How do you detect collision of elements in D3 v5 (Text Overlap) - javascript

I've been trying to draw a network of streets. I used paths and images to perform this as you guys can see in the image :
I am also displaying labels on top of the images with some information about them. The problem is that the data source sometimes has overlapping traffic lights in the same coordinate. And as a result of that the labels get overlapped. I was wondering what's the best way to handle those overlaps in d3 v5? I've found some similar questions but none of them seem to work in d3 version 5.
This is one question that I looked at : D3js: Automatic labels placement to avoid overlaps? (force repulsion)
I guess I am looking for something similar, but something that would work with version 5?

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D3 map SVG performance

I've been struggling the past few days to optimize performance on a D3 map, especially on mobile. I am using SVG transforms for zooming and panning but made the following observation: the overkill comes from path strokes used to fake spacing between countries.
I have uploaded a pair of sample maps for comparison:
http://www.nicksotiriadis.gr/d3/d3-map-1.html
http://www.nicksotiriadis.gr/d3/d3-map-2.html
The only difference between the two maps is the stroke path along the country paths, and the difference in performance is even noticeable on desktop devices - but more obvious on mobile. Removing the path strokes makes mobile performance a breeze..
I tried all kinds of svg stroke shape-rendering options without significant results.
Now to the question. Is there any way to remove a thin border from each country to fake the spacing between countries instead of using a stroke?
If anyone else has a different suggestion I'd love to hear it!
Update: Attaching explanation photo.
What I have drawn is this. The red arrow points to the country joints. When adding a stroke in a color same as the background to the country paths (here depicted in dark grey color) it creates the sense that the countries are seprated - however this adds a serious performance hit on mobile devices. What I am looking for is somehow re-shape the countries paths so that their borderlines are where the blue arrow points, but without having a stroke.
Update 2: People seem not to be able to understand what I am looking for, so I am updating this in order to make the question even clearer.
Let's assume that the original countries paths are shown on the left of this image. What I am looking for is a way that I can somehow 'contract' the paths inwards so that the newly created paths shown in red, leave enough empty space between them that will 'emulate' a stroke between them.
Doing this, will leave no use to having an extra layer of strokes, thus gain performance from only using paths instead of paths+strokes.
Update 2: Hello again, I seem to have found a half-solution to my problem. I managed to extract the topojson to shapefile, edit the shapefile the way I want (used a program named OpenJump), but the conversion takes away all the topojson properties I need - id, country name, so I can't convert back to the original topojson.
Does anyone have any suggestions?
D3 has a thing just for that: topojson.mesh() (see documentation). The idea is that since most countries share borders, there's no need to draw the shared borders twice. If you can draw each border only once, you get as much as 80% reduction in the number of strokes you have to draw. The mesh method does the javascript processing to turn a bunch of closed shapes (countries) into the multiline path of just the borders between them. You can then draw that multiline path into a single <path> object that you position on top of the fills.
The mesh looks like this.
Here's another example.
Finally found the answer. This radically improves d3 map performance!
1) I got my topojson file and extracted to shapefile using mapshaper.org. This gives 3 files: .shp, .shx, .dbf . From what I realized the .dbf file holds all the TopoJSON properties/attributes.
2) Opened the .shp shape file to OpenJUMP http://www.openjump.org/ - Which automatically imports the .dbf file as well.
3) I selected the countries layer and went to Tools > Analysis > Buffer.
4) Checked the Update geometry in source layer box so that the geometry is edited without losing the rest of the attributes/properties and added a negative Fixed Distance -0.1. This shrinked all the country geometries to the result I was looking for.
5) Saved Dataset as ESRI Shapefile
6) Reimported BOTH .shp and .dbf that were produced from OpenJUMP back to mapshaper.org - careful, BOTH files.
7) Exported as TopoJSON. Contains new shape and all original properties/attributes!
The following link has been updated with the new produced map; we have a 'bordered' look without the need of strokes.
http://v7.nicksotiriadis.gr/d3/d3-map-1.html
Compare the performance to this link that has the original shapes + stroke. Please try on mobile to see the performance difference!
http://v7.nicksotiriadis.gr/d3/d3-map-2.html
Also, here is the updated world map TopoJSON file in case someone wants some extra performance! :D
http://v7.nicksotiriadis.gr/d3/js/world-topo-bordered.json
There might be a couple of reasons of this behaviour (on my computer, everything is working fine at the same speed ):
Browser
Which browser do you use ? On Chrome, your exemples are working perfectly.
TopoJson
eg. previous answer.
Animation
You are launching the animation when the page is loading. You might want to add a delay (animation().delay(in ms)). There is also a function in D3: queue(), https://github.com/mbostock/queue which load the data before launching a function.
--
If none of this change your problem, and if you want it to work fine on mobile, you can try to mix D3 and Leaflet (map for mobiles), which is great in term of performance by loading tiles.
One example:
http://bl.ocks.org/zross/6a31f4ef9e778d94c204
Hope it helps

