# Tagged Questions

The field of study concerning statistical methods that use space and spatial relationships (such as distance, area, volume, length, height, orientation, centrality and/or other spatial characteristics of data) directly in their mathematical computations.

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### 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 ...
31 views

### Find the midpoint of S-curves with R

I have a bunch of curves that look like S-curves (stored in a db with Point format) and I am interested in finding this midpoint between both horizontal asymptotes for each of them. So, if X-axis ...
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### Variance Inflation Factor to Address Spatial Grouping with Binary Dependent Variable

I want to obtain reliable standard errors of the estimated coefficients from a regression of y on x. The observation for each individual consisted of a value of the y variable, which is binary, and a ...
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### How can I compare the deviation from CSR in different point patterns?

I recently discovered the many tools of point patterns analysis and this is a very interesting field. I read a lot about how to look for deviations from complete spatial randomness (CSR) and I am ...
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### Pseudo-$R^2$ in spatial regressions and Kelejian-Robinson test in R

I am currently trying to find out if there is a way to calculate a pseudo $R^2$ value from the output of maximum likelihood estimation of the spatial error model, and maximum likelihood estimation of ...
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### Spatial auto-correlation test for binary data in R [migrated]

I want to test a species' presence / absence records for spatial autocorrelation. My data contain >130,000 grids in GIS and with about 700 species' presence records. I have read that the normal ...
249 views

### statistical method for spatial correlation between images

I am working on analyzing a data set and I was wondering what would be the most statistically valid method of demonstrating that there is a strong spatial correlation between images. I have a data ...
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### How to extract “average polyline” from a set of polylines [duplicate]

EDIT: As pointed, there is already a similar question "buried" inside a larger-scope one. I'll reproduce the relevant part here: If I have multiple recordings of the same routes are there any ...
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### Reference paper and/or books about spatial data analysis, possibly bayesian

It is for my master thesis, I need to go more in depth. Any suggestion about recent works is really welcome.
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### Probability of overlap of areas in 2D space

Assuming I observe, in a unit square, $n_1$ circles of area $A_1$ (non-overlapping amongst themselves) and $n_2$ circles of area $A_2$ (again, non-overlapping) and that each of the centres is ...
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### How to measure/clarify a possible relationship between two spatial points using R

I'm quite new to the area of spatial statistics, but I'm very interest in some general principles. The last two weeks I've created an example dataset, which contains three datsets. A dataset of ill ...
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### Spatially explicit model to test effects of multiple variables

What is the appropriate model to test the effects of location, species, and size on tree growth? So I have both categorical and continuous variables I want in the model. The following graphic just ...
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### What's so Poisson about a Poisson Point Process? (or, can I generate one using random ordered pairs?)

I know there is an R spatstat function to generate a ppp (Poisson Point Process), but I'm working in python, and I am not clear what spatstat.ppp is doing behind the scenes. If I generate a an ...
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### Genetic distance over spatial scales

I have matrices of genetic distances for x number of individuals within a population and their corresponding point coordinates -one genetic distance matrix per point coordinates. I was imagining ...
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### How to interpret the selection of a variable in a model (GLM) when spatialautocorrelation is included?

This is a pretty straightforward question. I am comparing outputs of two models (binomial GLM) one including environnmental-only (ENV) variables and one including environmental and spatial variables ...
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### Does RandomForest ignore spatial independence?

I have 5 variables for each countries of the world and I need to analyze their effect and interactions on an independent variable. Random Forest would be adequate for my scope as it deals with ...
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### Given a sample of time-series spatial data, how do I determine the minimum number of spatial points that is statistically similar to the large set?

I have a solar irradience data set that was generated from 45 independent stations within a square mile. The stations are more or less regularly spaced in a grid. The data are 1Hz and are all ...
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### Strange results in kriging with geoR. Is this a bug? Am I doing something silly? Or is this data set just unfortunate?

I am performing kriging on a large number of relatively modest data sets (144 data points on a 9 x 16 grid in each data set). I was experimenting with different variogram models and other parameter ...
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### Creating semi-random planting designs in R

I want to use R to create 'random' planting plans - drawing plants manually (CAD) is neither random nor efficient - my aim is a list of plants, within an irregular region, (up to 10,000 plants) with ...
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### What is the distribution of edge lengths for a Euclidean minimal spanning tree?

Suppose that you have a Poisson point process in $\mathbb{R}^d$ with rate (density) parameter $\rho$; I particularly care about $d=2$ if there is a solution in this special case. Given a finite ...
101 views

### How to compare sampled areas to the Census?

I would like to discriminate sampled areas that are representative or not representative of their corresponding population, for a given characteristic. Suppose I have surveyed areas (i.e. Census ...
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### CAR spatial models in JAGS

WinBUGS comes with the GeoBUGS add-on, which contains a number of predefined model structures that are suitable for modelling spatial data structures e.g. geostatical structures (spatial.exp), ...
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### References for spatial modeling with Bayesian belief networks in medical applications

I want to do research in spatial data mining where I want the concept of Bayesian belief networks applied on a medical domain like, for example, cancer. I have been searching for recent papers in ...
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### 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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### 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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### determining probability of spatial pattern metric greater than some instance

Let's say I have a grid of cells from a satellite image that take on the value of 0 or 1, with 1 being forest. There are many spatial pattern metrics that measure things about this pattern such as ...
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### How to calculate spatial correlation between two variables?

