Named Maps are essentially the same as Anonymous Maps except the MapConfig is stored on the server, and the map is given a unique name. You can create Named Maps from private data, and users without an API Key can view your Named Map (while keeping your data private).
The Named Map workflow consists of uploading a MapConfig file to CartoDB servers, to select data from your CartoDB user database by using SQL, and specifying the CartoCSS for your map. The response back from the API provides the name of your MapConfig as a template map; which you can then use to create your Named Map details, or [fetch XYZ tiles](#fetching-xyz-tiles-for-named-maps) directly for Named Maps. You can also use the MapConfig that you uploaded to create a map using [CartoDB.js](#use-cartodbjs-to-create-named-maps) for Named Maps.
The MapConfig generated template map is static and may contain placeholders, enabling you to modify your map's appearance by using variables. Templates maps are persistent with no preset expiration. They can only be created, or deleted, by a CartoDB user with a valid API KEY (See [auth argument](#arguments)).
Uploading a MapConfig produces a template map for your Named Maps. Such as MapConfigs are uploaded to the server, "template".json files are uploaded to the server for Named Maps. The template.json files contain the [MapConfig specifications](http://docs.cartodb.com/cartodb-platform/maps-api/mapconfig/).
**Note:** There is a limit of 4,096 Named Maps allowed per account. If you need to create more Named Maps, it is recommended to use template maps instead of uploading multiple [Named Map MapConfigs](http://docs.cartodb.com/cartodb-platform/maps-api/mapconfig/#named-map-layer-options).
MapConfig | a [Named Map MapConfig](http://docs.cartodb.com/cartodb-platform/maps-api/mapconfig/#named-map-layer-options) is required to create a Named Map
The `name` argument defines how to name this "template_name".json. Note that there are some requirements for how to name a Named Map template. See the [`name`](#arguments) argument description for details.
name | There can only be _one_ template with the same name for any user. Valid names start with a letter or a number, and only contain letters, numbers, dashes (-), or underscores (_). _This is specific to the name of your Named Map that is specified in the `name` property of the template file_.
|_ valid_tokens | when `"method"` is set to `"token"`, the values listed here allow you to instantiate the Named Map. See this [example](http://docs.cartodb.com/faqs/manipulating-your-data/#how-to-create-a-password-protected-named-map) for how to create a password-protected map.
layergroup | the layergroup configurations, as specified in the MapConfig. See [MapConfig File Format](http://docs.cartodb.com/cartodb-platform/maps-api/mapconfig/) for more information.
view (optional) | extra keys to specify the view area for the map. It can be used to have a static preview of a Named Map without having to instantiate it. It is possible to specify it with `center` + `zoom` or with a bounding box `bbox`. Center+zoom takes precedence over bounding box.
{% comment %}writer note_csobier: Carla - Regarding view (optional) How do you see a Named Map without instantiating it via CartoDB.js/createLayer, is this referring to getting tiles via xyz url? Need an example here.{% endcomment %}
Placeholders are variables that can be placed in your MapConfig template.json file. Placeholders need to be defined with a `type` and a default value for MapConfigs. See details about defining a MapConfig `type` for [Layergoup configurations](http://docs.cartodb.com/cartodb-platform/maps-api/mapconfig/#layergroup-configurations).
Valid placeholder names start with a letter and can only contain letters, numbers, or underscores. They have to be written between the `<%=` and `%>` strings in order to be replaced.
Placeholder default values will be used whenever new values are not provided as options, at the time of creation on the client. They can also be used to test the template by creating a default version with new options provided.
{% comment %}writer note_csobier: Carla - This section seems out of place. Should it come sooner or is it part of Placeholder Types? Also, why is the curl command shown here formatted differently than curl commands listed in the rest of the docs? Perhaps we can use this opportunity to ensure all curl commands in this section are correct?{% endcomment %}
The response back from the API provides the name of your MapConfig as a template, enabling you to create the Named Map details by inserting your variables into the template where placeholders are defined, and create custom queries using SQL.
Instantiating a Named Map allows you to fetch the map tiles. You can use the Maps API to instantiate, or use the CartoDB.js `createLayer()` function. The result is an Anonymous Map.
{% comment %}writer note_csobier: Carla - When do you need to instantiate a named map and when don't you? For example, you don't need to instantiate a named map with cartodb.js if you're using xyz tiles? Are there other ways to instantiate without CartoDB.js? If so, why would you?{% endcomment %}
The fields you pass as `params.json` depend on the variables allowed by the Named Map. If there are variables missing, it will raise an error (HTTP 400).
