4 Replies Latest reply: May 8, 2015 5:32 PM by Martin Curtis RSS

    What Qlik Sense Map Object needs to use a Slippy map ?

    Bertrand HERARD


      Now that Qlik Sense Maps configuration is available.

      I'd like to know what is the complete (technical ?) definition of a Slippy Maps ? What Qlik sense really needs (for map object background) ?


      In a link gave by Dan English on this subject (http://wiki.openstreetmap.org/wiki/Slippy_Map), the global definition of Slippy Map is : "Slippy Map is, in general, a term referring to modern web maps which let you zoom and pan around (the map slips around when you drag the mouse)."

      I'd like to use a local GIS for map tiles in Qlik sense. with my GIS (and OpenLayers), I can display a map, and navigate or zoom in it with the mouse. (so it seems similar to the previous (functional) definition).


      But In Qlik sense help, I only find url finishing by /${z}/${x}/${y}.png. So I trying to link the functional definition and theses urls :

      Can you please tell me more about theses "/${z}/${x}/${y}.png" urls ? What do I need to develop to allow Qlik Sense to use a local GIS ? Is there an official technical definition of Slippy maps (technology, communication ...)


      Best regard

        • Re: What Qlik Sense Map Object needs to use a Slippy map ?
          Miralem Drek

          Hi Bertrand,


          A slippy map is often built up by tiles of 256x256 images which are loaded dynamically based on the current viewport of the map. The service used in the client (e.g. OpenLayers) keeps track of this for you and replaces the dynamic variables in the url (/${z}/${x}/${y}) with numbers representing a specific tile. z is for the zoom level, x/y for horizontal/vertical position (projected longitude/latitude). If you look at the network traffic when you pan and zoom around you'll see these images being fetched. There is only one image at zoom level zero (the whole world (not really due to Mercator projection)) and is then doubled at each zoom level and direction. Here's a sample tile of New York at zoom level 11, if you add +1 to the zoom level and double the x and y you'll get a closer look at the lower left of the previous image.


          So to make a slippy map work in Sense you just need the address to the Tile Map Service you're using. There are plenty of tutorials on how to set up a TMS (Dan's link is a good start for resources), which one you choose and how you set it up doesn't really matter for Sense as they are totally decoupled.


          Best regards,


          • Re: What Qlik Sense Map Object needs to use a Slippy map ?

            Which GIS are you using? Maybe it does not serve tiles in slippy map format.


            There are other services like OpenStreetMaps, CloudMade or Mapbox which serve map tiles in slippy map format.