topic Re: plotting dots at scatter chart in QlikView

plotting dots at scatter chart

Wed, 07 Dec 2011 11:05:03 GMT

Hi all,

In my current working file i am trying to place the value in at a particular degree location.

If i select value in a field i.e; AngleTabPos=90.0812334 , then in scatter chart in needs to plot that dot at 90degrees from centre 0.

Please the attached file.

How can i work on this ? And please can you help on this.

Thanks in advance.

plotting dots at scatter chart

jagan — Wed, 07 Dec 2011 11:57:28 GMT

Hi,

Change the order of the expressions in the char, i.e, make the second expression "RadialPos" as first expression.

Hope this helps you.

Regards,

Jagan.

Re: plotting dots at scatter chart

Wed, 07 Dec 2011 12:09:28 GMT

Hi ,

I tried it, but Its not working.

Is there any other way to work on it.

Thanks

Re: plotting dots at scatter chart

jagan — Wed, 07 Dec 2011 12:57:19 GMT

Hi Ravi,

Check the attachment.

Regards,

Jagan.

Re: plotting dots at scatter chart

Wed, 07 Dec 2011 13:15:49 GMT

HI ,

can you please explain what the below expression mean ?

If((Only ([AngleTabPos]) > 90 AND Only ([AngleTabPos]) <=180), Mod(Round(Only ([AngleTabPos])), 90),

If((Only ([AngleTabPos]) > 270 AND Only ([AngleTabPos]) <=360), Mod(Round(Only ([AngleTabPos])), 270) * -1,

If((Only ([AngleTabPos]) > 180 AND Only ([AngleTabPos]) <=270), Mod(Round(Only ([AngleTabPos])), 180) *-1, Only ([AngleTabPos]))))

Thanks

plotting dots at scatter chart

jagan — Wed, 07 Dec 2011 13:21:07 GMT

Hi,

Is this what you are expected? Is the graph is correct?

If AngleTabPos is between 90 and 180 then we need to show this in Top left and the value should be less than 90, so I taken the remainder by dividing it with 90.

Same way for 180 to 270, divinding with 180,

271 to 360 dividing with 270.

So, that always I will get a value below 90 degrees.

Regards,

Jagan.

Re: plotting dots at scatter chart

Wed, 07 Dec 2011 13:33:31 GMT

Hi Jagan,

First thanks to you sharing your knowledge with me.

i didn't get exact result what i am trying to work from your attached file.

What i need is if i click any value in AngleTabPos , that value should plot as a dot and the dot should loacte at its degree values as seen in image.

Ex1: if i click AngleTabPos= 359.9502608980, then its value dot should plot at near to 360 degree shown in image

Ex2: if i click AngleTabPos= 270.0088420703, then its value dot should plot at near to 271degree shown in image

Ex3: if i click AngleTabPos= 90.012123503, then its value dot should plot at near to 91degree shown in image.

I hope you understood what i am trying to work.

Thanks

Re: plotting dots at scatter chart

johnw — Wed, 07 Dec 2011 23:21:38 GMT

If AngleTabPos is the angle, what's the radius? Angle123Pos? Probably not, but just substitute in whatever you want as the radius, or don't do the multiplication at all if you don't care what the radius is, and are ONLY plotting an angle. Just use trigonometry:

x = Angle123Pos*cos(pi()*AngleTabPos/180)
y = Angle123Pos*sin(pi()*AngleTabPos/180)

For performance, I suggest computing these x and y values in your script. I couldn't do that in the example since I don't have your QVD. I'd probably use fixed axes based on the max radius, or possibly rangemax(max(ScriptX),max(ScriptY)), and you also need to make sure your charts are sized so that both axes have the same scale.

I may, of course, have misunderstood the question.

Re: plotting dots at scatter chart

Thu, 08 Dec 2011 07:53:21 GMT

Hi John,

Thanks for your reply,

The Radius Field is the RadialPos,

From Your Expression i just replaced the Angle123Pos with RadialPos field. And in axis of X and Y replace with RadialPos field.