**Note:** It is required that you include a `params.json` file to instantiate a Named Map that contains variables, even if you have no fields to pass and the JSON is empty. (This is specific to when a Named Map allows variables (if placeholders were defined in the MapConfig/template.json by the user).
You can then use the `layergroupid` for fetching tiles and grids as you would normally (see [Anonymous Maps](http://docs.cartodb.com/cartodb-platform/maps-api/anonymous-maps/)).
If using a [JSONP](https://en.wikipedia.org/wiki/JSONP) (for old browsers) request, there is a special endpoint used to initialize and create a Named Map.
#### Definition
```bash
GET /api/v1/map/named/:template_name/jsonp
```
#### Params
Params | Description
--- | ---
auth_token | `"token"` or `"open"` (`"open"` is the default if no method is specified. Use `"token"` to password-protect your map)
params | Encoded JSON with the params (variables) needed for the Named Map
lmza | You can use an LZMA compressed file instead of a params JSON file
{% comment %}writer note_csobier: Carla - Michelle tested the above curl command and it did not work. Can you confirm if this is written correctly? Should it just be "=params_json" and not "=template_params_json"? Also, need you to confirm if the Response below is still correct.{% endcomment %}
This takes the `callback` function (required), `auth_token` if the template needs auth, and `config` which is the variable for the template (in cases where it has variables).
You can initialize your Named Map using CartoDB.js, by specifying a Named Map template in a [layer source object](http://docs.cartodb.com/cartodb-platform/cartodb-js/layer-source-object/#named-maps-layer-source-object-type-namedmap).
**Note:** Instantiating a Named Map over a `createLayer` does not require an API Key and by default, does not include auth tokens. _If_ you defined auth tokens for the Named Map configuration, then you will have to include them.
1. [layer.setParams()](http://docs.cartodb.com/cartodb-platform/cartodb-js/api-methods/#layersetparamskey-value) allows you to change the template variables (in the placeholders object) via JavaScript
2. [layer.setAuthToken()](http://docs.cartodb.com/cartodb-platform/cartodb-js/api-methods/#layersetauthtokenauthtoken) allows you to set the auth tokens to create the layer
Optionally, you can fetch projected tiles for your Named Map. This does not require an API Key. There are several ways to fetch XYZ tiles.
#### Get Template
If fetching XYZ tiles with the [`function getTemplate`](https://github.com/CartoDB/Windshaft-cartodb/blob/9449642773ed284d3855b08f0358c634f6634d59/lib/cartodb/controllers/named_maps_admin.js#L103) call, _it requires an auth token_.
```javascript
function getTemplate(err, authenticated) {
ifUnauthenticated(authenticated, 'Only authenticated users can get template maps');
```
#### List Templates
If fetching XYZ tiles with the [`function listTemplates`](https://github.com/CartoDB/Windshaft-cartodb/blob/9449642773ed284d3855b08f0358c634f6634d59/lib/cartodb/controllers/named_maps_admin.js#L166) call, _it requires an auth token_.
```javascript
function listTemplates(err, authenticated) {
ifUnauthenticated(authenticated, 'Only authenticated user can list templated maps');
```
#### Get Mapnik Retina Tiles
This method of fetching XYZ tiles ignores the Named Map template name and obtains the [Layergroup `srid`](http://docs.cartodb.com/cartodb-platform/maps-api/mapconfig/#layergroup-configurations) as the key value used to initialize the map. Note that it obtains the retina tiles that are not related to basemaps.
```javascript
GET (?:/api/v1/map|/user/:user/api/v1/map|/tiles/layergroup)/:token/:z/:x/:y@:scale_factor?x.:format {:user(f),:token(f),:z(f),:x(f),:y(f),:scale_factor(t),:format(f)} (1)
Notes: Mapnik retina tiles [0]
```
**Tip:** This is the code defined as "Mapnik retina tiles" in the [Windshaft-cartodb Routes list](https://github.com/CartoDB/Windshaft-cartodb/blob/723dc59490f774c680efb74ab19fa2a556c66d9d/docs/Routes.md#routes-list).
#### Fetch XYZ tiles directly
This method uses XYZ-based URLs to fetch tiles directly, and instantiates the Named Map as part of the request to your application. You do not have to do any other steps to initialize your map. This is done with the [`NamedMapsController`](https://github.com/CartoDB/Windshaft-cartodb/blob/9449642773ed284d3855b08f0358c634f6634d59/lib/cartodb/controllers/named_maps.js#L31) base url value for your app.
{% comment %}writer note_csobier: Carla - Is it true that if you're using xyz urls to get tiles, that does instantiation for you? so you don't need to do any other steps to instantiate?{% endcomment %}
