function select(buttonId) {
  document.getElementById("hand_b").className="unselected";
  document.getElementById("shape_b").className="unselected";
  document.getElementById("line_b").className="unselected";
  document.getElementById(buttonId).className="selected";
}

function stopEditing() {
  select("hand_b");
}

function getColor(named) {
  return COLORS[(colorIndex_++) % COLORS.length][named ? 0 : 1];
}


function startShape() {
  select("shape_b");
  var color = getColor(false);
  var polygon = new GPolygon([], color, 2, 0.7, color, 0.2);
  startDrawing(polygon, "Shape " + (++shapeCounter_), function() {
    var cell = this;
    var area = polygon.getArea();
    cell.innerHTML = (Math.round(area / 10000) / 100) + " km<sup>2</sup>";
  }, color,2);
}

function startLine() {
  select("line_b");
  var color = getColor(false);
  var line = new GPolyline([], color);
  startDrawing(line, "Line " + (++lineCounter_), function() {
    var cell = this;
    var len = line.getLength();
    cell.innerHTML = (Math.round(len / 10) / 100) + " km";
  }, color,1);
}

function addFeatureEntry(name, color) {
  currentRow_ = document.createElement("tr");
  var colorCell = document.createElement("td");
  currentRow_.appendChild(colorCell);
  colorCell.style.backgroundColor = color;
  colorCell.style.width = "1em";
  var nameCell = document.createElement("td");
  nameCell.setAttribute("width","70");
  currentRow_.appendChild(nameCell);
  nameCell.innerHTML = name;
  descriptionCell = document.createElement("td");
  currentRow_.appendChild(descriptionCell);
  featureTable_.appendChild(currentRow_);
  return {desc: descriptionCell, color: colorCell};
}

function startDrawing(poly, name, onUpdate, color, type) {
  measureLayers[measurelayerID] = new Array(2);
  measureLayers[measurelayerID][0] = poly; 
  measureLayers[measurelayerID][1] = 0; //temp layer
  mapID.addOverlay(measureLayers[measurelayerID][0]); 
  measurelayerID++;   
  poly.enableDrawing(options);
  poly.enableEditing({onEvent: "mouseover"});
  poly.disableEditing({onEvent: "mouseout"});
  GEvent.addListener(poly, "endline", function() {
    select("hand_b");    
    var cells = addFeatureEntry(name, color);
    if (type == 1) {
    	ntxt = (Math.round(poly.getLength() / 10) / 100) + " km";
    	descriptionCell.innerHTML = ntxt;
    }
    GEvent.bind(poly, "lineupdated", cells.desc, onUpdate);
    GEvent.addListener(poly, "click", function(latlng, index) {
      if (typeof index == "number") {
        poly.deleteVertex(index);
      } else {
        var newColor = getColor(false);
        cells.color.style.backgroundColor = newColor
        poly.setStrokeStyle({color: newColor, weight: 4});
      }
    });
  });
}