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Questions tagged [autocorrelation]

A quantitative measure of the linear relationship among values in a dataset and the values (from the same dataset) at nearby locations.

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15
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2answers
5k views

Regression Model and Spatial Autocorrelation

I have used OLS and GWR for validating the dependencies between two distinct database. The Residual Square for GWR is 0.82 and thereby making it the right regression model to be used for determining ...
14
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4answers
9k views

Implementing Spatial Autocorrelation using QGIS or PostgreSQL or any other free application?

I am a total newbie on the GIS scene so I hope this is not a stupid question. I have two layers in a PostgreSQL database. The first layer contains points where events happened in Europe. The second ...
10
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1answer
951 views

Interpreting semivariogram with high nugget effect?

I made a semivariogram in R using package gstat, variogram() function. I want to see if there is spatial autocorrelation in the residuals of my model (species abundance as a function of habitat, ...
8
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1answer
4k views

R raster Package Moran's I interpretation

I am using raster package to calculate the local Moran's I . The example gives the range of Moran's I between - 1 to 2.47. On my own data I have see the value range -3.070423 - 7.228558 How can Moran'...
7
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1answer
2k views

Help interpreting Moran's I and Geary's C results

I've got some doubts about how to interpret some results for a work. And I) would like someone could confirm or improve my conclussions. I made a correlation analysis with SEXTANTE software in gvSIG. ...
7
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1answer
1k views

Spatial outliers detection in R?

What is the best way to detect spatial outliers in R? With spatial outlier detection I mean: Discover the objects whose non-spatial attribute values are significantly different from the values of ...
6
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2answers
15k views

Interpreting Moran's I results

I have a sample of data taken from regions of a country! i want to test if there are any spatial autocorrelation on my data using Moran Indice test. the null hypothesis: is that there is no spatial ...
6
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1answer
1k views

Classical or robust variogram for incorporation into generalized linear model

I'm modeling counts of organisms over time at eleven locations. I'd like to account for temporal autocorrelation in the counts, assuming it's present. As the data are not equally spaced in time, I'...
5
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2answers
1k views

Specifying Bayesian Spatially lagged dependent (SAR) variable regression in winBUGS or Stan

I have been looking for code example on how to specify a SAR spatially lagged dependent variable regression in winBUGS (geoBUGS) or, if possible, in Stan. I mean, something of the format: Y = beta_0 ...
5
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1answer
555 views

Algorithm for spatial clustering?

I have a series of 2D maps with values ranging 0.0 to 1.0 spread all over. The algorithm that produces them is an application of the fractional Brownian motion. Each map measures 101x101 pixels or ...
4
votes
1answer
328 views

Can I ignore very low levels of spatial autocorrelation in my data?

I have >1 million postcodes clustered in ~7000 middle super output areas for England and Wales which I'm analysing using MLwiN. I have used a multilevel model with random effects and have clustered ...
4
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2answers
6k views

Variogram model fit compatability among geoR, gstat, and nlme packages in R

I'm trying to specify the covariance structure parameters in a linear mixed model (using the correlation structure facilities in nlme). The parameters are estimated from a gstat or geoR variogram ...
4
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1answer
317 views

Spatial autocorrelation analysis (Global Moran`s I) suspicious z-score

I have a doubt concerning the Spatial autocorrelation analysis Global Moran's I, in ArcGIS 10.2. I did the analysis with 3.372 features of a defined study area, and it showed that the features are ...
4
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2answers
533 views

Autocorrelated DEM with QGIS or Grass

I was wondering if there is a way to make an Autocorrelated DEM within QGIS or Grass. I am looking to do this with stereo aerial photography. I am able to do this with a number of COTS tools, but I ...
4
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0answers
59 views

Using spatial regression on interpolated surfaces? [closed]

I have two raster surfaces where I want to test to see If any relationship (A depending on B) can be found and if so if that relationship is statisticaly significant. What are key issues to consider ...
3
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0answers
787 views

Calculating spatial autocorrelation of raster values?

R is perfectly willing to compute a Moran's I statistic (and probably all of the other autocorrelation metrics) for a raster. As best I can tell, PySal and ArcMap's autocorrelation tools specifically ...
3
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0answers
410 views

Interpreting Global Moran's I and should I krig?

I am trying to weigh up if kriging (or cokriging) the residual error from my model is a valid approach. My first step was to compute whether the error is spatially autocorrelated. I have done this ...
3
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0answers
40 views

Finding closest anticorrelated polygon or automate what is learned in semivariogram?