Before the image is in Anti-Clockwise Angles, but now i am trying to work in Clockwise Angles. What should i change in expression for clockwise Angles.

If any doubt please reply me, i will try to give more clearly.

Please see the modified attached qvw file.

Thanks in advance.

Re: plotting dots at scatter chart

johnw — Thu, 08 Dec 2011 17:05:56 GMT

Heh, I'm responding to something you've removed from your post, but in case you're still wondering, and since I already had an example file, and since I think it's an interesting question that others may be curious about, I'll answer anyway. You'd asked, "Can we increase the dots size in diagram for only which are grouping or overlapping with other dots in 1 Pixel distance. And these Overlapped dots should have a different color from which are not overlapped dots."

Yes we can, but what is the purpose of the different color and size? If you're just trying to make denser regions stand out more, I think a better solution is to use an argb() color, so that multiple dots build up a stronger color. For instance, argb(100,0,0,0). You could also use a variable for the transparency, and have a slider or drop down selection for values. Sometimes different patterns are more obvious at different transparency values.

If you really do want to change the color and size of the points, you can do that, but if you have a lot of data points, it can get quite inefficient. Fortunately, that inefficiency can be moved to the script, but with enough data, it will eventually bog down too much to be practical. I don't know how much data you have, though. In any case, the attached example shows both script and chart versions of the idea.

You'll need a little modification to match your example. It's looking for clusters of at least five. For clusters of two, just change the 5 to 2 in the script and in the third chart expression of the chart that appears when you press the button. You'll also want a smaller cluster radius for your data (it's using 2.5, hidden as 6.25, the square of 2.5). If you want it to be a pixel, then figure out what a pixel corresponds to.

Re: plotting dots at scatter chart

johnw — Thu, 08 Dec 2011 17:10:20 GMT

ravikumar_ajzaas wrote:
Before the image is in Anti-Clockwise Angles, but now i am trying to work in Clockwise Angles. What should i change in expression for clockwise Angles.

Nothing. You don't change anything for clockwise angles. The sin() and cos() functions should work just fine on negative angles. Unless you mean that your data will have an angle of 60 degrees when what it really means is an angle of -60 degrees. But in that case, just flip the sign.

Re: plotting dots at scatter chart

Thu, 08 Dec 2011 17:21:10 GMT

Hi John,

Why i removed the post is , i thought to clarify the first task i.e; plotting the dots in clockwise,

After completion of this i thought to ask it later.

Now what i needs to change in the below expression for clockwise

x= RadialPos*cos(pi()*AngleTabPos/180)

y= RadialPos*sin(pi()*AngleTabPos/180)

Please see the attached file in previous post, so in that its having an new image how the angles should plot.

Thanks in advance.

Re: plotting dots at scatter chart

Thu, 08 Dec 2011 17:34:31 GMT

John i didn't get you clearly in your previous mail,

What i am trying to achieve is

if i click AngleTabPos= 359.9502608980, then its value dot should plot at near to 360 degree shown in new image. In the same way for all the values in AngleTabPos.

I hope you got what i am trying .

Thanks in advance.

plotting dots at scatter chart

swuehl — Thu, 08 Dec 2011 17:52:00 GMT

Just exchange the definitions for x and y?

Re: plotting dots at scatter chart

johnw — Thu, 08 Dec 2011 18:09:43 GMT

Ah, sorry. My screen is only 1028 wide, and your new image was off my screen, and I didn't even think to scroll over and look.

