Display real-time vehicle tracks

/*************************************** *****************/
// Function: Display real-time vehicle tracks
/*************************************** ****************/

VaR trackrealtimeiconurl = "./app_themes/vehicles/carrun"; // default vehicle icon
VaR tracklasticonurl;
VaR trackrealtimerecordnum = 0;
VaR trackpoint; // location displayed on the map
VaR trackmap; // map obtained separately
VaR trackpointgroup; // set of points on the map
VaR lastresult; // The data received last time
VaR trackline; // trajectory line

// Obtain the map object
Trackmap = $ find ("trackrealtimemap ");
If (trackmap! = NULL)
{
Spatialreference = trackmap. get_spatialreference ();
Trackmap. add_zoomcompleted (function () {trackmap. refreshgraphics (true )});
Trackmap. add_pancompleted (function () {trackmap. refreshgraphics (true )});
}

// Obtain the map coordinate system
VaR spatialreference;
If (trackmap! = NULL)
Spatialreference = trackmap. get_spatialreference ();

// Extjs used here, that is, after the page content is fully loaded, execute thisCode
Ext. onready (function (){
// Process the data transmitted from the page
Processtrackrealtimeinfo (passinfo );
// Start real-time data acquisition in five seconds
SetTimeout (FIG, 5000 );
});

// Real-time Data Acquisition Function
Function gettrackrealtimeinfo ()
{
// The exejs Ajax solution is used here. You can use the Asp.net Ajax solution.
Coolite. ajaxmethods. getgpsinfo (tracktmlid, tracklasttime, {success: processtrackrealtimeinfo}); // Ajax Method
SetTimeout (gettrackrealtimeinfo, 10000); // call cyclically. The interval is 10 seconds.
}

// Process the acquired data in real time
Function processtrackrealtimeinfo (result)
{
If (result. Updated = 1) // The retrieved data is updated before processing.
{
Tracklasttime = result. gpstime; // you can specify the time for the next query.
If (lastresult! = NULL) // determine whether the current data coordinate is the same as the previous data coordinate.
{
If (result. speed = 0 & lastresult. speed = 0)
{
// Do not update the map or do anything
}
Else
{
If (lastresult. Lon! = Result. Lon | lastresult. LAT! = Result. LAT)
{
Updategpsposition (result); // draw on the map
}
}
}
Else
{
Updategpsposition (result); // draw on the map
}
Lastresult = result;
}
}

// Update the display of GPS data on the map
Function updategpsposition (result)
{
// First, determine whether there is any,
If (trackmap = NULL)
{
Trackmap = $ find ("trackrealtimemap ");
If (trackmap = NULL)
Return;
Spatialreference = trackmap. get_spatialreference ();
Trackmap. add_zoomcompleted (function () {trackmap. refreshgraphics (true )});
Trackmap. add_pancompleted (function () {trackmap. refreshgraphics (true )});
}

If (trackpoint = NULL) // create a GPS point if the GPS point does not exist. Otherwise, only update it.
{
// Add
Inittrackpointgroup ();
Createtrackpoint (result );
}
Else
{
Updatetrackpoint (result); // update location and attribute information
}
Updatetrackline (result); // updates the track line
// When the current GPS position is out of the field of view, move it to the center of the map
VaR trackmapenvelope = trackmap. get_extent ();
If (result. Lon <trackmapenvelope. get_xmin () |
Result. Lon> trackmapenvelope. get_xmax () |
Result. LAT <trackmapenvelope. get_ymin () |
Result. LAT> trackmapenvelope. get_ymax ())
{
VaR Pt = new ESRI. ADF. geometries. Point (result. Lon, result. Lat, spatialreference );
Trackmap. Panto (PT, true );
}


// Force re-draw the graphicfeature drawn on the map
Trackmap. refreshgraphics (true );
}

// Create a point on the map and set the map's field of view
Function createtrackpoint (gpsinfo)
{
Trackpointgroup. Clear ();
Trackmap. refreshgraphics (true );
VaR carurl = getcaricondirect (trackrealtimeiconurl, gpsinfo. Direction );
Tracklasticonurl = carurl;
VaR carpoint = new ESRI. ADF. geometries. Point (gpsinfo. Lon, gpsinfo. Lat, spatialreference );
VaR carmarkersymbol = new ESRI. ADF. Graphics. markersymbol (carurl, "Pointer"); // displays the conformity when an unselected state is created.

Trackpoint = $ create (ESRI. ADF. Graphics. graphicfeature, {"Geometry": carpoint, // create graphicfeature and add it to graphicsfeaturegroup
"Symbol": carmarkersymbol });

Trackpointgroup. Add (trackpoint );
Trackmap. Zoom (trackmap. get_minzoom (), carpoint, false );
Trackmap. Zoom (150, carpoint, false); // 250trackmap. get_maxzoom ()
Binit = true;
}

// Update the vertex Information
Function updatetrackpoint (gpsinfo)
{
Trackmap. refreshgraphics (true );

// Obtain the value of each object
VaR carurl = getcaricondirect (trackrealtimeiconurl, gpsinfo. Direction );
// Update coordinate information
VaR Pt = new ESRI. ADF. geometries. Point (gpsinfo. Lon, gpsinfo. Lat, spatialreference );
Trackpoint. set_geometry (PT );
If (carurl! = Tracklasticonurl)
{
Trackpoint. get_symbol (). set_imageurl (carurl); // update the image display.
Tracklasticonurl = carurl;
}
Trackmap. refreshgraphics (true );
}

// Update the track line
Function updatetrackline (gpsinfo)
{
If (lastresult = NULL) // if no data exists last time, it indicates that only one data point is uploaded, and a line cannot be created at only one point.
Return;

VaR newpath = new ESRI. ADF. geometries. coordinatecollection ();
VaR newpt = new ESRI. ADF. geometries. Point (gpsinfo. Lon, gpsinfo. Lat, spatialreference );
VaR lastpt = new ESRI. ADF. geometries. Point (lastresult. Lon, lastresult. Lat, spatialreference );
Newpath. Add (lastpt );
Newpath. Add (newpt );
If (trackline! = NULL) // If a trajectory exists, only its coordinates are updated.
{
Trackline. get_geometry (). addpath (newpath );
}
Else
{// Create a line if it does not exist
VaR newpolyline = new ESRI. ADF. geometries. polyline (newpath, spatialreference );
VaR tracklinesymbol = new ESRI. ADF. Graphics. linesymbol ();
Tracklinesymbol. set_linecolor ('blue ');
Tracklinesymbol. set_width (3 );
Tracklinesymbol. set_cursor ('crosshair ');
Tracklinesymbol. set_opacity (0.7 );
Trackline = $ create (ESRI. ADF. Graphics. graphicfeature, {"ID": trackrealtimerecordnum. tostring (),
"Geometry": newpolyline,
"Symbol": tracklinesymbol });

Trackmap. addgraphic (trackline );
}

Trackmap. refreshgraphics (true );
}

// Initialize graphicfeaturegroup
Function inittrackpointgroup ()
{
If (trackpointgroup = NULL)
{
// Use ASP. NET Ajax $ create to create a new graphic feature group and define type, properties, events.
Trackpointgroup = $ create (ESRI. ADF. Graphics. graphicfeaturegroup, {"ID": "trackpointgroup"}); //, "maptips": maptips

// Add the graphic feature group to the map.
Trackmap. addgraphic (trackpointgroup );
}
}