Zoom levels and scale

A zoom level or scale is a number that defines how large or small the contents of a map appear in a map view.

  • Scale is a ratio between measurements on a map view and measurements in the real-world. When a map is displayed at a scale of 1:100 (or simply 100.0), 1cm on the display represents 1m (100cm) in the real world. A scale of 100,000.0 means that 1cm on the map display represents 1km (100,000cm) in the real world, and so on.
  • Zoom level is a number between 0 (global view) and 23 (very detailed view) and is used as a shorthand for predetermined scale values, but comes with some limitations.

Most web mapping APIs support zoom levels as a convenience. Zoom levels are only typically used for building applications that display data in Web Mercator projection. Scales are used to display data in any projection.

Zoom level presets

The scale of each zoom level preset (0-23) depends on the type of layer used in your application. Vector tile layers and image tile layers both support zoom levels, but they use different scale values for each preset.

The zoom values of a vector tile layer are equivalent to the zoom values of an map tile layer minus one. For example, a zoom level of 1 on an map tile layer corresponds to a zoom level of 0 on a vector tile layer (scale 1 : 295828763).

  • A zoom level of 0 for an map tile layer (scale 1 : 591657527) corresponds to a zoom level of -1 for a vector tile layer. Since the minimum zoom level is 0, this scale preset does not exist for vector tile layers.

  • Conversely, a zoom level of 23 for vector tile layers (scale 1 : 35.2655368) corresponds to a zoom level of 24 for image tile layers. Since the maximum zoom level is 23, this scale preset does not exist for image tile layers.

If there is no zoom level preset corresponding to your desired scale, you can instead set the map scale directly. The method for doing this depends on the API or tool you are using.

Basemap layers

The basemap styles service provides basemaps with layers formatted as either map tile layers or vector tile layers. When you use a basemap in your application, the scale of your zoom level will vary based on the type of layer the basemap uses.

To learn if a basemap uses vector tile layers or image tile layers, go to its item page in ArcGIS Online from the World Basemaps for Developers group.

Conversion tool

Use this interactive tool to translate zoom levels to map scales:

Zoom level to scale converter

Adjust the range slider to convert zoom level presets to their corresponding map scales.

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