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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14 views

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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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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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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28 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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23 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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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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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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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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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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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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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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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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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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17 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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172 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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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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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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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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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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33 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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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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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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93 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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27 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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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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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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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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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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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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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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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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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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29 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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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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1answer
32 views

Uniform distribution versus a Poisson homogeneous process with Ripley's K

I'm testing astropy's RipleysKEstimator. I create a 2-dimensional uniform distribution in [0, 1), and obtain its K value for a radius $r=0.5$. It was my ...
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Clark-Evans test results contradict to L function results

I have a data set including ~300 points and I would like to see if the point pattern tends to be clustered or not. To do this, I first performed the Clark-Evans test in R: ...
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31 views

(Co)kriging / co-located kriging with heterogenous measurement errors

I have a large set of polygons on a map, some of which contain data on 2 count variables, say ($z_{1}$ and $z_{2}$) that are correlated. In fact, $z_{2}$ most likely causes $z_{1}$ without the ...
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38 views

Estimating the actual distance by using a series of measurements in between

An object is moving along a single axis, back and forth. We take $N$ snapshots of the object. For all pairs of snapshot positions $i$ and $j$, we can make signed measurements of distance $x_{i,j} = -...
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Calculating Eta squares for Spatial Models

I am trying to calculate eta squares for spatial model (spatial error, spatial lag, SAR). In simple OLS model we can iteratively calculate explained sum of squared as: $ \sum_{i = 1}^{n} (\hat y - ...
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29 views

Spatial Panel Data Analysis in R: Comparison between 'spml' and 'plm' function

So, I'm a R user and currently working on a spatial analysis on panel data. Based on my experience for these past days, I understand that spml function on ...
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Testing spatial association between two sets of points (distributed in x-y space between two concentric circles)

I have 2 sets of points that correspond to 2 biological cell types, and these cell types are distributed in x-y space in the region between 2 concentric circles (i.e. an annulus). However, the inner ...
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1answer
29 views

Measures of spatial dispersion

I have a series of data points in R^3. I am considering different measures of the spatial dispersion of these points. I have noticed something interesting. I have considered two different measures ...
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1answer
50 views

model selection for Mixed Poisson model for replicated point pattern analysis

I have fitted a mixed Poisson Point Process Model to Several Point Patterns using the mppm function from the R package spatstat. ...
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How do you interpret results from crossCorrelation in R from spatialEco package?

I want to use the crossCorrelation function from the R package https://rdrr.io/cran/spatialEco/man/crossCorrelation.html spatialEco to examine the relationship between people's perceptions and the ...
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Methods to align/reduce distance between two or more 3D graph-spaces?

I'm trying to align multiple graphs of spatial data, similar to image registration, but on a 3D graphspace of a select feature. I have a bunch of point data with x,y,z coordinates that together, ...
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63 views

Statistical method to quantify the accuracy of point clusters

I have coordinates of about 13 points from different pictures in UTM. Per point I can have 2, 3, 4 or 5 coordinates of these points from 2, 3, 4 or 5 pictures. I would like to quantify the quality of ...
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How to estimate similarity between new observations and a reference class

I have a large multivariate dataset (derived from a spatial analysis of flood events). The dataset has roughly 4000 observations (locations) each with about 500 site descriptor variables. I know that ...

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