Here is a Heatmap with one source (weight=0.3) :
And here is a Heatmap with multiple sources (weight=0.3) :
I use Heatmap to represent pollution level. And when I have 4 sources with weight of 0.3 (image2) I expect the same green color as on the image1.
But because Heatmaps are used mostly to represent density, they add these sources weights.
How can I prevent this from happening?
Note: I am using Google Maps Api
I think you want to use maxIntensity. From the documentation:
maxIntensity: The maximum intensity of the heatmap. By default,
heatmap colors are dynamically scaled according to the greatest
concentration of points at any particular pixel on the map. This
property allows you to specify a fixed maximum. Setting the maximum
intensity can be helpful when your dataset contains a few outliers
with an unusually high intensity.
The more points you add, the more intense the heatmap will be. Therefore, if you don't want the color to change, you can specify a low maximum intensity so it will always be green.
Related
I have to build something like a heatmap but representing the noise sources in a colour, and in the noise expansion radious keep gradient to low level. My problem is that the heapmap.js library takes sense of the points concentration.
I want that the colorize depends on the noise level, and not on the concentration of noise sources.
Also I want to use it not only over a map, also over plant plains and images.
I don't know how can I do it with heatmap.js. If anyone knows or some other libraries...
Thanks in advance!
To show heatmap based on noise level first you will have to define lower and upper bounds of your data. For example, 0 = 0dB lower bound; 10 = 200dB upper bound.
heatmapInstance.setDataMax(10);
// setting the minimum value triggers a complete rerendering of the heatmap
heatmapInstance.setDataMin(0);
Then assign weight Values to each of your data point based on the noise level.
You can assign 0 values to the sources which are quiet and 7-8 to the noisy ones. It should produce nice heatmap of the noise intensity.
Also I want to use it not only over a map, also over plant plains and
images. I don't know how can I do it with heatmap.js
AFAIK, heatmap.js uses pixel position values to plot the data, so it won't be a problem to show heatmap on anything on your screen; be it an image, map or any other canvas.
If you are talking about Google Heatmap apis, I think then it only applies for maps.
Check documentation of Heatmap.js, it is pretty straightforward.
I am working on a project where data points are visualized in the scatterplot using d3. Since it is a web application, the region is limited and a lot of points overlap. In total there are 20k points and I allow users zooming in with a brush (and its extent) on regions, but even when zoomed in there is still a huge overlap of points. An example of such a situation:
What are good approaches to still visualize underlying points, to enhance the view or perception of the points? I was thinking about maybe using transparency, but I do not know if that would do it.
It might be worthy to note that all points represent genes, so clustering them may not be very logical in terms of representation.
I would suggest trying d3's fisheye plug-in. It allows you to zoom and distort the scale with the mouse letting you zoom in on areas.
You can see an example of it used with a scatter/bubble chart lower on the page here: http://bost.ocks.org/mike/fisheye/
In addition, if you have overlap I would increase opacity, so you can see which points have lots of overlap vs. points that don't.
Here's an example graph with very clustered points that I created using both fisheye and opacity: http://crclayton.com/projects/fisheye/
It also allows you to hover over individual points to see a tooltip containing more details about them.
If the number of data points is of interest, then you could cluster the points (either on client/server side). You typically see this pattern if maps have too many markers (example cluster map).
Edit:
I am still not quite sure if I'm heading in the right direction. To visualize the quantity of points you could use a 3D visualization. Here is an idea taken from the Software Cities project:
You could basically render the position of the points on the plane and create vertical cylinders - the more points on the same spot, the higher the cylinder.
I want to create a heat map using Google API (Javascript). The problem is that Heatmaps use colors to represent the density of points. But, in my case the density of points is irrelevant. I want to create a map using a specific set of values. The colors on the map will be determined by that value only for that location. My set of values is Latency (ms).
Example: If a value is low it will appear on the map with green color. If a value is high it will appear with red color.
I´ve searched the API documentation, but the only thing i found was using "weighted locations". This is not a suitable solution, because the density of points is still considered.
I'm using Google Chart API to display a multi-line chart in my application. The graph shows daily income in several currencies.
As you can see, there is a problem when the exchange rate between the currencies is significant (20 CZK = 1 USD). You may notice the little bump at about 1 third. That's actually 18 USD which is (when the exchange rate is taken into account) about 360 CZK.
I need to scale the lines to have their maximums at the same height.
I know I could just use a multiplication mapper but then there would be wrong values in tooltips shown on hover.
What solution would you recommend? I really don't like the idea of rendering the graph on my own. Thanks.
So, what you basicly need is three different Y axes.
I would do it by rendering three graphs side by side,
or three transparent graphs absolutely positioned in one space, if it were possible to render the axes nicely.
or using different units for higher exchange rates (maybe hundreds CZK)
I have locations that have quality 'X', where X can be a negative or positive value. I would like to plot negative values of X as red, and positive values as green. Intermediate values will be yellow. The opacity of the color will correspond to local density of data.
Issue 85 proves that fusion tables alone can't do this yet. Is there a viable extension that can handle this style of heatmapping?
I've made a mockup of what I want here.
I don't know if variable transparency will be an inherent problem. Would that even be possible for a Google Map overlay?
It is indeed possible, though I was only able to solve this problem with custom heatmap code. You can see the result here.
I hope to add the ability to handle both density and data values simultaneously in this API I created. Keep checking.