I have a dataset of point coordinates of individuals and different variables of these individuals. I want to calculate if the spatial distribution of a certain variable is correlated to the spatial ...
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### Anisotropy in kriging for non gridded data

I have to perform a mapping of a DVB-T field (the TV signal), per every location I consider the median in time of the measurements, there are some issues, e.g. the variance seems to be proportional ...
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### Expected maximum given population size, mean, and variance

How would one estimate the maximum given population size, a few moments, and perhaps some additional assumption on the distribution? Something like "I'm going to do $N_sâ‰«1$ measurements out of ...
638 views

### Why is Mantel's test preferred over Moran's I?

Mantel's test is widely used in biological studies to examine the correlation between the spatial distribution of animals (position in space) with, for example, their genetic relatedness, rate of ...
543 views

### Showing spatial and temporal correlation on maps

I have data for a network of weather stations across the United States. This gives me a data frame that contains date, latitude, longitude, and some measured value. Assume that data are collected once ...
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### Comparings BIC of lme models with and without a correlation function

I have created an lme model using the same predictors both with and without a specified correlation structure based upon distance between the points (lat/long). I ...
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### How to generate normal random variable vector which is spatially auto-correlated

I would like to generate normal random variable vector $\boldsymbol{x}_1$, which is correlated with $\boldsymbol{x}_2$. Also, I would like to introduce some kind of spatial auto-correlation into ...
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### Significant difference between 2D spatial normal distributions

My problem is as follows: I drop 40 equal balls at once from a certain point, a few meters over the floor. The balls roll, and comes to a rest. Using computer vision, I calculate the center of mass in ...
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### Convergence problems created by jittered coordinates

I am creating a mixed model and including a spatial correlation. My data points include lat long values although some are duplicated. I have two questions about dealing with these. To specify the ...
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### Spatial autocorrelation (SAC) while analysing survey data

I am confused about some aspects of spatial autocorrelation usind survey data (survey which is repeated every year). I have data from 1991 to 2012 with sampling region pretty consistent every year. I ...
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### Correcting for Bias due to Larger Populations

I'm mining social networks point data to use with GIS (Geographic information system). Obviously there are going to be more posts in areas with higher population which, if uncorrected, would end up ...
455 views

### Spatial autocorrelation — GLM, autocovariate, MEM (Moran's eigenvector mapping)

I am currently working on two marine species distribution modelling and also on their overlap distribution. For this I use a binomial logistic regression model (GLM) with response being, respectively, ...
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### Generalized Moran's I test for multinomial (polychotomous) logit / probit model

Generalized Moran's I test is suggested by Kelejian and Prucha (2001). But, as far as I know, there is no empirical work using the test for multinomial discrete choice model. I am looking for a ...
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### Comparing spatial patterns to on-average-distribution by averaging intervals that overlap in space

I am analyzing spatial patterns in vegetation structure across vegetation transects. I broke transects up into 3-m intervals that move across the transect (a moving window) 1-m at a time. So, the ...
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### Propensity score matching with zip code/geographical distance

I have a test group and a control group with a bunch of covariates; one of them is ZIP code. Is there a methodology that I can use to perform a propensity score matching based on ZIP code or other ...
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### Can I use Principal Curves Analysis to fit a Vector Cloud instead of a Point Cloud?

I have recently discovered Principal Curves while trying to solve the problem I will describe below. The principle of Principal Curves is to fit a cloud point to find the "path" running along that ...
128 views

### Weighted least squares to correct for heteroscedasticity

I would like to use a weighted least squares (WLS) regression to perform tests on heteroscedastic spatial data. Each data point represents the mean of some variable over an area, and the sample sizes ...
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### Fuzzy Record Linkage of Spatial Datasets

I have two datasets describing real-estate properties Dataset 1 describes building characteristics; it includes the location of the entrance to the building along with building descriptions and ...
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### Estimating model error in $k$-nearest neighbours with strongly spatially autocorrelated training data

In the palaeoclimate world, palaeoecologists have used spatial training sets of say sea-surface temperture (SST) and related this to micro-organisms living at the locations where SST was measured. A ...
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### Using Poisson family for log+1 counts in GLM

I'm running a GLM using counts as my response variable and would normally use family=poisson. But I'm also running SAR models, which couldn't easily handle my ...
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### Effects of Re-coding a regression

I have been analysing a number of likert scale variables using spatial auto-regressive models. However, my question I think can be applied to an OLS model. After analyzing the data I obtained some ...
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### Unbiasedness condition in ordinary kriging and simple kriging

I have this confusion. In ordinary kriging we have used the unbiasedness condition which gave the sum of weights equal to one. However, in the case of simple kriging we have no such conditions why? I ...