{{ :manual:user_guide:ic_on_board_calibration_alt.png?nolink|}}====== Image Map Calibration ======

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===== About =====

This feature enables calibrating of an image of a map and placing it over a background map. For example when you go to the ZOO or a park simply take a picture of its detailed plan displayed on a board at the entrance. After that, you can calibrate the photo according to your background map and use it for your further navigation.

<wrap info>Available only with **[[https://www.locusmap.app/premium|Premium]]**</wrap>
===== 1. Get a map picture =====
  * open the function in <wrap box>Menu > All features > Map tools > Image map calibration</wrap>, a dialog appears
  * tap **Take** to take a photo with your phone camera - the more quality camera, the better
  * or **Select** to choose the photo from your device memory, from Dropbox etc.

===== 2. Calibrate the map picture =====
  * tap //Add// and choose a **distinct point** (a hill summit, crossroads etc.) on your picture\\ {{ :manual:user_guide:maps_tools:calibr2.png?nolink |}}
  * tap {{:manual:user_guide:ic_map_alt.png?nolink&30|}} in //Map coordinates menu// and choose **the same point** on your background map\\ {{ :manual:user_guide:maps_tools:calibr3.png?nolink |}}
  * repeat this procedure **4 times** - try to select points making a rectangle. You can edit their positions by tapping {{:manual:user_guide:ic_edit_alt.png?nolink&30|}} or remove them.\\ {{ :manual:user_guide:maps_tools:calibr.png?nolink |}}
===== 3. Generate your calibrated map =====
  * when you are ready with your four points the status line **turns green** and the //Create// button activates\\ {{ :manual:user_guide:maps_tools:calibr4.png?nolink |}}
  * calibration points overview appears - indicates their **deviation**.\\ {{ :manual:user_guide:maps_tools:calibr5.png?nolink |}}\\ When it is not too significant you can name the new map and proceed to its rendering
<WRAP round tip >If you have chosen a big image it is highly recommended to check **Optimize map** to divide the map image into many small maps (tiles) bundled into one file.
</WRAP>
==== Save the calibration configuration for later use ====
If you have **more map images of the same size and scale** to calibrate you can use one configuration for calibrating them all:
  - calibrate the first image
  - **save the calibration configuration**:\\ {{ :manual:user_guide:maps_tools:calibr11.png?nolink |}}
  - open the next image
  - calibrate
  - repeat ad hoc.
===== 4. Use the calibrated map =====
Your calibrated map appears now as an **overlay** and can be managed in **[[manual:user_guide:items:management|Map Items]]** box or in the **[[manual:user_guide:mainscr_lpanel#active_items|Active items]]** of the **content panel**. There you can change the opacity of the calibrated map by selecting it and moving the opacity slider:\\ {{ :manual:user_guide:maps_tools:calibr9.png?nolink |}}

<WRAP center round tip>
If you want to use the calibrated map elsewhere, e.g. in Google Earth, they are stored as KMZ files in the **///Locus/MapItems/calibrated_maps//** directory.
</WRAP>