Questions tagged [spatial]

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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34 views

Correcting linear regression for change in air temperature over time

Say I collect temperature data over 5 square kilometers over the course of an hour in the evening but I want to analyze the data as though they were collected all at the same time. Naturally the area ...
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11 views

Machine learning (or Deep learning) for 2d array

I'm trying to build a map by using machine learning (or Deep learning). I have many training data like that ...
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8 views

How to include parameters from a variogram to account for spatial autocorrelation with a GLMM?

One of my supervisors told me to try to estimate the parameters from a variogram and use them as random effects in a GLMM to account for spatial autocorrelation, and I did not really get the point of ...
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14 views

On the spatial autocorrelation test on the logistic regression residuals

I'm using logistic regression of presnece-absence model with two features. To test the spatial autocorrelation I used Moran's I test. I performed the test on the residual of the model through : ...
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53 views

How to include the effect of the spatial autocorrelation in random forest algorithm?

I have spatial autocorrelation (SAC) in my observations and I want to use two species distribution models Random forests and logistic regression, I’m planning to include the SAC as an autocovariate «  ...
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6 views

Dealing with spatially correlated errors when fitting nonlinear regression models

For spatial error models (SEMs), OLS regression is still said to be unbiased but just not efficient, and therefore the variance estimates are said to be untrustworthy SEMs. Thus generalized least ...
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25 views

plm/splm in R - fixed effects panel models with time invariant variables

I amestimating the following model for crime rate: tot_crime <- log_rt_crime ~ ndvi + log_disad_inde + log_density where ndvi ...
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Ergodic spatially correlated random field

I would generate a realization of an ergodic random field. With one realization I want to be able to capture the real spatial covariance. The method I used to generate random fields with prescribed ...
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30 views

Generating spatially correlated data with assigned spatial covariance

I should generate data in the form $Z=Z(x,y)$ or $Z=Z(x)$ where $x,y$ are spatial variable, so that the spatial covariance results to be equal to an assigned function of the distance $h$ between two ...
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2answers
24 views

glmmTMB: random intercepts vs. spatial random field

I'm working on a modified example from a glmmTMB vignette (found here) using spatial covariance structures. I'm trying to show the difference between "standard&...
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24 views

How to deal with spatial autocorrelation at a global scale?

I am working a dataset that shows the size of amphibians across the world. Both a Morans I test and a Mantel's test on the distance matrices between body size and location indicate that there is ...
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Does ordinary kriging assumes a random field with zero drift?

The question is actually the above one. I'm a beginner in spatial stats and just trying to fit many puzzle pieces together. So I just wondered if ordinary kriging, in contrast to universal kriging, ...
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Extracting the fitted expected number of points from mppm in spatstat (in R)

When fitting a Poisson process model on multiple point patters using the spatstat R package (mppm function), is there a computationally efficient way to extract the fitted expected number of points ...
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Can random effects be used in the spatial LGCP package (from JSS paper by Taylor et al. 2015)?

I am reading the excellent statistical software paper found here in this link. The paper is an R implementation of Log-Gaussian Cox processes for spatial point process applications. Whilst the ...
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No convergence when fitting theoretical semivariogram to empirical?

I'm kind of new to working with semivariograms. But I just wanted to fit a semivariogramm to my data and when fitting the theoretical variogram to my empirical it tells me that: ...
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37 views

Is a spatial effect a random or fixed effect?

Below is the definition taken from Wikipedia(with some minor alterations) Consider the linear unobserved effects model for $N$ observations and $T$ time periods: :$y_{it} = X_{it}\mathbf{\beta}+\...
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8 views

Interpreting a Distance & Time 3D Variogram for Variogram modeling

I am trying to understand some concepts of variograms. I have made several variogram models in R and am trying to understand exactly what they mean. My data is ...
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29 views

Variogram fit in R not converging

I have taken a shapefile from Open NYC Data and performed the following method. My end goal is to predict Taxi trip_duration at various points across the city of ...
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26 views

How to account for spatial auto-correlation when testing for differences in community composition

I am looking to test whether several continuous environmental environmental might influence bacterial community composition in soil samples. A total of 50 soil samples were collected, but in a blocked ...
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29 views

Spatial / geographical modeling [closed]

Normally when I try to model spatial risk, I include it in my mgcv::gam model using a two-dimensional spline. Do you guys know of any other statistical methods that could be interesting for me to take ...
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72 views

Accounting for Spatial Autocorrelation in a GAM: including coordinates of points as smooth terms is not working

I have been trying to use GAM/GAMMs to account for spatial autocorrelation in residuals of a GLMM. I have explained my data in detail in this Stack Exchange question. The question also demonsrates how ...
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19 views

Variogram of categorial data?

I have a thematic map as raster data with classes assigned as numbers: 1,2,3,4. These are categorial classes and have no linear meaning. I am interested if there is spatial autocorrelation in this ...
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10 views

Spatial lag regression model with significant LM test value: Can we make deductions based on the estimates?

