Rendering gets slower with increasing number and complexity of geometries, and complexity styling.
#Maptiler no html download
Depending on the complexity of the data, initial download times of the XML that contains the vector data and styles can be long. A smart native technique for rendering small amounts of vector data is the HTML (Scalable Vector Graphics) element.Interactivity like style changes and querying requires additional data transfers, because all rendering happens on the server. Download times increase with map size and screen resolution. Mutliple elements can be stitched together from tiles.
Using CSS, images can be translated, scaled and rotated to respond to user interactions.
The feature list of the OpenLayers library above shows it already: different techniques are available for loading and rendering map data in the browser, and there is a tradeoff for speed in download versus speed in rendering. Options for rendering graphics in the browser This means that not only attributes that are included in the data and the current view resolution can be used for rule-based styling, but any information from the application state. Vector data can be styled on the client with JavaScript functions. It supports raster and vector data in various formats, with static, tiled, and extent based fetching strategies. Interactive maps, where users can pan and zoom to any place in the world, have two bottlenecks when it comes to providing a smooth user experience: downloading data for the region of interest, and rendering it.Ī popular and very flexible mapping library is OpenLayers. So instead of relying on native browser optimisations, we need mapping libraries that provide the user interface and use DOM- and JavaScript based APIs for loading, parsing and rendering of map data. And still, unlike with pictures or videos, there is no HTML or element for inserting a map in a web page. Interactive maps have become very popular elements on web pages, and are key in applications that deal with geospatial information. In this post, I am going to show how rendering performance in OpenLayers could benefit from OffscreenCanvas. Unfortunately it is not widely supported in mainstream browsers. There is a new browser technology, OffscreenCanvas, which allows rendering in web workers that run in parallel to the main thread. Performance is usually good, but there are corner cases where the user experience is negatively affected by an unresponsive user interface. ~ Amelia Bellamy-Royds, Maps for HTML CG co-chair SummaryĪs an active developer of the OpenLayers mapping library, I have been working a lot on performance improvements in the rendering pipeline. Andreas’ results give a taste of the performance improvements that a browser-optimized rendering pathway could achieve. This article by Andreas Hocevar describes the use of a new web platform feature, OffscreenCanvas, within a JS-based web map framework, to move graphics rendering to a separate thread. And until recently, it wasn’t even possible for web map frameworks to recreate some of these optimizations with JavaScript. Maps on the Web don’t currently benefit from any special optimizations, since the browser has no way of understanding what map content is or how users interact with it. With built-in declarative content (that is, content defined using markup elements or CSS properties), browsers can implement a lot of performance improvements, such as pre-loading or lazy-loading content, and drawing or animating graphics in separate threads. But we also care about making web maps better right now, in a Web that relies on JavaScript-based maps in HTML. Osgearth tutorial.The work of the Maps for HTML community group primarily focuses on proposals for new web standards for map viewers that would be built in to the browser.
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