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Measuring with Camera

pcMapper Db lets you measure height and distance using the camera on your device. You can also capture the measured height directly to an attribute of a feature. The measure is approximate and assumes that you are positioned in the front of the object, for example a building or a tree, more or less horizontally (i.e., not on a slope). It is best suited for measuring heights of about 2-20 meters (6-60 feet) at a distance of 10-50 meters (15-150 feet).
Notice: it is assumed that you hold the camera at eye height or about 1.7 meters (5.6 / 5’7” feet) above the ground when measuring or calibrating.

Calibrating the camera

The first step is to calibrate the camera for pcMapper. This is necessary since the sensor parameters varies between different devices. To do this you must select an object with a known size (width and height) and be at known distance away from it. For example using a door, a soccer goal, a basketball hoop or a person. In the following example we are going to use a garden shed as a reference object.
  1. Tap the [Find / DB / 3D] button on the bottom toolbar
  2. Tap the [Menu] key and select Measure with Camera
  3. Point the camera at the bottom of the object
  4. Tap Get Distance
  5. Tap the [Menu] key and select Distance
  6. Enter the actual distance to the object
  7. Point the camera at the center of the object and tap Take Picture
  8. Drag the vertical and horizontal lines so that they fence in the object
  9. Press the [Menu] key and select Calibrate
  10. Enter the actual width of the object (meters)
  11. Enter the actual height of the object (meters)
  12. Tap the [Back] key
Tip: you can re-calibrate the camera at any time.

Measuring height and distance

Once the camera has been calibrated, you can measure the width and height of objects.
  1. Tap the [Find / DB / 3D] button on the bottom toolbar
  2. Press the [Menu] key and select Measure with Camera
  3. Point the camera at the bottom of the object you want to measure
  4. Tap Get Distance (this is the measured distance to the object) or enter the distance:
    a) Tap the [Menu] key and select Distance
    b) Enter the actual distance to the object
  5. Point the camera at the center of the object and tap Take Picture
  6. Drag the vertical (and horizontal) lines so that they fence in the object. You can see how the measurement is updated at the top of the screen
  7. Press the [Back] key


Tip: You can skip steps 5-6 (Take Picture) by pointing the camera at the top of the object and reading the measurements at the top of the screen.

Capturing height to an attribute

This requires that an attribute field has been defined to store heights - see Defining Metadata.
  1. Select the feature in the map you want to assign the height to
  2. Tap the [Find / DB / 3D] button on the bottom toolbar
  3. Tap the [Menu] key and select Measure with Camera
  4. Point the camera at the bottom of the object you want to measure
  5. Tap Get Distance (this is the measured distance to the object) or enter the distance:
    a) Press the [Menu] key and select Distance
    b) Enter the actual distance to the object
  6. Point the camera at the center of the object and tap Take Picture
  7. Drag the vertical (and horizontal) lines so that they fence in the object. You can see how the measurements are updated at the top of the screen
  8. Tap Get Height (this is the measured height of the object and will be stored in the defined attribute field)
  9. Press the [Back] key
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