The interpolation tag has no wiki summary.
2
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1answer
40 views
Interpolation of influenza data that conserves weekly mean
For each week, I have the following count data (one value per week):
Number of doctors' consultations
Number of cases of influenza
My goal is to obtain daily data by interpolation (I thought of ...
0
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0answers
26 views
Performing linear regression analysis on two data series with different sample spacing
I have a record of one climate variable with a data point every year, and another one which has sample spacing that varies between 1.3 and 75.2 years. I even have a few ages in that series for which I ...
0
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2answers
56 views
2d interpolation method for coarsely sampled image
I'm looking for a general method for 2d interpolation of a coarsely sampled image. I'll use an example, taken from the scipy.interpolate (Python) page.
Say, I have this image, but instead of ...
0
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1answer
47 views
Backfilling ARIMA data with exogenous variable
I have time series data for a set of cities that goes back for about 10 years. I also have the data at the state level for almost 30 years. There was an event that occurred about 20 years ago, that is ...
0
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0answers
40 views
Should we always do interpolation polynomially or fill the gaps with the average value?
I have a series which takes values as 1,2 and 3. It also has some NAs. Following is a sample from the series.
series1 <- c(1, 1, 2, 1, 1, 1, 1, 2, 2, 2, NA, ...
1
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0answers
39 views
Confusion related to kriging
I was going through the wiki article related to kriging http://en.wikipedia.org/wiki/Kriging. However, I couldn't follow some derivations.
In the first figure for simple kriging, how come the ...
3
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2answers
208 views
Kriging on log transformed rainfall data
I am beginner in R. I had found in the literature that prior to performing kriging on the data, the distribution has to be investigated to check if it is Gaussian.
So, in order to check if the data ...
5
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1answer
104 views
Spatial interpolation models: deterministic vs statistical
I am applying diferent methods to interpolate continuous spatial surfaces (kriging, splines, glm,etc). Most of the studies that have enough detail for me to follow usually focus on one specific ...
3
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1answer
378 views
Non-algebric curve-fitting along weighted pointcloud (if possible using python)
I have a list of weighted 2D points taken from symmetry analysis of a human back surface. I am supposed to find the "midline" representing the most likely path describing vertebrae location (actually, ...
1
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0answers
126 views
Sparse matrix representation of a spline interpolation
I use spline interpolation within a statistical model, and the transpose of the operator turns up in the gradient of the log-likelihood. Let me set up some notation first.
If $x_1 \ldots x_n$ are a ...
4
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0answers
77 views
Spatial interpolation of vectors in vector fields
Statistical modeling is new to me and I would appreciate some thoughts on my project. I am trying to model the spatial (and possibly temporal as well) relationships within vectors in vector fields. ...
3
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1answer
133 views
How to display concentration data in space?
I have a data frame of chemical concentrations that are measurements taken from 12 locations all in the same vicinity. I have manually assigned x and y coordinates to each location (on a 0 to 20 ...
1
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1answer
53 views
Sampling an interpolated model with MCMC
Is it safe to run a MCMC by interpolating in tabulated data of a model? For background, I have output of a model that involves a set of coupled non-linear differential equations. Calculating models ...
2
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1answer
104 views
Density estimation with scaled sinc-like kernels
Given data points $x_i$ in $\mathbb{R}^d$ with function values $f_i$,
one can estimate the function at a given $x$ by
$\ \ \ \ \text{f}_{est}( x ) = \frac {\sum { w_i f_i }} {\sum { w_i }}$
with $w_i ...
2
votes
1answer
109 views
Interpolation of missing values using results produced by arima
I would like to know if anyone knows how to apply the arima results to calculate missing values in the observation period. I am looking for something similar to ...
1
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0answers
89 views
Correlate bivariate Brownian bridges
Given two independently constructed Brownian bridges (from their marginal means and variances), is there a way to correlate the sample paths?
0
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3answers
427 views
How is interpolation related to the concept of regression?
Explain briefly What is meant by interpolation.How is it related to the concept of regression?
interpolation is art of reading between the lines of a table and in elementary mathematics the term ...
1
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0answers
76 views
Derivation of equations in kriging
I have some confusion regarding some derivations in the equation of kriging of wiki article http://en.wikipedia.org/wiki/Kriging.
It says that
kriging error is given by
$$
...
6
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1answer
162 views
Using ARMA when data is missing
I am using ARMA over a dataset with missing samples. How do I treat them? Would you suggest to make linear/nonlinear interpolation or just keep them out and consider two samples with missing data in ...
5
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2answers
200 views
Confusion regarding kriging
I was reading this wikipedia article related to kriging . I didn't understand the part when it says that
Kriging computes the best linear unbiased estimator, $\hat Z (x_0)$, of $Z(x_0)$ such that ...
3
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2answers
131 views
Coefficient estimated with a binary predictor $\in \{0,1\}$, but making predictions with values between $0$ and $1$ - is this OK?
Let's say I have a variable $x_d$ that, in the estimation data, is a simple indicator ($x_d \in \left\{0,1\right\}$). I estimate a coefficient for it, $\beta_d$, along with several other coefficients ...
1
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1answer
182 views
Ordinary kriging stationary case
I am trying to understand ordinary kriging.
Say I have 3 elevation measurements: Z1, Z2, and Z3 taken at X positions: X1, X2 and X3.