If you look at the chart, you may notice that you can get the real angle by subtracting this new angle from 90 degrees:

0 -> 90
90 -> 0
180 -> -90
270 -> -180

RadialPos*cos(pi()*(90-AngleTabPos)/180) as X,
RadialPos*sin(pi()*(90-AngleTabPos)/180) as Y,

But there's a better approach. You may also notice that to get the new results from the old results, you merely need to exchange X and Y:

0 -> (1,0) -> (0,1)
90 -> (0,1) -> (1,0)
180 -> (-1,0) -> (0,-1)
270 -> (0,-1) -> (-1,0)

RadialPos*cos(pi()*AngleTabPos/180) as Y,
RadialPos*sin(pi()*AngleTabPos/180) as X,

Edit: Stefan beat me to it. I blame people coming into my office and asking me QlikView questions in person. I should have hit "post" real fast before answering.

Re: plotting dots at scatter chart

Thu, 08 Dec 2011 18:20:41 GMT

Thanks John and Swuehl.

For Overlapped dots should have different color, why it is bcoz the user can have an idea while looking the image itself he knows that there are some overlapped dots in around 1 pixel distance.

And the data in current appliaction will contain large amount of data.

If had a question,

if we are having a large data whether it is better to show in Transperency way or making the dots bigger which are grouping around 1 pixel distance.

you mentioned last point in your previous post that is

It's looking for clusters of at least five. For clusters of two, just change the 5 to 2 in the script and in the third chart expression of the chart that appears when you press the button. You'll also want a smaller cluster radius for your data (it's using 2.5, hidden as 6.25, the square of 2.5). If you want it to be a pixel, then figure out what a pixel corresponds to ?

Now how can i set that overlapping dots with in 1 pixel in my application same as like what you sent application.

Thanks in advance.

plotting dots at scatter chart

johnw — Thu, 08 Dec 2011 18:42:56 GMT

If you're trying to highlight overlapped dots, I recommend just using transparency. Make single dots visible, but as light as is otherwise practical. This won't work well, though, if you expect to have a lot of dots in the same pixel, and then huge blank areas in the chart. I think I know how to handle that, though, if that's what you expect. Let me know, and I can work up an example. Basically, though, you would assign discrete pixels values for X and Y, assign pair IDs to pairs of X,Y values, plot the pair IDs, and set your Z value to the count of records.

Re: plotting dots at scatter chart

Thu, 08 Dec 2011 18:58:14 GMT

hi John,

Yes,In same pixel i may have lot of dots.

Please can you provide the example of this in which i attached recently qvw file.

Thanks in advance.

Re: plotting dots at scatter chart

johnw — Thu, 08 Dec 2011 20:27:08 GMT

It doesn't work as well as I'd hoped, as QlikView wants to control the bubble sizes itself, and all I can specify is the relative sizes. I "solved" this once in a trivial example by using a reference bubble larger than the others, displaying it in white, and putting it behind the rest. That then fixed the size for the others, and I could then give them exact sizes. I'm not seeing a clean way to apply that here yet given the realities of multiple dimensions and the ability to make selections. I also can't keep working on this - this looks like a small project instead of a quick question, and I have my own work I need to get back to.

Anyway, I carefully sized the chart so that each sub chart is 200 pixels by 200 pixels between -1 and 1. That means that each pixel is 0.01. So we just round off X and Y to 0.01. Give it a Coordinate field combining X and Y, plot coordinates, count(MK). That's the gist of it. The color expression is now hiding in the first chart expression.

Maybe it'll be useful as a starting point. But if this is your real data, I'd probably still just handle it with transparency, perhaps like the second tab. Use very light values to see the tiny clusters of multiple defects in a single pixel. Use darker values to see bigger problematic areas. You could use a drop down instead of a slider - that's what I did for one of my real applications.

Edit: Also, if you can have lots of dots in a single pixel, and it's important to see that density, you may want to use a larger chart size. This might work as an overview, but if you really want the details of these defects, I'd have a tab where almost the whole page is a single scatter chart of your defects. Make them pick a specific mold if that's important.

Re: plotting dots at scatter chart

Thu, 08 Dec 2011 20:44:22 GMT

Thank you John for sharing the knowledge with me. And this will be helpful to me.

How you provided the Red Color for grouping dots ? Where i can change the color instead of Red to Green.

Thanks