I have a spatial dataset with which I created a "spatial lag regression model". The "Likelihood Ratio test" (LR test) results were significant which means the addition of the lag ...
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33 views

Comparing the overall mean of Monte Carlo simulation runs involving multiple observations

I have a set of n spatial points distributed across the landscape. I have hypothesised that the location of these points is determined by a property of the ...
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8 views

spatstat::plot.envelope observed line longer than significance band [duplicate]

Using the R package spatstat I'm plotting pooled pointwise envelopes of the function Jfox calculated for different point pattern in an hyperframe. The workflow is ...
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142 views

How should I deal with spatial autocorrelation in beta GLMM (glmmTMB)? (Bird diversity)

I am trying to compare certain a taxonomic diversity index (for bird communities) calculated for squares in a map grid system (a total of 34 squares) for two different years: 1998 and 2018. My ...
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2answers
41 views

spatstat::plot.envelope observed line longer than shading

Using the R package spatstat I'm plotting pooled pointwise envelopes of the function Jfox calculated for different point pattern in an hyperframe. The workflow is ...
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0answers
19 views

Outlier detection using 2D spatial information

I have a list of sensor measurements for air quality with geo-coordinates, and I would like to implement outlier detection. The list of sensors is relatively small (~50). The air quality can gradually ...
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1answer
180 views

Running a spatial model without having a panel dataset

I am trying to run a linear probability model with spatial lagged Xs in R. The idea is to have the crime_type_1, a binary variable, as the dependent variable, and the faction as the independent ...
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26 views

Evaluating classifier with additional data

I have a data analysis problem where I have a blackbox image processing software that detects certain defects (cracks, potholes, expected objects like manhole covers, foreign objects) on a straight ...
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7 views

Controlling for population in Getis-Ord clustering with varying population density

I'm running a Gi* cluster analysis on population data aggregated into administrative areas. I'm looking for clustering of prevalence of variable A, so I create a ratio based on ...
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43 views

Is there a valid way to spatially disaggregate a country-level time series when data at the desired spatial resolution is available for a single year?

Context 3rd year public health student formulating end-of-year project proposal. Interested in exploring the relationship between economic and health outcomes in a spatially fine panel data setting. ...
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17 views

Clustering geospatial and “ordinary” data

I have big dataset (~100k) of numerical parameters and their locations (lat, lng). What approach should I choose to cluster such data? Usual distance functions won't work in such case and calculating ...
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27 views

Are identical things spatially clustered?

I'm new to working with spatial data, but I am working with a dataset of discrete plant genotypes sampled along a 1-d transect of 30 sampling points, and I would like to quantify the extent to which ...
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39 views

Spatial regression models for counts

I'm trying to model count data with both a Poisson regression model and a Negative binomial model. These counts are referred to the spread of a disease in each spatial unit area (I have 110 obs). I ...
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18 views

Circular variable in spatial GLM / SVM modeling using R [duplicate]

I am modeling spatial data using multiple rasters with the variables shown below. ...
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17 views

spatial autocorrelation in dynamic occupancy models via colext

In biostatistics, spatial autocorrelation can almost always be an issue. In single-season models, one can apply mixed models to take into account spatial cluster of study plots. I wonder whether there ...
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1answer
102 views

Interpretability of tensor product interactions in space

Spatial data (x, y) is most often accompanied by spatial autocorrelation or locally different interactions between x & y. When I want to fit a parameter across space with generalized additive ...
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31 views

Creating a covariance matrix from a distance matrix—normalizing matrix with infinity

I'm trying to simulate spatially autocorrelated data by creating a covariance matrix from a distance matrix and using said covariance matrix as the $\Sigma$ parameter of a multivariate normal. I have ...
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15 views

consider spatial autocorrelation in spatial grid analyses using GLMM

In ecology, spatial autocorrelation is a major issue. When dealing with discrete study plots, these plots can be grouped by their spatial location in order to consider spatial autocorrelation. In a ...
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39 views

Equation for a glmmTMB model with exponential spatial covariance structure

I have read description of the Spatial covariance structure with glmmTMB on this link (https://cran.r-project.org/web/packages/glmmTMB/vignettes/covstruct.html), ...
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22 views

Standard Error or Standard Deviation for error associated with averaging raster values within a polygon?

I am trying to measure uncertainty associated with a mean value for spatial data. I have: A polygon representing a spatial district. A raster dataset that was produced via a Random Forests model, ...
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44 views

Deducing information from a scatterplot

I have two tiff files in R (one modelled and one observed). Both tiffs show the spatial maps of gross primary productivity from 2000-2010. The study area is HinduKush Himalaya (http://rds.icimod.org/...
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28 views

SECR AIC compatibility

I'm a student in ecology and I'm currently doing an internship to validate the first year of my master degree in France. I have to calculate roe deer density for the Mavrovo National Park in Macedonia ...
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10 views

Area and time adjusted counts

In 2019 I went to a site and counted 4 species of birds. The size of the site was 130 hectares and I spent a total of 54 hours counting the birds. The peak counts of the 4 bird species are presented ...
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24 views

How can I determine a gaussian field for thresholding a distribution at each location of a grid?

Suppose $X(u, v) \in R$ is a random variable at location $(u,v)$ of a grid $G \subset R^2$, and $X(u,v)$ can be expectedly decomposed into two components with a unknown threshold $t(u,v)$ with $t(u,v) ...
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14 views

Inconsistent results from partial Mantel test on (non)distance matrices

Currently I am trying to look at the correlation between three matrices of ecological data. All three are forms of distance matrices (two matrices of pairwise community dissimilarities and one matrix ...
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13 views

Selecting a Model for Large-Scale Spatial Monthly Data

I'd like to perform a regression analysis with a large spatial dataset that is likely spatially and temporally correlated. I've described the data, goal, and question in further detail below: Data: ...
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33 views

Sampling Technique: Categorical Data, Many Levels

I have a data set that has a categorical variable with almost half the number of observations as categories. Certain categories have only one observation. A minimal reproducable example in R would ...
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1answer
34 views

What is the “sensible default” for the Kest function of the spatstat package?

I'm reading the documentation on the Kest function (page 731) from the spatstat package. For the argument $r$, that is the "Vector of values for the argument $...

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