Question

I have a graph on the screen and all the data that is needed is in a variable called jsonData, this being my way to avoid a JSON-File stored seperately on a server.
Now the jsonData contains more than i really want to show at the beginning, so I have to select the needed nodes.
The idea is to have a root node and show all the nodes directly connected with it and the conections between them.
Is there any simple possibility to do this?
Maybe I can change the line

var node = svg.selectAll(".node")
  .data(jsonData.nodes)
.enter().append("g")
  .attr("class", "node")
  .call(force.drag);

because it doesn’t need to select all of them, but how can I pick the ones needed?
I have an array in the background that contains all the needed links and I’m up to writing a part that will store the connected nodes.
I can’t give this new array directly to the svg.selectAll-part because otherwise the links will crash (they refer to the number of the node by it’s original position in the bigger array).
Any hints on that? I couldn’t find any examples for this on via Google-research, but if you can spot something out there in the net, just feel free to answer with the link!

Thanks in advance,
David

Answer 1

function getNodesIndex(searchedFor){
    for(var i = 0; i < jsonData.nodes.length; i++){
        if(jsonData.nodes[i].name == searchedFor){
            return i;   
        }
    }//for
}

function getNetParts(searchedFor){
    reqNodes = null;
    reqNodes = [];
    reqLinks = null;
    reqLinks = [];

    var index = getNodesIndex(searchedFor);
    reqNodes.push(jsonData.nodes[index]);   

    for(var y = 0; y < jsonData.nodes[index].connections.length; y++){
        //stores every node connected with the main node in reqNode
        reqNodes.push(jsonData.nodes[jsonData.nodes[index].connections[y]]);    
    }

    for(var z = 1; z < reqNodes.length; z++){                   
        //circle through stored Nodes
        for(var c = 0; c < reqNodes[z].connections.length; c++){    
            //inspect all of their connections
            for(var w = 0; w < reqNodes.length; w++){
                //check all stored reqNodes for the one linked
                if(jsonData.nodes[reqNodes[z].connections[c]].name == reqNodes[w].name)           { 
                    //the node is available at reqNodes?
                    var source = null; 
                    var newLink = {
                        "source":z,
                        "target":w,
                        "value":1,
                    };                          
                    reqLinks.push(newLink);                 
                }
            }   
        }   
    }
}

And then update() just deletes anything on the screen, gets the new data and rebuilds the visualisation.
Just in case anyone has the same trouble… 😉