Given a set of bivariate data (x, y), to impute a value of y corresponding to some value of x at which there is no measurement of y is called interpolation, if the value of x is within the range of the measured values of x.

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Is smooth.spline appropriate for presenting the trend of chemical concentration in a catchment

In my case,the Electrical Conductivity (EC) values are measured daily in some pints of catchment from 2007 to 2014, and around 20% data are missed, due to without probe or flux. To presenting the ...
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17 views

Imputing missing values of predictor for use in Regression Models

I have a panel data set that extends from January 2013 to July 2014. The response variable is complete for the entire period, however all of the predictor variables have values only up to June 2014. ...
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2answers
58 views

How to interpolate a variable with frequency of 5 years to annual data?

I have two time-series variables: each has 14 points with an interval of 5 years. The precise years are: ...
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40 views

What is the difference between Bézier splines and Loess curves?

I'm a bit naive on this topic, and wanted to understand the difference in the mechanics of Bézier splines and Loess curves as curve-fitting methods.
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1answer
82 views

In inverse theory, how do I transform the averaging kernel matrix to a new grid?

Rodgers and Connor (2003) describe how measurements by remote sounders can be properly compared, taking into account differences in averaging kernels and error covariances. They make the assumption ...
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2answers
82 views

Interpolating time series

what are best ways to interpolate time series? I have three data points(1980, 1990 and 2001) and I need to interpolate them. Using R na.approx doesn't seem to be what I need since the data I need to ...
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23 views

Predicting the missing data out of three values in each of the two vectors [duplicate]

I have 2 vectors of rural and urban populations of the same country. (years from 1975 to 2020) with only three values (1980, 1990 and 2001 years) in each. And I need to predict the missing data. My ...
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1answer
111 views

How to interpolate (spline, LOESS, etc.) with a mix of critical and non-critical points

The data we are interpolating is monotonically increasing (for example, a car's odometer reading). We have two types of points we'd like the solution to interpolate through. The solution surface must ...
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1answer
131 views

What is the difference between (universal) kriging and spatial autoregressive models?

As part of a course on missing observations in social/survey statistics I am trying to explore existing methods of predicting either point pattern or polygon data. I got quite confused by all the ...
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22 views

Multivariate Interpolation

I'm trying to solve a problem where I have a large set of data points. Each data "point" has 8 independent variables (input) and 1 dependent variable (the output). I got this data through ...
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1answer
36 views

Multivariate interpolation: Getting Started

I have a large set of data points received by experimentation and each point has n ,or let's say 8 in this case, independent variables and one output/dependent variable. (x1, x2, x3, ...., xn) = y ...
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90 views

SUTSE DLM on daily mean water & air temperature TS

I have two time series: (1) daily mean water temperature from 1988 to 2014 and (2) daily mean air temperature from 1968 to 2010. The water temperature time series has missing data, occurring on ...
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115 views

Interpolating time series wind data using correlation

Is there a way to use correlation to interpolate missing data? I know the wind speed in 6 locations every hour. This shows the correlation between the separate locations. Hourly Data I know the wind ...
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1answer
44 views

How can I estimate the tail of a distribution with a truncated distribution?

The broadband speed data I'm working with have all values over 30Mbps placed into a >30 category. The distribution is thus truncated. This leads to the final column in the histogram below being a ...
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0answers
39 views

How to enforce periodic boundary conditions when performing regression with sci-kit learn?

I have signals that resemble sine waves (or, more accurately, sums of sines). The data are normalized in the time domain so that there is only one cycle and all of the points lie between 0 and 1. An ...
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1answer
78 views

Denormalizing Data

I am applying Polynomial Regression to my data, however the parameters theta were always =0, i noticed that my y data or output is too large in the order of 100000 so i normalized y, i got very good ...
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1answer
174 views

How to interpolate independent variable over five-year period?

