Understand when to use tiles or features

You must decide which layers to use in your map from among the layers available to you. Each layer type provides different functionality, from rapid display to complex queries and multiuser editing. The correct type of layer effectively communicates your message in the map, can improve how quickly apps can load your map under high demand, or allows map users to contribute content.

If you have privileges to publish, you can create the types of layers that meet your needs. If not, you must find existing layers that meet your requirements. Keep the following in mind when looking for content in your groups, organization, ArcGIS Living Atlas of the World, and other sources:

• Tile layers support fast visualization of large datasets because the data is stored in predefined tile images. These layer types are often used as reference layers in maps and cannot be edited.

  If the features you want to include in your map cover a large area or are complex, using a hosted tile layer or hosted vector tile layer will decrease the time it takes to draw the features in your map. You could also use a cached imagery layer or map image layer that represents the features you need, as these layers also use predefined caches of data.

• Feature layers (as the name implies) are focused on the features and their attributes. For example, they allow you to apply different styles to the layer based on feature attributes, apply filters to the layer to display only certain features, cluster points based on common attributes, or configure pop-ups that present attribute information. If the owners enable it, you can edit the data.

  Feature layers are more flexible and interactive than tile layers, but this comes at a cost. As most feature layer functionality relies on accessing the feature attributes, the app must communicate frequently with the source data, which can slow drawing times. But, if the map you create is intended to allow people to collect or update data, or you want to filter or symbolize features based on specific attributes, you need to use a feature layer in your map.

You can use tile and feature layers in offline maps. However, the layers and your map must be enabled for offline use.

Optimize your maps for high demand

If you have a heavily used map, you will want to configure your map so it loads as quickly as possible while also conserving server resources. In most cases, using cached layers rather than dynamic layers will improve map performance using a minimum of resources. Follow these guidelines for optimizing the layers in your map to reduce the time it takes to load the map during high-demand activity.

• If you have vector data to include in the map and the data does not require frequent updates, use vector tile layers instead of feature layers in the map. Vector tile layers offer faster drawing times for large datasets. Also, the features in vector tile layers draw more clearly than those in tile layers and their caches take less time to create than tile layer caches or map service caches. In addition, you can update vector tile layers occasionally by rebuilding the cache (if the vector tile layer has an associated feature layer) or replacing the layer (if the vector tile layer was published from a vector tile package.)
• If you have imagery data to include in the map, use cached image services in the map rather than dynamic image services.
• If the data has fewer than 4,000 point features or 2,000 line or polygon features and only you need to edit it, add the data to your map as a feature collection. However, this is not an efficient way to manage data that needs to be updated frequently or needs multiple editors.
• If your data has more than 4,000 point features or 2,000 line or polygon features, or is larger than 10 MB, publish it as a hosted feature layer and ensure editing is disabled. When editing is enabled, the browser makes larger requests to include full geometry of the hosted feature layer, which makes the layer slower to draw. The layer owner, organization administrators, and members of groups with item update capability with whom you've shared the layer can open the hosted feature layer with editing enabled without having to enable editing for everyone else.
• You can export a hosted feature layer as a feature collection generalized for web display. You lose some precision but optimize the drawing speed. Exported feature collections that have been generalized for web display only work in web apps. They do not work in desktop and mobile apps.
• Remove any filters on your hosted feature layers. If it is important to manage a subset of the features as an individual layer, publish each filtered set of data as its own individual layer.

Apply different configurations to a layer

Layer owners define the properties stored with the layer, such as the title, visibility range, and style. When you find the type of layer that contains the data you need and add it to your map, you may decide you need to apply your own configurations to the layer to tailor what you present in your map. You can change many of these properties directly in the map, but what if you want to use the same layer in your map but with different styles or filters applied? In these cases, make a copy of the layer inside your map and alter the settings for each copy.

For example, you want your map to show the businesses in your downtown area. You have a single hosted feature layer that contains business locations, names, types, and information about tenancy and business licenses. You want to show different layers that represent the downtown area for different time periods. Change the style of the feature layer to use different symbols for different types of businesses. Next, make and save three copies of the layer, one for each of the following time periods, and name the copies accordingly: businesses 1900 to 1939, businesses 1940 to 1989, and businesses 1990 to present. Apply a filter to each saved copy to show the business information for those time periods. You now have three different representations of the same layer in your map.

When you copy most types of layers, your copy still references the data in the original layer. See Copy and save layers for more information on when you should make a copy only and when you should save your copy.

Apply your own style to a hosted vector tile layer

Map Viewer Classic (formerly Map Viewer) allows you to change the style of the vector tile layers in your maps. This is similar to changing the style of a feature layer in your map, as the style is applied only in that specific map.

If you want the same style to be available in other maps without having to redefine it in each map, save a copy of the layer, download the layer's style file from the layer's item page, edit the style, and update your copy of the hosted vector tile layer to use the new style.

See Update vector tile layer style for instructions on changing styles in Map Viewer Classic and links to instructions for altering a style file.

Like the copies you make to apply different configurations, the copy of a hosted vector tile layer that you save still references the original vector tiles. If the owner of the hosted vector tile layer deletes the layer or stops sharing it with you, you no longer have access to the data. Similarly, if the owner of the hosted vector tile layer replaces the layer's contents with a layer that does not include your new style, the style you defined on your copy may no longer function.