CODEWITHSUNDEEP
javaperformanceprocessing
NightMarcher
NightMarcher

Reputation: 159

Filtering Data in Java/Processing

I am working on a map based data visualization project that scrapes data from an XML file. Locations are placed on a map based on geo location and locations are interactive with mouse clicks that will then display information about the location. I need to start filtering the results based on information about each location. Ex: lets say the i want to display information about trees and i know their location and their type. I would want to filter in and out walnut, cherry, oak using check boxes. I am trying to plan out how to attack this problem from a design standpoint. Currently the all information is pulled directly from the XML file with very little going into new Arrays/Lists. Any recommendations as I am trying to conquer this task? If you need me to elaborate more or want any more information please let me know.

EDIT: I'm sorry if this is vague, I'm not entirely sure how to ask the question. So right now I am taking 311 data and putting information into Array's based on the information I want to display. So lets say I want get an address. (At this point a map has been populated with all of the individual locations from the 311 data lets say 200 spots) I click one location, and that location is tied to an index in an array that has all of the addresses. So at any time I can use an index to get information from an array. There are multiple arrays holding information like address, report type, time, etc. I want the locations on the map to be sorted by the report type. I hope this makes more sense.

Upvotes: 0

Views: 242

Answers (2)

v.k.
v.k.

Reputation: 2854

Are you using processing tag for Processing.org right? If I understand you, isn't the case of make an object that group all data relative to one location, and when needed retrieve the info using a getter or even dot notation? I though of something like:

class Local(){
String name;
String address;
//whatever else...
float mapPosX, mapPosY;


boolean ispressedOver(){
//return if mouse over
}

}

create Locals using XML data, store in an array of Local, and when mouse pressed get it

if (localsArray[i].isPressedOver){display(localsArray[i].address);}

this would be a very simple example of the idea except for the xml parsing to an 

Place[] places  = new Place[4];


void setup() {
  size(600, 400);
  noStroke();
  places[0] = new Place ("one", "That street, 12 - BR", 0.32044, 0.230098, 200, 98);
  places[1] = new Place ("two", "This street, 35 - UG", 0.22222, 0.084723, 394,176);
  places[2] = new Place ("three", "Other street, 132 - TY", 0.32321, 0.36388, 157, 283);
  places[3] = new Place ("four", "Principal street, 672 - OP", 0.909044, 0.7828939, 276, 312);
}

void draw() {
  background(75, 16, 160);
  for(Place p:places){
  p.display();
  }
}

class Place {
  String name;
  String address;
  float latitude;
  float longitude;
  float xPos;
  float yPos;
  float sz = 40;

  Place(String n, String a, float lat, float lng, float x, float y) {

    name      = n;
    address   = a;
    latitude  = lat;
    longitude = lng;
    xPos      = x;
    yPos      = y;
  }

  void display() {

    fill(200, 210, 100);
    rect(xPos, yPos, sz, sz);

    if (isOver()) {
      String quick = name + " - " + address + " - " + latitude + " - " + longitude ;
      fill(0);
      text(quick, xPos - textWidth(quick)/2, yPos - 10);
    }
  }

  boolean isOver() {
    return (mouseX > xPos && mouseX < xPos + sz && mouseY > yPos && mouseY < yPos + sz);
  }
}

In following link I pasted a code I'm working on. It is not displaying anything. But I does get XML data and build objects based on them. For now the output is in the console. I don't know if is going to help much. Most variables names are in portuguese :P And it is not commented... But it works. You can run it. it gets the xml from an API in the web. There are two classes, don't bother with Query. It is necessary to get the xml, but not related to your question. The Prop class is the data holder. It gets an xml as parameter and parse it's fields to member vars. For now there is only one method. toString() used to display data to the console.

http://pastebin.com/8gGDsFAv

Upvotes: 0

Guy Gavriely
Guy Gavriely

Reputation: 11396

I hope I understand correctly, this seem like a regular data management system requirements, it will be hard to cover these kind of systems in a few words, but in a nutshell I'd say that those systems are divided into layers:

  1. data layer, usually some database, try to install and use a database like mysql
  2. data access layer, I understand you're using java, consider using hibernate that will let you describe and use your database using objects rather than RDBMS tables, here you would also have sql / hql queries
  3. some business layer to have the logic on top of these dummy data objects, or maybe connect to some external service
  4. serve this data to you client, whatever it runs on, if its a Java client or a web browser

Check out java spring http://projects.spring.io/spring-framework/ on how its done in practice.

Then, if you feel like going back and forth to the server for more data is too much on performance you may decide to cache some of the information in the client side.

Last, always remember Donald Knuth saying

about 97% of the time: premature optimization is the root of all evil.

Upvotes: 1

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