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en:help:v2:maps:file-based-calibrate [2019/10/17 14:56]
alpinequest
en:help:v2:maps:file-based-calibrate [2020/01/10 09:42]
alpinequest
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 ====== How to calibrate an image to use it as a map? ====== ====== How to calibrate an image to use it as a map? ======
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-The application allows you to use regular images as maps. In order to correctly locate items on this map (points, tracks, etc.), the application must know what is the exact area covered, this is done by the calibration process: after displaying the image, you must match 4 points with another existing and correct map. This process is done only one time, then the image is imported ​as a regular map file.+The application allows you to use regular images as maps. In order to correctly locate items on this map (points, tracks, etc.), the application must know what is the exact area covered, this is done by the calibration process: after displaying the image, you must match 4 points with another existing and correct map. This process is done only one time, then the image is converted ​as a regular map file.
  
 {{:​icon_help.png?​nolink}} The calibration process used by this application requires 4 points, which is enough to correctly match an image over a base map without knowing the exact map projection which is used, and gives satisfactory result for maps with limited areas. {{:​icon_help.png?​nolink}} The calibration process used by this application requires 4 points, which is enough to correctly match an image over a base map without knowing the exact map projection which is used, and gives satisfactory result for maps with limited areas.
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 For each calibration point: For each calibration point:
-  * Tap the button of this calibration point {{:​icon_06.png?​nolink}} to select the arrows icon. In this state, you'll be able to move the calibration within the image to calibrate;​ +  * Tap the button of this calibration point {{:​icon_06.png?​nolink}} to select the arrows icon. In this state, you'll be able to move the calibration ​point within the image to calibrate;​ 
-  * Tap and old the arrows icon on the map {{:​icon_07.png?​nolink}},​ and move the calibration point over a map feature that is clearly visible on both the base map and the image to calibrate. Here for example, we choose a railroad crossing;+  * Tap and hold the arrows icon on the map {{:​icon_07.png?​nolink}},​ and move the calibration point over a map feature that is clearly visible on both the base map and the image to calibrate. Here for example, we choose a railroad crossing;
   * Tap the button of this calibration point {{:​icon_06.png?​nolink}} again to select the padlock icon. In this state, you'll be able to move the image over the base map;   * Tap the button of this calibration point {{:​icon_06.png?​nolink}} again to select the padlock icon. In this state, you'll be able to move the image over the base map;
-  * Reduce the opacity of the image to calibrate using the opacity slider {{:​icon_08.png?​nolink}} to make the base map visible, and move the calibration point to the correct location {{:icon_08.png?​nolink}} on this one. Only pay attention to the point to calibrate and ignore other features ​around: they will only match when the four calibration points are correctly placed.+  * Reduce the opacity of the image to calibrate using the opacity slider {{:​icon_08.png?​nolink}} to make the base map visible, and move the calibration point to the correct location {{:icon_09.png?​nolink}} on this one. __Only ​pay attention to the point to calibrate and ignore other features ​around__: they will only match when the four calibration points are correctly placed.
  
 Repeat those steps for the three other calibration points. Repeat those steps for the three other calibration points.

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