What mean each number with slashes between them (my plot) when is used the parameter extra=101, the documenttion said "Display the number of observations that fall in the node (per class for class objects; prefixed by the number of events for poisson and exp models)", but this is not clear for me.
How I can interpret them in my plot?
What mean the first number position and always represent the same? What mean the second number position and always represent the same? What mean the last number position and always represent the same?
Thanks!
You can refer to the [vignette] link for more information:
https://cran.r-project.org/web/packages/rpart.plot/rpart.plot.pdf
extra=101 displays the number and percentage of observations
in the node. Actually, it’s a weighted percentage using the weights
passed to rpart.
Related
I am new to Google Earth Engine and have started playing with mathematically combining different bands to define new index. The problem I am having is the visualisation of the new index - I need to define the max and min parameter when adding it to the map, and I am having troubles understanding what these two end points should be. So here come my two questions:
Is it possible to get the matrix of my image in terms of pixel values? Then I could easily see from what values they range and hence could define min and max!
What values are taken in different bands? Is it from 0 to 1 and measures intensity at given wavelength, or is it something else?
Any help would be much appreciated, many thanks in advance!
Is it possible to get the matrix of my image in terms of pixel values? Then I could easily see from what values they range and hence could define min and max!
If this is what you want to do, there's a built in way to do it. Go to the layer list, click on the gear for the layer, and in the “Range” section, pick one of the “Stretch:” options from the menu, then click “Apply”. You can choose a range in standard deviations, or 100% (min and max).
You can then use the “Import” button to save these parameters as a value you can use in your script.
(All of this applies to the region of the image that's currently visible on screen — not the entire image.)
What values are taken in different bands? Is it from 0 to 1 and measures intensity at given wavelength, or is it something else?
This is entirely up to the individual dataset you are using; Earth Engine only knows about numbers stored in bands and not units of measure or spectra. There may be sufficient information in the dataset's description in the data catalog, or you may need to consult the original provider's documentation.
I have a contiguous set of numbers up to a maximum (1...y). Im trying to find in which increment (defined by another value x) a given number (z) falls within that set.
Below is an image that best describes what I'm trying to find.
Is there a formula I can use with the available information to achieve this?
n = ceil(z*x/y);
In your example, the size of the range is divisible by the number of bins, so that all bins have equal size. If that condition does not hold then there may be some further questions about edge cases.
I've been learning about flow graphs and from what I've learned, a flow graph is a directed, weighted graph that has a certain maximum flow that can be calculated. However, is there a way to randomly weight the graph with values between a certain range and gradually change the weights to maximize the max flow?
If you change the weights of the edges then it's possible that the max flow value change. I mean, the max flow value is for a graph, if you change the graph the max flow value will change too.
Ask yourself about what do you persuit whenever changing weights of edges. If you want to maximize max flow value and you have to choose weights for a certain range then by choosing the maximum value of the range as weight of all edges you will surely find the highest max flow value obtained by modification of weights in a certain range.
Is above graph maxmial but not maximum?
I went ahead and got a maximum, which is below.
Am I understanding Maximal vs. Maximum correctly?
You are right. The first graph is a maximal matching, because you can not add any more egdes to the solution. The second graph is a maximum matching, because it is (one of) the matching(s) with the highest possible sum of weights. The second graph is also a maximal matching.
Hi all this is a very simple question, but my mind is a bit empty and i can't seem to find any satisfactory results on the internet.
Given a collection of 2d points (x,y), how can I determine how tightly grouped they are together.
Thanks
I guess an example would of helped.. I am trying to measure the "wobble" when aiming at a target, so I have every point the shooter aimed and I would like to see if they were steady or if they moved allot.
It depends on your definition of "tight grouping". One possibility is the sample variance, or the corresponding standard deviation. Crudely speaking, this gives you an "average" distance away from the centre point (which can be defined either as a known point, or as simply the average of your dataset).
For a group of 2D points, this can be defined as:
stddev = sqrt(var) = sqrt(1/N * SUM { (x - x0)^2 + (y - y0)^2 })
where (x0,y0) is the sample mean (i.e. the average of all your points).
This metric will be less sensitive to outliers than e.g. the bounding box metric.
One simple way to do this is to calculate the bounding box that contains all of the points and calculate the area from that, then divide the area value by the number of points to give you a points per area value. This could be enough depending on what you need it for but could be rather inacurate.