I am also assuming some semivariogram: g(h) and that the process ...
3
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1answer
154 views
Interpolation in multivariate time series
I have a problem in multivariate time series. The data consist of three time series related to foreign trade. Although my client is still doing research and attempting to find monthly data for all ...
1
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2answers
170 views
Adjusting data for missing observations
I have an unbalanced panel data set of 40 cities and 20 years. It is unbalanced because the data are not collected for certain cities for every year. The data are then balanced after these 20 years.
...
0
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0answers
216 views
Similarities between different size matrices, rescaling problem
Given a series of matrices {$M_i$($m_i\times n_i$),i=1...k,$m_j,n_j \in$random} if we rescale (resize) all matrices into a ...
0
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1answer
239 views
Correlated brownian interpolation
I would like to generate conditional correlated random variables. I have a correlation matrix between normal variables, and these variables are modeled through SDEs.
What are the algorithms to ...
2
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0answers
43 views
Consistent ranked list for ROC interpolation
For classifiers with binary outputs, their performance is summarized by a true positive rate and false positive rate. To interpolate the performance between two classifiers $A$ and $B$ with their ...
1
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0answers
88 views
Co-efficient of correlation weighted method for spatial interpolation
Teegavarapu and Chandramouli (2005) has mentioned Coefficient of correlation method for spatial interpolation of moisture data that calculates the coefficients between a point and its neighbors and ...
0
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1answer
75 views
Interpolating between models in ROC space
Suppose I have two models $A$ an $B$ that predict class labels. If these give binary predictions, these will appear as pairs of (false positive rate, true positive rate) in the ROC space. We should be ...
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0answers
78 views
How to determine the number of nearby samples for spatial estimation?
In many applications e.g, in mining engineering when we need to generate a map of dispersion of an element (e.g., copper) over the field of study, to depict depletion and concentration regions we have ...
7
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1answer
331 views
What is the statistical justification of interpolation?
Suppose that we have two points (the following figure: black circles) and we want to find a value for a third point between them (cross). Indeed we are going to estimate it based on our experimental ...
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0answers
29 views
Accessing errors of 3D surface generation algorithm [duplicate]
Possible Duplicate:
Assessing error of a spatial interpolation algorithm
This is a similar question to this and this one.
I have a set of 3D points that are sampled from a terrain. The ...
5
votes
2answers
205 views
Assessing error of a spatial interpolation algorithm
I have a set of 3D points. The points have three components $x$, $y$, $z$. You can think of these points as the surveyor points that one collects from measuring a terrain for GIS purposes.
I have a ...
2
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2answers
808 views
Bicubic/bilinear interpolation in R
I have a data set of x,y,z data and I'd like to do a bicubic interpolation. x and y are spatial coordinates and z is a temperature.
Below there are two images. The ...
5
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1answer
452 views
How to simplify a stretched exponential fit?
I have data from a Monte Carlo experiment that I was hoping to fit to a model of the form
$$\log(x y) \approx \beta_0 + \beta_1 \log(z),$$
where I have many observations of triplets, $x, y, z$. This ...
5
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3answers
1k views
Fitting multivariate, natural cubic spline
note: with no correct answers after a month, I have reposted to SO
Background
I have a model, $f$, where $Y=f(\textbf{X})$
$\textbf{X}$ is an $n \times m$ matrix of samples from $m$ parameters and ...
2
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1answer
74 views
How to design a study and test the effect of dosage level on cure probability?
My goal is to quantify dosage impact on cure probability for different patients. Let's suppose I have N patients with their charateristics such as age, gender, weight.... Also let's assume there is a ...
0
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1answer
78 views
How to present a empirical study when using econometric models?
I've got a (probably easy) question in how to handle empirical studies, when there are a lot of effects involved. I have a whole bunch of variables and I'd like to analyze just a few of them. But the ...
0
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0answers
36 views
Pythonic solution for determining annual chance flooding
I would like to create a function to determine annual chance of flooding given a specific ground elevation. The data I have available to me are water surface elevations at 5 specific recurrence ...
10
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3answers
1k views
What are the advantages / disadvantages of using splines, smoothed splines, and gaussian process emulators?
I am interested in learning (and implementing) an alternative to polynomial interpolation.
However, I am having trouble finding a good description of how these methods work, how they relate, and how ...
1
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2answers
295 views
Interpolating the empirical cumulative function
The empirical cumulative distribution function of a random variable, given observations $x_\left( k \right) > x_\left( k-1 \right)$, $k \in \mathbb N$, $k \le n$, is defined as $F_{emp}(x_\left( k ...
6
votes
1answer
369 views
Averaging time series with different sampling interval
I have a few time series that were (for technical reasons) acquired with slightly different time intervals, ranging between 19 and 21 seconds.
Now, I would like to average the values of these ...
4
votes
1answer
98 views
Parametric Surface Reconstruction from Contours with Quick Rescaling
I'm looking to construct a 3-D surface of a part of the brain based on 2-D contours from cross-sectional slices from multiple angles. Once I get this shape, I want to "fit" it to another set of ...
2
votes
1answer
178 views
Multivariate Interpolation Approaches
Is there a good, modern treatment covering the various methods of multivariate interpolation, including which methodologies are typically best for particular types of problems? I'm interested in a ...
