AllRounder.ai
Chapters in this course

Enrol to start learning

Reading is open to everyone. Enrolling is free, and it is what unlocks the audio lessons, practice tests and progress tracking.

Enrol free

4. Graphical Radial Triangulation

This chapter delves into the processes involved in aerial triangulation and photogrammetry, emphasizing techniques for achieving accurate maps from aerial photographs. It explains the significance of ground control points, various types of aerial triangulation methods, and the use of different photogrammetric software. Additionally, it covers the creation of mosaics, orthophotos, and stereo-plotting instruments while highlighting the advancements in digital photogrammetry.

Sections

Graphical Radial Triangulation

Graphical radial triangulation is a technique used in photogrammetry to accurately position photographs using simple instruments.

4.26 Section Overview

Start current section content and materials

4.26.1 Steps for graphical radial triangulation

Graphical radial triangulation is a method used to align aerial photographs and map out terrain using simple tools.

4.26.2 Common scale in triangulation

This section covers the methods and processes involved in achieving a common scale in photogrammetry and triangulation, focusing on graphical and block triangulation techniques.

4.27 Scaling in Arundel’s method

This section details the Arundel method for graphical radial triangulation, emphasizing procedures for scaling photographs in aerial mapping.

Block Triangulation

Block triangulation enhances internal strength and accuracy compared to strip triangulation methods in photogrammetry.

4.14.1 Section Overview

Start current section content and materials

4.14.1.1 Analog aerial triangulation

This section discusses the analog aerial triangulation method, outlining its process for obtaining accurate mapping from aerial photographs.

4.14.1.2 Semi-analytical aerial triangulation

This section discusses semi-analytical aerial triangulation, detailing methods and graphical techniques for processing aerial photographs and establishing control points.

4.14.1.3 Analytical aerial triangulation

This section covers the process of analytical aerial triangulation, including importance, techniques, and methods for achieving accurate aerial photography.

4.14.1.4 Digital aerial triangulation

This section outlines the process and techniques involving digital aerial triangulation in photogrammetry, detailing various methods and aspects related to it.

Orientation parameters

This section details the six orientation parameters necessary for aerial triangulation and explains how control points help determine these parameters.

4.14.2 Section Overview

Start current section content and materials

Bundle adjustment

Bundle adjustment is an essential algorithm in triangulation that adjusts all photos simultaneously to create an accurate spatial model using light ray intersections.

4.14.3 Section Overview

Start current section content and materials

Photogrammetric Mapping

Photogrammetric mapping involves using aerial photography and photogrammetric techniques to measure and analyze land for topographical mapping, curating essential data through methods like mosaicing and digital imagery.

4.15 Section Overview

Start current section content and materials

4.15.1 Mosaics

Mosaics involve assembling overlapping aerial photographs to create a continuous representation of the Earth's surface, essential for accurate mapping.

4.15.2 Stereo-plotting instruments

This section discusses stereo-plotting instruments that establish accurate 3D coordinates from aerial imagery.

4.15.3 Types of stereo-plotting instruments

This section describes various types of stereo-plotting instruments and their application in photogrammetry.

4.15.4 Photogrammetric software

This section discusses various types of photogrammetric software used for analyzing and mapping in photogrammetry, categorizing them into free source and commercial software.

Unit Summary

This unit provides an overview of photogrammetry, covering key concepts and methods in graphical and aerial triangulation.

5.0 Section Overview

Start current section content and materials

Solved Examples

This section outlines a series of solved examples that demonstrate the principles and applications of photogrammetry, particularly focused on calculating scales, flying heights, and lengths of lines on photographs.

5.1 Section Overview

Start current section content and materials

5.1.1 Example 4.1
5.1.2 Example 4.2

This section discusses graphical radial triangulation methods in photogrammetry, emphasizing the processes of selecting control points and adjusting photos to a common scale.

5.1.3 Example 4.3
5.1.4 Example 4.4
5.1.5 Example 4.5
5.1.6 Example 4.6
5.1.7 Example 4.7
5.1.8 Example 4.8

This section describes the graphical radial triangulation process and the use of photogrammetry in mapping.

5.1.9 Example 4.9

This section discusses the process of radial line triangulation using graphical methods and outlines the principles of aerial triangulation and their significance.

5.1.10 Example 4.10

Learning Objectives

  • Graphical radial triangulation is essential for establishing accurate control points in aerial photogrammetry.

  • Aerial triangulation methods can be categorized into analog, semi-analytical, analytical, and digital methods, each with unique advantages.

  • Mosaics offer a continuous photographic representation with varying accuracy, and orthophotos provide geometrically corrected images for accurate readings.

Key Concepts

Radial Triangulation

A method used in photogrammetry to determine the position of points on the ground by forming radials from the principal point of photographs.

Bundle Adjustment

A technique in photogrammetry where multiple images are adjusted simultaneously to fit together, improving the accuracy of the 3D model.

Orthophoto

An aerial photograph geometrically corrected to have a uniform scale and serve as an accurate map substitute.

Stereo-plotting

The process of creating 3D models from two overlapping aerial images through stereoscopic vision.

Practice Exercises

Total Questions

2

Estimated Time

4 min

Passing Score

70%

Instructions

  • Read each question carefully
  • You can use hints if you need help
  • Complete all questions before submitting

1 more question available

Enrol free