AMap.GeoJSON is not a constructor

This error usually occurs when the AMap GeoJSON library is not properly loaded or initialized. Here are some steps you can try to fix it:

1. Make sure that the AMap GeoJSON library is properly loaded before using it in your code. You can do this by including the following script tag in your HTML file:

<script src="https://webapi.amap.com/maps?v=1.4.15&key=YOUR_API_KEY"></script>

Replace `YOUR_API_KEY` with your actual AMap API key.

2. Check if the AMap object is properly initialized before using the GeoJSON library. You can do this by adding a callback function to the AMap script tag like this:

<script src="https://webapi.amap.com/maps?v=1.4.15&key=YOUR_API_KEY&callback=initMap"></script>

Then define the `initMap` function in your JavaScript code, and make sure to include the GeoJSON library initialization code inside it, like this:

function initMap() {
  var map = new AMap.Map('map-container', {
    // map options here
  });
  
  // initialize GeoJSON library here
  var geoJSON = new AMap.GeoJSON({
    // GeoJSON options here
  });
  
  // other code here
}

3. Make sure that the AMap GeoJSON library is compatible with the version of AMap you are using. Check the version numbers in the documentation and make sure they match.

If none of these steps work, try searching for similar issues in the AMap documentation or forums, or contacting their support team for help.