JavaScript Maps SDK

Add a custom Style Layer

Use a custom style layer to render custom WebGL content. Requires Trimble Maps v3.0.0 or later. 


<!doctype html>
<html lang="en">
    <head>
        <meta charset="utf-8" />
        <link rel="stylesheet" href="https://maps-sdk.trimblemaps.com/v4/trimblemaps-4.2.3.css" />
        <script src="https://maps-sdk.trimblemaps.com/v4/trimblemaps-4.2.3.js"></script>
        <style>
            body { margin: 0; padding: 0; }

            html,body,#map {
                height: 100%;
            }
        </style>
    </head>
    <body>
        <div id="map"></div>

        <script>
            TrimbleMaps.setAPIKey('YOUR_API_KEY_HERE');
        const map = new TrimbleMaps.Map({
        container: 'map',
        zoom: 3,
        center: [7.5, 58],
        style: TrimbleMaps.Common.Style.TRANSPORTATION,
        antialias: true // create the gl context with MSAA antialiasing, so custom layers are antialiased
    });

    // create a custom style layer to implement the WebGL content
    const highlightLayer = {
        id: 'highlight',
        type: 'custom',

        // method called when the layer is added to the map
        // Search for StyleImageInterface in https://developer.trimblemaps.com/maps-sdk/api/
        onAdd (map, gl) {
        // create GLSL source for vertex shader
            const vertexSource = `#version 300 es

            uniform mat4 u_matrix;
            in vec2 a_pos;
            void main() {
                gl_Position = u_matrix * vec4(a_pos, 0.0, 1.0);
            }`;

            // create GLSL source for fragment shader
            const fragmentSource = `#version 300 es

            out highp vec4 fragColor;
            void main() {
                fragColor = vec4(1.0, 0.0, 0.0, 0.5);
            }`;

            // create a vertex shader
            const vertexShader = gl.createShader(gl.VERTEX_SHADER);
            gl.shaderSource(vertexShader, vertexSource);
            gl.compileShader(vertexShader);

            // create a fragment shader
            const fragmentShader = gl.createShader(gl.FRAGMENT_SHADER);
            gl.shaderSource(fragmentShader, fragmentSource);
            gl.compileShader(fragmentShader);

            // link the two shaders into a WebGL program
            this.program = gl.createProgram();
            gl.attachShader(this.program, vertexShader);
            gl.attachShader(this.program, fragmentShader);
            gl.linkProgram(this.program);

            this.aPos = gl.getAttribLocation(this.program, 'a_pos');

            // define vertices of the triangle to be rendered in the custom style layer
            const helsinki = TrimbleMaps.MercatorCoordinate.fromLngLat({
                lng: 25.004,
                lat: 60.239
            });
            const berlin = TrimbleMaps.MercatorCoordinate.fromLngLat({
                lng: 13.403,
                lat: 52.562
            });
            const kyiv = TrimbleMaps.MercatorCoordinate.fromLngLat({
                lng: 30.498,
                lat: 50.541
            });

            // create and initialize a WebGLBuffer to store vertex and color data
            this.buffer = gl.createBuffer();
            gl.bindBuffer(gl.ARRAY_BUFFER, this.buffer);
            gl.bufferData(
                gl.ARRAY_BUFFER,
                new Float32Array([
                    helsinki.x,
                    helsinki.y,
                    berlin.x,
                    berlin.y,
                    kyiv.x,
                    kyiv.y
                ]),
                gl.STATIC_DRAW
            );
        },

        // method fired on each animation frame
        render (gl, matrix) {
            gl.useProgram(this.program);
            gl.uniformMatrix4fv(
                gl.getUniformLocation(this.program, 'u_matrix'),
                false,
                matrix
            );
            gl.bindBuffer(gl.ARRAY_BUFFER, this.buffer);
            gl.enableVertexAttribArray(this.aPos);
            gl.vertexAttribPointer(this.aPos, 2, gl.FLOAT, false, 0, 0);
            gl.enable(gl.BLEND);
            gl.blendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA);
            gl.drawArrays(gl.TRIANGLE_STRIP, 0, 3);
        }
    };

    // add the custom style layer to the map
    map.on('load', () => {
        map.addLayer(highlightLayer, 'crimea-fill');
    });
    </script>
  </body>
</html>
Last updated June 26, 2025.