3D visual interactive analysis with myVR SDK

Recent weeks I have been working on the concept code named ‘Impact IN’  where I could apply few interesting ideas of the modern, interactive 3D  geospatial analysis. The core 3D functionality and viewshed analysis is provided by myVR SDK . While this concept is demonstrated  on iPad Pro with iOS , myVR SDK  is truly multi-platform SDK so this can be run on any platform (Android, Web, Desktop, it runs even on Daqri helmet!). I have used Apple Pencil to navigate directional viewshed and to drive fly-through on 3D map  – it works like joystick. Another concept  shown here is the real-time transition of the analysis from 3D to 2D – so while user interacts with the viewshed on 3D city model  of London , it is at the same time reflected on 2D map, creating thematic map of the impacted areas – a classic GIS result that can undergo further analysis in a GIS system of choice, or better go directly as input into the Smart M.App    (e.g. into Studio or Grid Analysis)….  following video is what attendees could see at HxGN Live 2017 . [will continue next time]

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Drawing Shape File on MapKit

Simple & strightforward test of loading shape file and drawing it on MapKit on iOS8 using drawMapRect

GitHub:https://github.com/Sumbera/SHPonMapKit

 

  • draws only polygons so far
  • primitive optimization, no scale optimisation

Reading of shape file is performed by shapelib

//------------------------------------------------------------
NS_INLINE NSArray *getPolygonsFromShapeFile(NSString *shpFilePath){
   
    const char *path = [shpFilePath cStringUsingEncoding:NSUTF8StringEncoding];
    SHPHandle shp = SHPOpen(path, "rb");
    int numEntities;
    int shapeType;
    
    SHPGetInfo(shp, &numEntities, &shapeType, NULL, NULL);
    
    NSMutableArray *allPolygons = [[NSMutableArray alloc]init];
    for (int i=0; i<numEntities; i++){
       SHPObject *shpObject = SHPReadObject(shp, i);
       if (shpObject->nSHPType == SHPT_POLYGON ||
           shpObject->nSHPType == SHPT_POLYGONZ ||
           shpObject->nSHPType == SHPT_POLYGONM){

        
            int numParts = shpObject->nParts;
            int totalVertexCount = shpObject->nVertices;

            for (int n=0; n<numParts; n++)
            {
                int startVertex = shpObject->panPartStart[n];
                int partVertexCount = (n == numParts - 1) ? totalVertexCount - startVertex : shpObject->panPartStart[n+1] - startVertex;
                int endIndex = startVertex + partVertexCount;
                
                CLLocationCoordinate2D coords[partVertexCount];
                for (int pv = startVertex, i = 0; pv < endIndex; pv++,i++) {
                    coords[i] =CLLocationCoordinate2DMake(shpObject->padfY[pv],
                                                          shpObject->padfX[pv]);
                }
                // -- this actually converts lat lon to mkmappoints projection
                MKPolygon *singlePolygon = [MKPolygon polygonWithCoordinates:coords count:partVertexCount];
                [allPolygons addObject:singlePolygon];
            }
       }
       
     SHPDestroyObject(shpObject);
       
  }
    SHPClose(shp);
    
    return [allPolygons copy];
}

credits/inspiration:

drawing : http://stackoverflow.com/questions/17673410/mkmapview-with-multiple-overlays-memory-issue
parsing : http://www.al-tyus.com/blog/2013/10/14/mapkit-and-esri-shapefiles
shapelib: http://shapelib.maptools.org
dala: http://www.geoportalpraha.cz