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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Partitioning Spatial Dependence?

So, I have a group of nations that exhibit global spatial dependence. I want to partition the nations into groups so that, at an intuitive level at least, the "sum of the spatial dependence within ...
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14 views

Determine size of quadrat by point pattern analysis

I'm working with a considerably large spatial point dataset that is irregularly spaced. As I want to average the data based on a particular quadrat size (essentially square grids) I was wondering if ...
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18 views

Goodness of fit for a spatial panel with fixed effects and both spatial lag and spatial error

On a dataset, I performed spatial panel regressions with fixed effects, and with both a spatial lag and a spatial error (both are significant), using package splm in R (Millo and Piras 2012 Journal of ...
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19 views

Should I check the z-score if the p-value of Local Moran's I is significant?

The dataset I'm using contains income data per area. The values are not normally distributed as shown in the following diagram. Global Moran's I indicates significant spatial patterns and Local ...
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11 views

Conditional Distribution of an Independent Variable for missing data

Let $X=[X_1 X_2 X_3 ... X_p] $be a matrix of p independent variables where $X_i=[x_{i1} ... x_{in}]'$ is a nx1 vector. Let W be a nxn weight matrix based upon queen contiguity (so zero's along the ...
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Ggplot gives “arguments imply differing number of rows” error in geom_point while it isn't true - how to debug? [migrated]

I have two objects of type Large SpatialPointsDataFrame named st2 and st10. They come from the same source. They both plot without problems with: plot(st2) or ...
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1answer
30 views

How to determine if there is a spatial dependence in data?

My data consists of data measured at different positions (250 measurements in a 5x5 grid). It has been proposed that results may be somewhat dependent on the position. Looking at the data I don't ...
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34 views

PCA on spatial precipitation data time series

I have precipitation time series data stored in a 3D matrix called 'pre' (dim1/2=position (index), dim3=time). I want to do a principal component analysis in order to detect the main variance and thus ...
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22 views

Residuals plot from ripley K function on spatstat

I am a rookie on R and on spatstat package. I would like some help with the Kres function on spatstat. As is always wise to plot the residuals from any kind of ...
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1answer
40 views

Bayesian models vs Bayesian network models

I'm new to statistical modeling and working on applications in spatial property prediction. Can you help me understand the difference between a hierarchical bayesian model and a bayesian network ...
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0answers
37 views

How to deal with underdispersion with binomial data

I'm working with a pretty large dataset (n = 4,500) where 10% of my points (pixels in a GIS landscape) are 1s and the rest are 0s. The full model for my data looks something like this: ...
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17 views

About Hypothesis Test In Spatial Regression

I'm doing estimation of spatial lag/error model using R package "spreg"/"spdep". But I can't find any method to do hypothesis test after regression. For example, I want to test whether two ...
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33 views

Spatial analysis separating size from location in mri

Has anyone seen, done or understand how I can go about analyzing MRI datasets that have been registered to standard (MNI) space. What I´d like to do is analyze the effect on survival of lesion volume ...
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35 views

Spatial cluster analysis

Let's say I have a structure like this : This is a spatial region with measurement of plant population in each site. Black and red represent two regions with different intensities.The question is ...
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22 views

Bayesian Spatial Prediction: What is f?

I'm working my way through Gelfand, A.E. & Li Zhu, B.P.C. (2001). On the change of support problem in spatio-temporal data. Biostatistics, 2:1, 31-45. I'm stuck at: This is absolutely the ...
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1answer
125 views

Plotting a “posterior median surface”

As part of reproducing a model I described partially in this question on Stack Overflow, I want to obtain a plot of a posterior distribution. The (spatial) model describes the selling price of some ...
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0answers
60 views

Statistical methods to compare spatial maps

I would like to compare 4 radon flux maps (Bq m-2 s-1) generated using different methods. All of the maps use same projection and have same resolution. I am having trouble finding statistical ...
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0answers
29 views

Find linear subsets in a 2D point (xy) data [duplicate]

My problem is the very idea of how to start the analysis of 2D point patterns, specifically how to find linear trends within their spatial pattern. I have XY data points which are organized like in ...
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41 views

'Extrapolate' a probability density to a different support

here is my scenario: I have N triangles and N probability distributions (of independent variables), and the support of the ith probability distribution is just the ith triangle. The triangles may ...
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1answer
41 views

Principal component (PC) as a substitute for colinear covariates?

I am working on a spatial linear regression and I can tell there is collinearity between covariates. Can I use PCA (Principal Component Analysis) images instead of original covariates to estimate the ...
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1answer
23 views

online resources for spatial analysis [closed]

I am wondering about some good online resources for learning how to implement spatial statistical techniques, like Moran's I and Geary's C, or even K Nearest Neighbors...any help is appreciated. ...
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27 views

Testing if points on a line are over/under dispersed

I have a series of about 1000 points on a chromosome and I want to know if they are clumped, over-dispersed, or neither. The chromosome can be viewed as a 1-dimensional. I've looked over some ...
7
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1answer
107 views

Why do you have to provide a variogram model when you are kriging?

