Updated cesium integration (markdown)

cesium-integration.md

@@ -6,7 +6,7 @@ Idea: A vector on the 2D map displays the view point and the view direction:
 
 See example with OpenLayers 2 and Google Earth plugin: http://plan.epfl.ch/?lang=en, click in the right menu on 3d. 2D and 3D are snychronized. 
 
-Question: How do get the same control feeling when manipulating the Ol3 view / the Cesium view?
+Question: How to get the same control feeling when manipulating the Ol3 view / the Cesium view?
 Uses cases are: stacked views or separated views like for EPFL.
 
 ## Smooth transition between 2d and 3d
@@ -20,7 +20,8 @@ Ongoing work:
 
 Remarks:
 * all directions must be handled (not just NS and EW);
-* all tilted situations must be handled (starting from an arbitrary tilted angle).
+* all tilted situations must be handled (starting from an arbitrary tilted angle);
+* always keep center of bottom line fixed in general, whole line for NS and EW.
 
 ## Sync raster data sources
 Idea: If a user adds a WMS/TMS/WMTS layer to ol3.js map it should also be added to the cesium globe.
@@ -67,5 +68,5 @@ This integration is developed in an open source layer built ontop of ol3js as ol
  * disable rendering of the underlying map or globe if it's hidden by the overlayed one
  * still preserve context synchronization
 * Smooth transition needs to know the elevation of the destination point of the camera
- * cesium provides an asynchronous method
+ * cesium provides an asynchronous method, synchronous planned for August
  * cesium provides in a dev branch a specific method. TDB: WHERE?