I have panel data on income and population for the years 1990, 1995, 2000 and 2005. I would like to interpolate these two variables (both independent variables), so that I have data for every year ...
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13 views

Observed versus Synthetic data

I am looking for studies that compare different spatial interpolation methods for observed data. However I am looking for studies that have also compared observed with generated synthetic data. For ...
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39 views

Interpolation of time series data

I am working on using cubic spline interpolation in time series data. I used Galdolfo and Prachowney algorithms. Now how do I obtain estimates of models of cubic spline?
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60 views

Minimum points required for fitting curve

If I need to build yield curve, n what is the minimum number of data points necessary for any interpolation method, e.g. say cubic spline or Nelson–Siegel, etc. I ma not sure if I can raise this ...
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1answer
44 views

How to take into consideration gaps in time series?

I've been analysing what is the probability of that measurement going up or down during a week (e.g. 4 times out of 7, I have 60% chances of my measurement going up) everyday for the last 100 days, ...
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29 views

Limitations of using interpolated data

I have a data set that is composed of point locations in a landscape, lets call this dataset X. Some of the points in data set X need to be grouped together because they "function" together as a ...
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1answer
248 views

Find out if there is a way to create BMI weight category variable

I am working on a project and have to find a way to break my data into percentiles. The variables that I already have are gender, age in months and BMI. If I am able to calculate the percentile that ...
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76 views

How to select a radial basis function?

Currently I am investigating interpolation of 3D data with radial basis functions (RBF) and I am wondering that there are quite a few families of such (see table1 here). However, I cannot find any ...
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1answer
132 views

Explanation of cubic spline interpolation

Can someone explain to me what a cubic spline is, and how we could use it to interpolate a function? I have searched on the internet but I would like a simple explanation.
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1answer
153 views

Kriging without covariance?

I am trying to krige monthly snowfall totals using data from weather stations and elevation. When I use a linear variogram model (set using a GUI and appears to be a good fit), the resulting layer ...
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55 views

Interpolation problem [closed]

We have the following solar meteorology parameters through satellite data with resolution of 100 km$^2$ (10 km x 10 km). Insolation on horizontal surface Diffuse radiation on horizontal ...
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1answer
84 views

How to algorithmically determine the best order of fit?

I am doing a least squares polynomial interpolation for 10,000 data sets that look mostly like one period of a sine curve, but whose values are not evenly spaced in the time domain, and can sometimes ...
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42 views

Dimension independent regression/interpolation methods?

Hopefully this question is not too simple or too general. I am working on a problem right now in which I am given different sets of data. Each data set consists of some number of samples (sampled at ...
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70 views

Appropriate algorithms for interpolating 2D plane

I have a dataset describing a signal on a 2D plane. The data can be spaced at arbitrary increments. If it was an ordered grid, I understand bicubic interpolation would be a good choice. In the ...
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455 views

Uncertainty propagation in linear interpolation

How do I calculate the uncertainties in linearly interpolated values from a given tabulated function? I am just coming back into the fold after a bit of a hiatus, and am having trouble ...
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1answer
52 views

Interpolation of spectra: uneven sampling to even sampling

I have a spectrum. Specifically, my data is relative intensity $[I_{\tilde{\nu}}]$ versus wavenumbers $[\tilde{\nu}]$. The wavenumbers are equally sampled so that ${d\tilde{\nu}} = c$, where $c$ is ...
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1answer
3k views

How do I find values not given in (/interpolate in) statistical tables?

Often people use programs to obtain p-values, but sometimes - for whatever reason - it may be necessary to obtain a critical value from a set of tables. Given a statistical table with a limited ...
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1answer
489 views

Fourier/trigonometric interpolation

Background In a paper from Epstein (1991): On obtaining daily climatological values from monthly means, the formulation and an algorithm for calculating Fourier interpolation for periodical and ...
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1answer
151 views

Stationarity - assumptions and examination

I am examining rodent captures on six permanent rodent trapping grids measuring 150 x 150 meters and consisting of 121 trap stations evenly spaced 15 meters apart. There are six such trapping grids ...
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369 views

Interpolation of influenza data that conserves weekly mean

Edit I have found a paper describing exactly the procedure I need. The only difference is that the paper interpolates monthly mean data to daily, while preserving the monthly means. I have trouble to ...
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71 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 ...
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2answers
185 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 ...
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1answer
133 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 ...
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109 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 ...
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57 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 ...
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2answers
745 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
171 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 ...
4
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1answer
960 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, ...
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0answers
229 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
142 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
275 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 ...
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1answer
70 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
169 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
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1answer
350 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 ...