I am very new to spatial statistics and watching lots of tutorials, But I don't really get why you have to provide a variogram model when you krige. I am using the gstat package in R, and this is ...
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39 views

Geographically Weighted Regression in MATLAB

Does anyone know how can i perform Geographically Weighted Regression in MATLAB?i am a newbie. also, can someone provide sample in solving GWR?
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1answer
16 views

Including covariates increases spatial patterning rather than reducing it

I am fitting a series of Bayesian spatial models with an intrinsic conditional autoregressive (iCAR) structure. In these models, I begin by fitting an empty model (null) and then add successive sets ...
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1answer
32 views

Spatial partitioning of direct, indirect and total impacts

I am trying to reproduce table 2.1 (p. 41) of LeSage and Pace (2009) by means of the open R software. This is a table containing the direct, indirect and total impacts of a SAR model (since the ...
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1answer
39 views

Geographic regression

I'm working on a project to estimate real estate and started with some classique techniques, such as linear regression etc. The obtained results are already going in the good direction, but to get ...
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1answer
54 views

Spatially auto-regressive two-stage model

I'm working on a project in which I use a 'Generalized Spatial Two-Stage Least Squares' model, mostly known as $y= X \beta + \lambda W y + u$ and $u = \rho M u + \epsilon_n$ where $y$ and $u$ are ...
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11 views

Adding the variances of spatially correlated data

I have a geographical grid, for every cell in that grid I know that the variable I am looking at is normally distributed and I have its mean and variance. Now, imagine I am looking at an individual ...
2
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1answer
47 views

Disaggregation of spatial autocorrelation parameter

I have data aggregated at state level. When I estimate a spatial autoregressive model such as $$y = \rho W y + X\beta + \epsilon$$ on this data, I see that the autoregressive parameter $\rho$ is ...
0
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1answer
36 views

Classifying a set of photos to places

I want to cluster photos and map them to places. As input I have Photos with locations (lat, long) Places - some as (imprecise) bounding boxes, some just as points, maybe others as bounding ...
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40 views

Probability of vector similarity wrt dimensionality

I'm trying to show that the probability that two vectors are similar to each other increases as the number of dimensions decreases. I define similarity between two vectors $a = [a_1, a_2, ..., a_n]$ ...
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86 views

(Spatial) distance between cluster means

I'd like to cluster points based on a distance criteria. As I want to cluster spatial points I am using euclidean distance and a hierachical cluster approach. In a final step I'd like to cut the ...
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1answer
87 views

Analysis of spatial data over time and space

I have a data set having year-wise monthly average of minimum and maximum temperatures of 32 stations around the country since 1948. The latitude and longitude of the stations are given as well. I ...
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20 views

Is lm.morantest valid on residuals from geeglm fit of binary data?

Is it valid to apply lm.morantest (in the package spdep) to test for spatial autocorrelation among residuals from a Generalized Explanatory Equation (geeglm in geepack) model fit of binary data? If ...
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66 views

Significance of Spatial Data

Background: It's common in many aspects of science to want to determine if the trends shown in spatial data are significant. In my field of familiarity, climate science, authors often show the ...
5
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1answer
108 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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1answer
17 views

Similarity between two samples of spacialized data ignoring local fluctuations

I have data from a set of sensors, and would like to measure similarity between two samples of data ignoring local fluctuations. My problem is, my sensors are not regularly placed : some are quite ...
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0answers
60 views

Time series, x-y coordinates, regression, R [closed]

I have data in the form of these columns: date, x coordinate, y coordinate, value A, value B, value C, value D, etc. (I don't see the possibility to copy an ...
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0answers
27 views

Spatial and temporal effects in water quality data

The data I have is 20 sampling points in a water distribution network that have been sampled weekly during 4 months for different parameters (chlorine, turbidity, disinfection by-products, ...). Some ...
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0answers
33 views

Statistical test for spatial difference of incidents

I have an area divided into grids. I'm looking for a method to determine statistically, if the occurence of criminal incidents for two time periods is significant equal. I have two datasets with ...
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1answer
44 views

spatial-location/time-series prediction models

How efficient it is to build predictive model. However, every crime is dependent on three factors: Time, Spatial Location and people behavior. Statistically, we can't measure people behavior (we ...
3
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1answer
79 views

Is a valid correlation function on $R^2$ (a plane) also a valid correlation function on a cylinder

Suppose to have a valid correlation function on $R^2$ that depends on the distance. For example if the distance between two point is $h$, the correlation function can be $\exp(-\phi h)$, where $\phi$ ...
2
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1answer
100 views

Test for Complete Spatial Randomness taking into account background distribution

I have a set of points on a grid which is a subset of a larger background set of points on a grid. I would like to test if the subset points are randomly distributed (or not). If it helps, here is ...
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0answers
19 views

SPM for spatial analysis

Do you know of any study where researchers have used Statistical Parametric Mapping for spatial data only? I found a lot of studies that used it for time-series analysis, but does this analysis work ...
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1answer
116 views

What causes a U shaped pattern in the spatial correlogram?

I've noticed in my own work this pattern when examining a spatial correlogram at varying distances a U-shaped pattern in the correlations emerges. More specifically, strong positive correlations at ...
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0answers
86 views

How to interpret coefficients in the spatial lag and spatial durbin model?

How do I interpret the coefficient for the spatially lagged dependent variable in the spatial lag model or spatial autoregressive model (SAR) (y = αιn + ρWy + Xβ + ε) and how do I interpret the ...
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0answers
54 views

Hypothesis Testing with Spatial Data

I have production data for several wells. I know that a subset has been treated with a product, and I'd like to determine if the difference in production is due to the product treatment, or the ...
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54 views

Spatial patterns analysis for images

i have done some research about spatial patterns analysis, using some spatial statistics mesures, all the cours that i found talks about spatial statistic in the context of GIS, in the context of ...
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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 ...