

• Covers units not available in typical converters (Chain–Link, Vigha, Brass, Feet–Inch).
• Works offline, ideal for survey sites with no network.
• Built for surveyors, civil engineers, and contractors.
• Minimal UI, fast, and reliable.

The post Multi-Converter (Linear, Area, Volume, Slope) first appeared on BGol.

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Area Calculator of Known Shapes

A fun and interactive browser-based tool to calculate the area of common 2D shapes such as:
Square, Rectangle, Triangle, Circle, Trapezoid, and Parallelogram .
Runs completely offline and works on any device with a browser.

Features

• Supports 6 Known Shapes:
• Square → A = x²
• Rectangle → A = b × h
• Triangle → A = ½ × b × h
• Circle → A = πr²
• ⬡ Trapezoid → A = ½(a + b) × h
• ▭ Parallelogram → A = b × h
• Dark/Light Theme Toggle
• Animated Sparkle Effect when results appear
• Responsive Design – Works smoothly on mobile, tablet, or desktop
• Instant Calculation as you type your values
• No installation required – just open the HTML file

Preview

How to Use

1. Open Area Calculator of Known Shapes.html in your browser.
2. Select the shape you want to calculate (e.g., Square, Circle, etc.).
3. Enter the required dimensions (side, base, height, radius, etc.).
4. The tool will:

• Instantly compute the area
• Display it with a highlight + sparkle animation

Example Input

• Square: Side = 10 → Result = 100
• Circle: Radius = 5 → Result ≈ 78.54
• Trapezoid: a = 6, b = 10, h = 4 → Result = 32

Why Use This Tool?

• Great for students learning geometry
• Useful for surveyors/engineers in quick field calculations
• Attractive UI with spark animations and responsive cards
• Works offline, no internet needed

The post Area Calculator of Known Shapes first appeared on BGol.