Dynamic pins on a map

Objectives

Generate a presentation with the following features:

• Dynamically move a pin on a map.
• Convert latitude and longitude into X and Y coordinates on an image

Solution

Warning: For demonstration purposes, the calculation method for determining the geographical position of the marker has been greatly simplified. This is an approximation that does not follow any scientific method for converting geographical coordinates.

Here’s how to construct an ODP template to achieve this with Carbone:

1. Insert the map in the template

2. Define two fixed reference points on your your side

   • Record their GPS coordinates (latitude and longitude)
   • Identify their X and Y positions on the inserted map by placing a shape and noting its X and Y positions

   Example:

    Name    | PosX  | PosY  | Latitude  | Longitude
    Darwin  | 7.87  | 0.31  | -12.455   | 130.839
    Perth   | 1.58  | 8.77  | -31.953   | 115.863

   • Compute the coefficient needed for the approximate conversion :

   Example:

   CoeffX = (7,87-1.58)/(130.839-115.863) = 0,420
   CoeffY = (0.31-8.77)/(-12.455-(-31.953)) = 0,4334 

3. Define the dynamic position of the shape

   • Keep only one shape on the map in the template, which will be used for movement
   • Right-click on the shape, go to the Alt text menu, and specify the transformations to apply to the longitude {d.location[i].longitude} and latitude {d.location[i].latitude} values, using :transform() formatter

   Example:

   {d.location[i].longitude:sub(115.863):mul(0.420):sub(7.87):add(1.58):transform(x,cm)}
   {d.location[i].latitude:sub(-31.953):mul(-0.4334):add(8.77):transform(y,cm)}

   Note: Make sure to use a shape (not an image) to apply the `transform formatter

4. Add a placeholder

   • Insert a temporary image
   • Right-click on it, go to the Alt text menu, and specify the path of the illustrative image

   Example: {d.location[i].image}

And there you go!

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