# External map layer

<figure><img src="/files/BJDt1WrPdZbv3brKZpsj" alt=""><figcaption><p>In Map settings >> External layer</p></figcaption></figure>

{% hint style="success" %}
sample map with swiss topo layer: <https://racemap.com/player/swiss-topo-sample>

URL to call external layer: <https://wms.geo.admin.ch/?SERVICE=WMS&REQUEST=GetMap&VERSION=1.3.0&LAYERS=ch.swisstopo.swissimage&STYLES=default&CRS=EPSG:3857&BBOX={bbox-epsg-3857}&WIDTH=256&HEIGHT=256&FORMAT=image/png>

more about swiss topo. <https://www.geo.admin.ch/en/geo-services/geo-services/portrayal-services-web-mapping/web-map-services-wms.html>&#x20;
{% endhint %}

```
https://wms.geo.admin.ch/
     ?SERVICE=WMS
     &REQUEST=GetMap
     &VERSION=1.3.0
     &LAYERS=ch.swisstopo.swissimage
     &STYLES=default
     &CRS=EPSG:3857
     &BBOX={bbox-epsg-3857}
     &WIDTH=256
     &HEIGHT=256
     &FORMAT=image/png
```

|                            |                                     |
| -------------------------- | ----------------------------------- |
| SERVICE                    | WMS                                 |
| REQUEST                    | GetMap                              |
| VERSION                    | 1.3.0 or 1.1.0                      |
| STYLES                     | empty                               |
| CRS (1.3.0) or SRS (1.1.0) | EPSG:3857                           |
| BBOX                       | {bbox-epsg-3857} a variable         |
| WIDTH                      | 256; same as tile size respectively |
| HEIGHT                     | 256; same as tile size respectively |
| FORMAT                     | image/png or image/jpeg             |
| TRANSPARENT                | true                                |

LAYERS: different, available in GetCapabilities e.g. <https://wxs.ign.fr/`yourkey`/geoportail/r/wms?SERVICE=WMS\\&VERSION=1.3.0\\&REQUEST=GetCapabilities>

### Use GeoTIFF

{% file src="/files/YisBIpkK4t0DCYG36i5v" %}
Download the sample file GeoTiff
{% endfile %}

1. mapbox style editor \
   "Create a style" and "Start from scratch"

   <figure><img src="/files/yv2IQIG4pPXjLbGnkqKj" alt=""><figcaption></figcaption></figure>
2. Add a "Custom layer" and upload the GeoTIFF or KML file.&#x20;

   <figure><img src="/files/xG6k5ANBbNp5V2mARTQI" alt=""><figcaption></figcaption></figure>
3. mapbox creates the layer ID once the GeofTIFF is uploaded \
   `racemap.48p1az6b` <br>

   <figure><img src="/files/j4aE3nStUstyXSOqdJqR" alt=""><figcaption></figcaption></figure>
4. RACEMAP >> Map Settings >> External Layers \
   Add URL as external WMS: `https://api.mapbox.com/v4/racemap.48p1az6b/{z}/{x}/{y}.png?access_token={privateKeyMapbox}` and replace `{privateKeyMapbox}` with your mapbox key.&#x20;

   <figure><img src="/files/phdpn4k5F9Pq207GlkKE" alt=""><figcaption></figcaption></figure>

The result shows the original TIFF file: <https://racemap.com/player/6a01a8d5bd1f6d9fc6f4f50d>&#x20;

#### Remove the border in the GeoTIFF

1. Free download of [QGIS](https://qgis.org/)&#x20;
2. Load GeoTIFF and create a new GeoPackage-layer

   <figure><img src="/files/rusLQX8XqUYlpgQO3Axu" alt=""><figcaption></figcaption></figure>
3. Select "Polygon"\
   ![](/files/Zb2PcpuPkwzgnsYkoEgY)
4. Define borders with the pencil and polygon tool - left click: add point, right click: finish polygon.&#x20;

   <figure><img src="/files/GwvMVrcUdOhbwJYHiLmD" alt=""><figcaption></figcaption></figure>
5. Raster >> Extraction >> Clip Raster by Mask Layer: Data outside the polygon is removed.

<figure><img src="/files/Ba5BVy8H2K3Wzq1S6Xp4" alt=""><figcaption></figcaption></figure>

6. Select the GeoTIFF as the input file, the mask layer to use (previously created), enable "Create an output alpha band" and "Keep resolution of input raster".

   <figure><img src="/files/Ixm2UFP4pxbhGaM2aVuy" alt=""><figcaption></figcaption></figure>

   6\. QGIS generates a new GeoTIFF file, which you now use to create another mapbox layer.\
   ![](/files/D2lXFXupPHqNGwcKHUWc)

Sample: <https://racemap.com/player/external-layer-mask/>&#x20;

{% hint style="info" %}
We needed to run "Fix Geometries" in QGIS before extraction processed successfully.&#x20;
{% endhint %}


---

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