The zoom values of a vector tile layer are equivalent to the zoom values of an image tile layer minus one. Vector tile layers and image tile layers both support zoom levels, but they use different scale values for each preset. The scale of each zoom level preset (0-23) depends on the type of layer used in your application. To learn more about zoom level values and tile widths, go to the Zoom levels page on the OpenStreetMap Wiki. They do this despite using vector tiles and vector data, which means they don't need to lock to these specific legacy zoom levels for a crisp map display that avoids pixel resampling, although many do.ĪrcGIS APIs can render many different map projections at a full range of scales, and so use scale rather than zoom level (although the ArcGIS JavaScript API does provide support for zoom levels as a convenience). Many modern mapping solutions and APIs only display Web Mercator maps and so continue to use zoom level as a shortcut for map scale. Over time, this mapping between zoom levels and map scales became established as a de facto standard, despite tiles being used outside of browser apps at many different screen resolutions, and despite the onset of dynamically rendered vector tiles in place of the original pre-rendered 96 ppi PNG or JPEG image tiles. Web browsers used the standard CSS pixel size of 96 ppi: that is, 1 tile pixel would match 1 screen (browser) pixel. By the time you get to zoom level 20, 1,099,511,627,776 tiles are needed.Ĭrucially, these zoom levels represented scales at which the pre-rendered 96 ppi 256x256 pixel map tiles could be displayed crisply, without pixel resampling, in a web browser. Zoom level 1 requires 4 tiles to cover the same geographic area as the single zoom level 0 tile zoom level 2 requires 16 tiles zoom level 3 requires 64, and so on. Zooming in by one level halves the scale (and consequently quadruples the number of 256x256 pixel tiles required to cover the world - 2x the horizontal tiles, and 2x the vertical tiles). So 591657527.591555 is the map scale for zoom level 0.įigure 1: A typical 256x256 pixel, 96 ppi, zoom level 0 image tile. This single tile, spanning -180º longitude to 180º longitude at 256 pixels width and 96 ppi, turns out to be of horizontal scale 1:591,657,527.591555 at the equator. The tiling scheme is based on pre-rendering sets of 96 ppi 256x256 pixel PNG or JPEG image tiles, starting with a single tile at zoom level 0 that covers the entire world. These adopted a tiling scheme that defined how a global map in Web Mercator projection could be pre-rendered for display in a web browser. This one has smoothing for when you focus on an object or adjust the zoom level.Zoom levels were made popular by various web mapping solutions and APIs in the early 2000s. View world/action from top at some angle. fast move (holding Shift button for example).Rotate and Tilt (can disable these and limit tilt's min/max).Pan up/down/left/right (can disable by not binding related input).Freely move camera (with or without holding a button).This is a simpler version of the TopDownCamera. Fast move (holding Shift button for example).
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