![]() ![]() Benefits include, image comparison, map merging, and masking effects. By providing an interactive tool to control level of opacity on tiles, the cartographer can effectively combine two views. A significant disadvantage of tiled overlays is that they totally obscure the underlying base map. By enabling the presentation of more targeted map information, such overlays are an increasingly important method of map presentation through the Internet. A multilevel overlay can be created by tiling several different maps or orthophotos. ![]() Any digital map whether a scanned historic one or a computer-generated thematic map can be converted to tiles. User-generated tiles can be overlayed on top of these maps, obscuring the standard map or satellite views. This online method of map distribution was introduced by Google in 2005 and all the major online-mapping services including Bing, Yahoo, OpenStreetMap, Nokia, and MapQuest have since adopted the technique. Splitting maps into small contiguous tiles increases the speed of Internet map distribution, improves the panning of the map, and facilitates the presentation at multiple scales. The browser applies the plan oblique transformation, computes a shaded relief, and texturizes the terrain with tiled map layers. The second method uses a tiled digital terrain model that is loaded by the web browser. The second method renders plan oblique relief on-the-fly in a web browser using WebGL and a customized version of OpenLayers 3, which enables users to select arbitrary terrain inclination and map rotation angles. The tiles are visualized with a standard web mapping framework. The first method pre-renders plan oblique tiles with a server-side application. The goal is to allow users to adjust the terrain inclination and map rotation angles to better visualize the third dimension of the terrain. This article introduces two complementary methods that address these issues by using the 3D graphics pipeline to render plan oblique relief for tile-based web maps. Existing plan oblique maps are static: the angle of terrain inclination is not adjustable and the orientation of plan oblique inclination does not change with the orientation of the map. Plan oblique relief shows terrain with a side view on a two-dimensional map, resulting in visualizations where the third dimension of the terrain is more explicit than on traditional two-dimensional maps. Generally, the WebP format downloaded about three times fewer data than Portable Network Graphics (PNG). More data, but only one or two tiles, were downloaded for vector tiles in zoom and move interactions, while 40 tiles were downloaded for raster tiles for the same interactions. The observed results provide a comprehensive comparison according to specific interactions. ![]() ![]() Based on eight pilot studies, performance testing on loading time, data size, and the number of requests were performed. This method simplifies changing symbology or topology. Only vector geometry is stored on the server, while symbology, rendering, and defining zoom levels run on the client-side. This method has a few disadvantages: if any change in the dataset is required, the entire tile-generating process must be redone. All tiles are generated according to a standardized scheme. The concept behind raster tiles is based on pre-generating an original dataset including a customized symbology and style. This article describes an experiment to test both raster and vector tile methods. Raster tiles are currently considered as a regular solution, while the use of vector tiles is becoming more widespread. Recent developments in web map applications have widely affected how background maps are rendered. ![]()
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