different symbols in a google charts scatter plot

I'm using the google charts library to make some interactive scatter plots. And I cannot find is whether you can have symbols other than circles as "markers" ? As far as I can see it was possible with the previous obsolete version of google charts. But is it impossible with the current one ?
Scatter chart "playground":
https://code.google.com/apis/ajax/playground/?type=visualization#scatter_chart
Currently (as of July, 2013) there is no way to do this within the chart options. You have a choice between circles and no markers, and that's it.
You could go through the code and change the SVG using javascript, changing the circles to rectangles, and manipulating the coordinates appropriately (or drawing paths, or whatever you'd like). That's really the only way to do it.
Edited to add:
Additionally, you could set a fill for the circles themselves using javascript, and make the fill any shape you'd like.
You can do it with the help of image charts. You can change the color and shape of the markers using this.Refer this link. An example for the different shape markers
Click here to see this. For more google charts related queries take a look at this jqfaq.com

Violin chart in D3

Any ideas on where to even begin with making a violin chart using d3? Does it exist already?
I've looked around and have figured out how to do it using ggplot2 and was hoping there'd be a ready-made example that I could learn from but haven't found one yet.
I suppose I could do a really painful process of making various size bars on top of each other, or taking a distribution, rotating it and mirroring it. But surely there's a better way.
I needed that for myself so here it is: violin plot
As far as I know, nobody has done this before, but it shouldn't be too hard. I would start as if I was making a line chart (or boxed instead of lines) for one half of a violin. That is, create the appropriate x and y scales and add the data in. The result of this I would rotate and translate to the correct position. Then do the same thing again and mirror it as well to get the other half of the violin.
This may sound complex, but SVG has built-in support for these operations (rotating and mirroring). You should be able to approach this pretty much like drawing a line graph of the distribution with 2-3 simple operations on top of that. Wrap everything in a function and you've got something you can call to create a violin.
It of course also depends in what form you have the data to make the plot. A line plot might not be feasible because of too few data points, but then you can easily use bars instead.

OpenLayers as a large (changing and growing) image viewer

Basically, what I'm trying to do is use a map viewer as an image viewer with the same sort of efficient tile-loading, zoom/pan awesomeness without having to build it myself.
Specifically, I need an image viewer that will allow the image to grow and change while not altering the coordinates of any older (unchanged) tiles. This means that the center point (0,0), where the image started growing from, must always remain (0,0). So I'm looking for a library that will allow me to use a very basic Cartesian coordinate system (no map projection!), which will ask for tiles infinitely in all directions with no repetition (as opposed to how map libraries just ignore y-axis above and below the map, but the x axis repeats).
There's another catch. I need zoom level 0 to be zoomed in all the way. Since the image is constantly growing, there's no way to tell what the max zoom level will be, and the coordinates need to be based on the base image layer tiles so that every tile in zoom level z contains 2^z base layer tiles.
I am wondering if this is possible with OpenLayers and how to do it. If it's not, any suggestions of other (open-source javascript) libraries that can do this would be very appreciated! I've tried playing around with Polymaps, but the documentation is lacking too much for me to be able to tell if it will work. So far no luck.
Please let me know if none of this made sense, and I'll try to include some images or better explanations. Thanks!
I ended up using Polymaps after all, since I like it more than OpenLayers, because it's faster and has much smoother scrolling and panning. I wasn't able to do exactly what I wanted, but what I did was close enough.
I ended up writing my own layer (based on the po.image() layer), which disabled infinite horizontal looping of the map. I then wrote my own version of po.url() that modified the requests going to the server for tiles so that zooming was reversed (I just arbitrarily picked a 'max' zoom of 20, then when making a request subtract the zoom level from 20) and the x and y coordinates were converted to cartesian coordinates from the standard row, column coordinates Polymaps uses, based on the zoom level and the map centered at (0,0).
If anyone is interested in the code I can post it here. Let me know!
EDIT: I've posted the code on github at https://github.com/camupod/polymaps
The relevant files are src/Backwards* and examples/backwards (though it actually doesn't work, you might be able to clean some information about how it should work).

Timeline Charts like Github.com

Has anyone seen an open-source library that produces charts similar to Github.com's commit timeline charts? Check out this profile (picked one at random) and note the bar graphs below each project.
I've been trying to dominate Flot into behaving correctly but it just doesn't have the flexibility of formatting options to come up with a decent clone. Personally, I'd prefer a Javascript implementation but I'm open to looking at server-side stuff as well.
Definitely has to be a stand-alone implementation, the application is headed to a network separated from the Internet, so Google Charts API is out of the question.
I'd suggest using jQuery Sparklines. You'll need to create two separate graphs and position them on top of one another (one for the blue bars, another for the gray bars). You'll also need to make the dotted line/legend an image, but github also uses an image for that.
Here are some decent values to get you started:
EDIT: I originally overlapped two separate sparklines with relative positioning, but it would be better to use the "composite" option to draw two graphs on the same canvas.

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