Map visualisation


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HSLayers (Help Service + OpenLayers) combines capabilities of ExtJS and OpenLayers and several helping scripts to establish truly Web GIS applications. Development started in 2007. In 2009, after 2 years of development, it was released under conditions of GNU General Public License 3.

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Map visualisation

  1. 1. Map visualisation = HSLayers Introduction OpenLayers is a JavaScript toolkit for creating of mapping applications in the web browsers. OpenLayers is more powerful than Google Maps toolkit. It has abilities for showing maps based on various raster and vector formats. It has connectors to many standards and quasi-standards such as MapServer, OGC Web Mapping Service, ArcIMS, simple Image layer, GML, GeoRSS, KML, Text and others and Google, Yahoo and VirtualEarth for commercial data providers. The user – creator of mapping application – does not need to take care about differences between various web browsers and their JavaScript implementation or between various data formats. ExtJS is a multi-browser JavaScript library for building of rich internet applications. It consists from customizable User Interface widgets, ready to be used by designers of Graphical User Interface, similar to desktop widgets, which among others are text field and text area input controls, date fields with a pop-up date-picker, numeric fields, list box, radio and checkbox buttons, wysiwyg html editor, text grids, suitable for spreadsheets, trees, tab panels, toolbars, menus and sliders. ExtJS was originally built as an add-on library extension of Yahoo UI, but now it is the standalone project. HSLayers features are coming up from OpenLayers and therefore their characteristics are as follows: • Portrayal of various types of data: • Raster: OGC WMS(-T), Image (PNG, JPEG, GIF), … • Vector: OGC WFS(-T), GML, GeoRSS, KML, GPX, GeoJSON, … • Data sources from commercial servers: Google Maps, Virtual Earth, Yahoo Maps, … • The user interface (use control) adheres to current conventions in web map portals. • Information about queried objects in text bubbles. • HSLayers additional functions: • Dynamic adding of OGC (Open Geospatial Consortium) services into map - clients for WMS and WFS • Portrayal of independent data sources on the client side. Map composition is composed on the basis of requests to various servers. It is thus not necessary to install a map server. • Saving of map composition according to WMC (Web Map Context) OGC specification on user computer for repeated future use or for sharing between users. • Extension of compute functions based on WPS (Web Processing Service) OGC service - according to user needs • Multilingual environment • Map requests to various types of data stored on various servers, with automatic processing of results
  2. 2. • Work with micro-formats • Search on the map • Connection of the application with catalogue client (OGC CSW) in the geoportal, which enables display of the searched service from catalogue directly on the map. • Edit function - snapping to chosen layers • Possibilities for advanced configuration of user requests • Advanced measuring of length and surfaces • Print of map compositions - possibility of large print outs (up to A0 format), user configuration of print settings Work with HSlayers HSlayers client application is divided into three independent parts: • Map panel • Management panel
  3. 3. • Tools box • Map panel Map panel displays maps, but also contain buttons for working with maps. The zooming, moving, queering and measurement in maps is supported by functions related to single buttons in window. • Moving button support moving wit maps on left, right, up and down and display all maps (clicking on globe) • Zoom button supports zooming in or our Komentář [LU1]: ?
  4. 4. • Hands button allows to move with maps using left mouse button. Left mouse button together with CTRL allow select map window for visualisation • Distance measure button allows measuring of distances in maps clicking on map. Information about distances is visible in Management panel in Info layer. Measurement is finished by double click • • Area measurement button allows measuring of areas in maps clicking on map. Information about areas is visible in Management panel in Info layer. Measurement is finished by double click • • Info button allows you query objects in the map (including WMS services). You can ask by clicking in single point or using rectangle (CTRL + left mouse button). Information is visible in Management panel in Info layer • • Pin button allows you to put point of interests into map • ¨ • Part of Map window is also information about scale and actual coordinates
  5. 5. Management panel Management panel contains for bookmarks : • Layers • Info • OWS • Print Layers bookmark Pushing layers bookmarks you can switch on or of single layers in map composition. Clicking by right button on selected layer you can change transparency of selected layer or remove layer from composition
  6. 6. Clicking on you can display legends of layers in composition (including WMS and WFS if it is available) Clicking on you will restore initial composition (see also OWS bookmark). Info bookmark Info bookmark open you Info panel, which is passive panel. It is used by measurement functionalities and info functionalities of Map window. OWS bookmark OWS bookmark support adding of new layers into Map Window using Web Mapping Services or Web Feature services
  7. 7. After editing URL address (this address could also be fulfilled using catalogue services see next chapter) and pushing button Connect get capabilities of selected service will be displayed Selecting of layers and pushing button to Map the selected layers will be added into list of layers and displayed in Map window.
  8. 8. For WMS services there are additional functionalities
  9. 9. You can define image format for WMS services based on get capabilities of services
  10. 10. You can define query format for selected WMS And you can selected from available coordinate systems list for selected services
  11. 11. AT least you can also select, if tile caching will be used for this WMS
  12. 12. Print bookmark Print bookmark support printing of selected map composition into pdf file. For printing could be defined description of map and additional text, paper format
  13. 13. Scale And you can also define, if printing will have portrait or landscape format
  14. 14. Pushing button print pdf map is printed according defined parameters Tools box Tool box support next functions: • Button Load allows to add into existing map composition additional levels stored in xml file on the hardisckm which describe map composition according Web Map Content (WMC) standard, to use visualisation parameters from WMC and also switch cut out defined Komentář [LU2]: ?
  15. 15. in WMC file. • • • Button Save allows to store WMC of currently used WMS in Maps and current cut out and visualisation parameters as WMC • Button previous will switch on previous cut out • • Button next will switch on next cut out
  16. 16. • Rollout menu supports selection of projection parameters for visualisation • Button permanent link after clicking of right mouse button allows you to copy URL of current map window