.. _PrinciplesOfScaling:

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Principles of Scaling
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Lab Materials
=============

Download this: :download:`Lab Packet <../_static/labs/PrinciplesOfScaling/materials/PrinciplesOfScalingLabPacket.pdf>`

Equations and Assumptions
-------------------------

Assume the focal length of the camera used to collect the photos in this lab is 6 inches.

Use the following conversions for this lab:

| 1 inch = 2.54 cm = 25.4 mm
| 1 mile = 1609 meters
| 1 meter = 100 cm = 1000 mm
| mm = millimeter
| cm = centimeter

Scaling Relationships
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.. math::

    \frac{d}{D} &= \frac{1}{\textrm {scale factor}} = \frac{f}{H}

    d &= \textrm {map distance}  \\
    D &= \textrm {ground distance}  \\
    f &= \textrm {camera focal length}  \\
    H &= \textrm {flying height}  \\

Lab Content
===========

Objective
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Students will compare similar features in aerial photos and USGS 1:24000 topographic maps to determine:

1) The scale of the aerial photos
2) The flying height of the aircraft
3) The area of features in the photos

Data
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Topographic map and aerial photos contained in the lab packet.

Procedure
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1) Identify three features, such as highway intersections, that are visible in both aerial photos and on the USGS topographic map.
2) Measure the length of the three features in the aerial photos and on the topographic map in millimeters.
3) Using the measurements you collected and the known scale of the topographic map calculate the scale of the aerial photos.
4) Average the the scale factors calculated for each measurement to get the average scale for each aerial photo.
5) After ascertaining the scale of the photos, use it to determine the flying height of the aircraft for both the photos in:

  a) meters
  b) feet

6) Using the average scale factor calculated from your measurements calculate the area in of a 2 inch by 2 inch section of each of photo in:

  a) square meters
  b) square miles

7) Find the area of the Gainesville Airport's runway using the large photo and the small photo in:

  a) square feet
  b) square meters
  c) acres


Metadata
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| Title:Principles of Scaling
| CreationDate:06/20/2013
| SoftwareUsed:None
| SoftwareVersion:None