Photogrammetry

Overview: Allows two-dimensional numerical rectification of photographic images.

Entry into Module:

This module of the program is normally entered by clicking on the REC-TEC block in the upper left of the REC-TEC Window causing the drop-down menu to appear. Place the cursor and click on Photogrammetry to initiate this module.

Under certain circumstances, the user may choose to use the Files block instead of the drop-down menu approach. Selecting any file with a .PGM extension in the Dialog box accessed from either the Open Single File or Open Multiple Files block opens this module.

Selecting AutoLoad [ON] from either the Setup Menu or the AutoLoad Icon on the upper right side (third line) of the REC-TEC Window automatically loads the scenario that was on the screen when the module was closed, either individually, or when the program was closed. With AutoLoad [OFF] on the main REC-TEC Window, modules will start without loading a file.

Data Entry:

This module contains the following data entry blocks within the leftmost frame:

Calibration Point

· Photograph (1-4): – X and Y Coordinates for Photograph Points (1-4)

· Scale Diagram (1-4): – X and Y Coordinates for Scale Diagram Points (1-4)

· Computed Point (1-4): – Program “solves” for Scale Diagram Points (1-4)

Clear All Data (Command Button) – Clears ALL Data

Clear Table Data Only (Command Button) – Clears Table Data only

Output:

· Calibration: Shows eight (8) Calibration Points (Matrix Solution)

· Y – Vertex (Button) – Shifts Y-vertex flipping Graphics

· Photograph (N): – X and Y Coordinates for Photograph Point (N)

· Scale Diagram (N): – X and Y Coordinates for Scale Diagram Point (N)

Grid ON/OFF (Command Button) – Toggles Grid in Graphics

Lines ON/OFF (Command Button) – Toggles some Lines in Graphics

Save Points to Table (Command Button) – Saves Displayed Points to Table

Options:

Several Command Buttons appear in a frame located at the lower right corner of the module Window. The Command Buttons allow the user to engage options including the option to Open and Save the data required to generate the scenario shown on the screen at the time the file was saved.

· Open .PGM File – Calls up a Dialog box, which Opens any pre-existing .PGM file and displays the output results.

· Save .PGM File – Calls up a Dialog box, which Saves data on the screen to files with any user-selectable filenames. This is independent of the automatic saving as “LastFile.PGM” of the data at the close of this module or the close of the program.

· View Table of Points – Opens a word processor (set by the user in Setup) with a file showing the Calibration and Additional Points for the Photograph and Scale Diagram.

· Help – Opens a word processor (set by the user in Setup) with a file showing the operation of the Photogrammetry module.

· N – This button toggles a graphical number pad on the screen that can be used to enter data into the input boxes without using your keyboard number pad. This may be useful for presentations as data entry can be accomplished using a wired/wireless mouse.

IPTM Publications – The following publication is available from IPTM 1-904-620-4786 or http://www.iptm.org and is recommended for further reading.

BASIC PHOTOGRAMMETRY by George M. Bonnett contains an article entitled Discusses basic 2-Dimensional Photogrammetry using Numerical Rectification.