Time scale axis ticks positions - d3.js

I can't figure out why second last tick in not equally spaced In This Link? I am using d3 time scale.

Assuming you're referring to the space between the "Mon 26" tick and the unlabeled tick, it's because the last tick just represents the end of the axis, not another whole day. Since you don't have any data after the 26th, d3 didn't make the axis extend a full additional day.
This last tick is called an outer tick. If you want to get rid of it, you can set its size to 0: axis.outerTickSize(0)

Related

How to auto scale Y-values for a DateTime series within a zoomed in X boundaries?

I am writing an application for Windows 10 using Delphi 11 and Steema TeeChart pro 11 components.
I use AddXY(….) to plot a DateTime series of about 1000 values as points in Chart1 with BottomAxis set to DateTime and the Leftaxis set to float.
Thereafter I zoom in a small part of the data in Chart1 using the mouse wheel or drawing a rectangle.
Then I want to plot a new time series (AddXY(….)) of 1000 values in Chart1, keeping the zoomed in min and max values for the bottom axes, but use automatic scaling for LeftAxis. Before plotting the second series I delete the first.
The second series have the same DateTime values as the first series, but the Y values are sometimes very different compared with the first series and may not be visible in the graph.
Now the problem occurs. The Left axis will be automatic scaled based on all the data points and not on the points only falling within the zoomed X boundaries.
Does TChart have a simple method to find the min and max Y-values for the second series within the zoomed in time period. I thought of using the LeftAxis.AdjustMinMax() procedure for rescaling the left axis?
Of course I could scan through all the Y-values within the zoomed in period and calculate the min and max value. Then, how do I know the starting and ending valueindex of the data points falling within the zoomed in time period? I hoped to avoid using this method due to speed resons if number of points are > 1000.
Hopefully someone more experienced TeeChart programmer than I am can give me some suggestions of the best way to achieve this.

How can I align linear and ordinal scales in d3 graphs?

I have an ordinal scale, that I am creating a bar chart with.
I create it like this:
d3.scale.ordinal()
.rangeRoundBands(js.Tuple2(0, widthOfMySvgElem), 0.1)
.domain(labels)
The labels are in fact weeks, or months, or similiar periods, and I have data for those periods.
Now, I have something like expected values, that I want to show in this graph as well.
Furthermore, those expected values can change in time, and I want to display that too.
I want to display, that I have expectedValue1 in march, and the start of April, but then at 7th of April, the expected value changed to expectedValue2, and I want to place it where the 7th of April would be on my axis. (I want to display those expected values as the straight line, that changes height as value change.)
But I have no luck matching exact location in relation to this ordinal axis.
Do you have any ideas how can I successfully align those two scales, so they will meet at the data points of ordinal scale, but that I would be able to position other values correctly as well?

dimple.js - keeping scale after reloading new data

In d3.js I can load a dataset and filter it on 'year'. This opproach gives me the possibility to calculate my d3 scales and vertical axis based on my complete dataset's max y value.
My aim is to get the graph to be visually comparable when changing view from one year to another. - With the same maxscale value, and the same relative vertical height per unit in the columns after reloading data for another year.
Do anybody know how to accomplish this in dimple.js?
Thanks :)
In the documentation there are some examples of what you're trying to achieve..
Namely, one in which the axis min and max settings are manually set..
// Setting min and max dates requires them to be set
// as actual javascript date objects
y.overrideMin = new Date("01/01/2000 9:00 am");
y.overrideMax = new Date("01/01/2000 6:00 pm");
In this case they are Time values for a day, which make sense not to change, but the same should apply.. But, you should give us some of your code examples for more specific answers.
So from chart change to chart change, you will retain the same Min & Max as the previous year.
Reference DimpleJS Advanced Time Axis

Y axis level need to be moved little left in dc.js chart

I am drawing charts using dc.js.The following is a frequency VS Day Chart
I am using the following line to generate the titles:
..something.yAxisLabel("Frequency").xAxisLabel('Day');
But the problem is as you see when the frequency is so large the Y axis title is colliding with the frequency numbers. So is there any simple way to move the Y axis title left?
The layout of auxiliary elements such as axes and legends is not completely automatic in dc.js; use .margins() to adjust where necessary.
https://github.com/dc-js/dc.js/blob/master/web/docs/api-latest.md#marginsmargins
It would be great to figure this out automatically but it is difficult to calculate, and easy to work around, so I guess no one has gotten annoyed enough to submit a fix. :)

How can I plot data of multiple days on same plot

I have some data which is collected for 6 days during 8:00AM to 11:00AM. I need to plot all the data on same plot one over other. The way I am doing now:
hold on
plot(y1,x1,':b*','MarkerEdgeColor','k')
plot(y2,x2,':r*','MarkerEdgeColor','k')
plot(y3,x3,':y*','MarkerEdgeColor','k')
plot(y4,x4,':g*','MarkerEdgeColor','k')
plot(y5,x5,':c*','MarkerEdgeColor','k')
plot(y6,x6,':w*','MarkerEdgeColor','k')
datetick('x','HH:MM:SS')
hold off
where x1 to x6 has y axis data and y1 to y6 have
y(i) = datenum(Year(1:5), Month(1:5), Input_Vector(1:5,2), Input_Vector(1:5,3), Input_Vector(1:5,4), Input_Vector(1:5,5));
When I plot using above, I get the image attached
But what I need to find patterns by observing them. So I need to have something one above other with x axis 8:00:00 to 11:00:00
I need something like and I got this by making DAY parameter constant date.
If you want to plot one day over another, then the method you used to make the second graph - discarding/replacing the date part of your datetime - is likely the best way to do it. It matches up nicely with the conceptual question that the graph answers, i.e.: "Is there a link between time of day and duration of journey, regardless of the day it was taken on?"
If you still want to preserve the day information, you could always perform the multiple plots with different line specs, and have the legend show which line corresponds to which day.
If the above question - finding a link between time and journey duration - is what you are trying to do, rather than plotting that specific type of graph, I would also try something like this:
Split your day into half hour or quarter hour slots and take the average of all data points in each block. This gives you a single value for each half/quarter hour span.
Plot this as a bar chart with error bars showing standard error (this can be done using bar and errorbars)
If I see anything, try fitting it with an appropriate model and check for goodness of fit. In your case this would probably be a Gaussian model, as your data kinda looks like it peaks around 9:20.

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