I am working on a map based system for a control centre. The operatives who work in the control centre work on various map based events such as traffic, roadworks etc.

One of the tasks the users wish to perform is the re-locating of events, should they move for whatever reason. There are a number of ways we can allow users to re-plot icons on the map:

Drag and drop

This is the functionality used to pan the map, therefore if it is to be replaced functionally when selecting an item we are presented with 2 problems: 1) What if the new area (where the operative would like to place the event icon) is out of scope and the may needs to be panned? 2) If the map is densely packed with draggable icons could users make the mistake of moving an icon rather than panning?

Right click to select, click to place

Problem 1 is that we've got a contextual menu for right click, not a problem because re-place icon can be an option of that, so that's issue 1 avoided. The problem I feel here is that this isn't intuitive enough, and what if the operator forgets they have the item selected and continues to use the map normally, placing the event wherever they next click?

Right click to select (via contextual menu) and left click to place with a visual aid

This idea sort of replicates google maps' streetview dropper. You right click the icon for the event, chose "re-place event" and your cursor is then followed by the icon indicating you're ready to place with a left click. My only worry about this is that the user may not know how to 'escape' the move if it's an accident, even if it it paired with a key command to cancel.

Click and drag with visual aid

Copies google maps' streetview dropper more than option 3, with the click and drag functionality of option 1. This time we would allow the map to pan with the cursor meaning if the scope was only slightly out the operative could pan to the right place.

TLDR: What is the best way for users to do this in terms of intuitiveness and what is least likely to cause mistakes? The users will be trained to intuitiveness should come second to ease-of-use.

  • (1) What does (left-)click do? That's a common idiom for "select" in other applications, so if you want to break it down as select + relocate, left-click seems more natural than right-click. (2) The answer to this will be affected by the properties of your map, so can you tell us more about that? How dense do movable items tend to be? How often do people pan/zoom vs just working with a static map? What other mouse-based gestures do you already support? (You mentioned pan and a right-click menu; anything else?) Is everything mouse-based or do they also use the keyboard for anything? Commented Sep 12, 2012 at 15:31
  • Is clicking on the map the only mechanism for plotting points, or can users search for a specific address/coordinates etc? If the latter, do you need to allow the user to select an existing marker and input a new location in addition to supporting the dragging and dropping?
    – Matt Obee
    Commented Sep 12, 2012 at 16:43
  • Hi Monica/Matt - The left click action grabs the map to pan, but there is no static left click actions currently. In the future other ico types will require left click for further information windows. As far as density goes it's massively variable. There might be only one icon on screen at a time or there could be a cluster - these are the 2 most likely scenarios.
    – TJH
    Commented Sep 14, 2012 at 8:00
  • @MattObee to answer your question regarding non drag-and-drop options we've not currently implemented a text only way of moving a marker but we'll need to consider one for accessibility
    – TJH
    Commented Sep 14, 2012 at 8:01

1 Answer 1


Drag-n-drop is traditionally done with left-click.

However, for you, mousedown, move, mouseup is for dragging (these are the elementary events)

Usually, click is to select a place. On Google Maps, if you click on a label, an icon or a result balloon, it select its corresponding place. On Nokia Maps, if you click on an icon or a result balloon, it selects its corresponding place. (Both products are called "places".)

click is defined as mousedown, mouseup within 100 seconds, with mousemovement less than 8 pixel in any direction in between.

(I'm roughly quoting About Face 3 from Cooper here)

What about long-click-drag?

(mousedown, movement less than 8 pixels, 100 ms elapsed, mousemovement?)

long click example

I wouldn't say it's too much intuitive - at least, it's not too much visible, but you're dealing with expert users: they do learn such things on their first workday,and won't forget it that easily I hope.

  • Thanks for your answer Aadaam. I'd considered a click-and-hold time based option but this does seem better. +1 for the very informative example
    – TJH
    Commented Sep 14, 2012 at 8:02

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