# Map layers and basemaps

## Sources, Layers, and Source Types

The main layer [source type](https://docs.mapbox.com/mapbox-gl-js/style-spec/sources/) in Moped is GeoJSON. The pattern for adding a source and layer to a `react-map-gl` map is to use the [Source](https://visgl.github.io/react-map-gl/docs/api-reference/source) and [Layer](https://visgl.github.io/react-map-gl/docs/api-reference/layer#layer) components. These two components are abstraction of Mapbox GL [sources](https://docs.mapbox.com/mapbox-gl-js/style-spec/sources/) and [layers](https://docs.mapbox.com/mapbox-gl-js/style-spec/layers/). The Source component is responsible for the data and the Layer component is used to style the data of the source. An example of JSX for a vector tile layer is below.

```javascript
<Source
  key={config.layerIdName}
  type="geojson"
  data={theGeojsonData}
>
  <Layer
    key={config.layerIdName}
    {...theOtherlayerProps}
  />
</Source>
```

## GeoJSON layers

Layers that are created from user input (like selecting from the CTN segments or intersection layer or drawing lines or points) require a source with [type](https://visgl.github.io/react-map-gl/docs/api-reference/source#type) `geojson` and, in Moped, the geojson is formatted as a GeoJSON feature collection.

The CTN segments and intersection points are also populated with GeoJSON data queried from AGOL feature servers called [CTN segments FeatureServer](https://services.arcgis.com/0L95CJ0VTaxqcmED/ArcGIS/rest/services/CTN_Segments_MOPED_FS/FeatureServer) and [COA Intersection points FeatureServer](https://services.arcgis.com/0L95CJ0VTaxqcmED/ArcGIS/rest/services/LOCATION_coa_intersection_points/FeatureServer).

## Base Maps

### Default basemap

In Moped, the default basemap style is [Mapbox Light](https://www.mapbox.com/maps/light) and the streets layer for the [mapStyle prop](https://visgl.github.io/react-map-gl/docs/api-reference/static-map#mapstyle) in `react-map-gl` is `mapbox://styles/mapbox/light-v10`.

### Aerial Imagery basemap

To add aerial imagery, a Nearmap layer is added as a raster tile set. Nearmap access and the API key is managed by CTM and can be inquired about through the [COA ServiceNow Portal](https://atx.service-now.com/sp). The API key is stored in the DTS 1Password Developers vault and is titled **Moped Nearmap API Key.**

The aerial basemap is added by providing a raster tile configuration that uses the Nearmap API endpoint along with the API key to provide aerial tiles. A sample configuration is shown below. A Mapbox example of using a custom tile set is [here](https://docs.mapbox.com/mapbox-gl-js/example/map-tiles/). This configuration is passed to the [mapStyle prop](https://visgl.github.io/react-map-gl/docs/api-reference/static-map#mapstyle) of  a `react-map-gl` map much like the default streets basemap above. This time, an object is passed instead of the string source of a Mapbox style.

```javascript
{
  sources: {
  "raster-tiles": {
      id: "aerial-tiles",
      type: "raster",
      tiles: [
        `https://api.nearmap.com/tiles/v3/Vert/{z}/{x}/{y}.jpg?apikey=${NEARMAP_KEY}`,
      ],
      tileSize: 256,
    },
  },
  layers: [
    {
      id: "aerial-tiles",
      type: "raster",
      source: "aerial-tiles",
      minzoom: 0,
      maxzoom: 22,
    },
  ],
}
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://atd-dts.gitbook.io/moped-documentation/dev-guides/maps-and-geospatial-data/map-layers-and-basemaps.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.