I am trying to do spatial autocorrelation of sorts based on a layer of polygons of mean rainfall data. I want to see how rainfall deviates from a certain point on the landscape. Essentially, I want to ...
3
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0answers
775 views

Problems with spatial autocorrelation in Geographically Weighted Regression (GWR) analysis [closed]

I have conducted an Ordinary Least Squares (OLS) and Geographically Weighted Regression (GWR) analysis in ArcGIS where I have tried to predict biodiversity patterns in an area. When I examine the ...
2
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2answers
1k views

Moran's I on 2D arrays/rasters?

I would like to apply Moran's I spatial auto-correlation measure to 2D arrays or raster files in Python and I am wondering if there is an available implementation for it. I know Pysal offers an ...
2
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1answer
325 views

Compute Moran's I on more than one attribute

I am trying to compute global Moran's I to check for spatial autocorrelation among areas of a city. I am using python, in particular geopandas and pysal. My geodataframe looks like: District_name|...
2
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2answers
932 views

R - What is the purpose of .GAL lattice file?

Could someone please explain to me what the purpose of a .GAL lattice file is? I want to see if my data are spatially autocorrelated and I've been following Bivand (2013). I have loaded my polygon ...
2
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1answer
1k views

Choosing value of Moran's I to say existence of spatial correlation?

I am a GIS beginner. Usually we use Moran's I to evaluate spatial autocorrelation. Everyone knows the Moran's I coefficient ranges from -1 (uniform) to 1 (clustering); I = 0 means no correlation. If ...
2
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2answers
759 views

Geary's index of spatial autocorrelation

Does anyone knows If there is a way to calculate Geary's index of spatial autocorrelation on open source gis?
2
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1answer
223 views

Spatial correlation

I want to do spatial correlation with many variables. In fact when I do correlation densities points results are better than when I work with attributive data. Can I use the result of the density of ...
2
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1answer
557 views

What is the difference between spatial regimes and spatial heterogeneity?

Let me cite excerpts from the GeoDA-Gloassary (https://geodacenter.asu.edu/node/390) Spatial regimes: Spatial regimes are a form of spatial heterogeneity, which implies structural differences ...
2
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1answer
76 views

Conflicting results for spatial autocorrelation tests

I am working with an imbalanced (5%/95%) presence/absence dataset. I've created 25x25 m. raster cells that are categorized '1' or '0'. My Geary's C result (~0.993) and Moran's I result (~0.0045) are ...
2
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1answer
127 views

A way to measure whether two variables have similar spatial distributions?

I'm doing a project that's looking at a certain disease outbreak and vaccination in California counties using arcmap. I have aggregated data joins for disease outbreak rate, personal belief exemptions,...
2
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0answers
419 views

Removing spatial autocorrelation (SAC) using Moran's Eigenvectors and predict distribution?

I successfully managed to incorporate moran's eigenvectors as predictor to my species distribution model using GLM (logit). I followed Dormann et al. (2007) and the appendix. I think I got corrected ...
2
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0answers
71 views

Is aggregating points to areal units ever useful - Spatial statistics

I have a large point dataset of a population (By population, I mean that it was not a sample e.g. all houses in a county with an attribute such as size, price, age, etc.). Each point represents each ...
2
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0answers
38 views

Spatial Autocorrelation with a low number input feature

I am an archaeologist using ArcGIS to run spatial statistics/analyses on my data. I want to study the spatial autocorrelation of artifact categories found within house structures across an ...
2
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0answers
156 views

Determining spatial cluster of park types in ArcGIS

Question 1: I am trying to determine which (if any) of my different park types are spatially clustered across my study area (city boundary). There are 162 total parks, 9 nominal categories (which ...
2
votes
1answer
2k views

Lagrange Multiplier in lm.LMtests (spdep package for R)

Are the Lagrange values comparable in lm.LMtests? If both RLMerr and RLMlag are significant, would the test with the largest Lagrange value be considered 'better' at explaining the spatial ...
1
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2answers
250 views

Testing species distribution model residuals for spatial autocorrelation?

I build a species distribution model with data from location A and tested it on location B. The picture shows a rastermap of location B and what I guess should be the model residuals. Green - are ...
1
vote
1answer
181 views

How to work with Spatial Autocorrelation (Morans I) on equal weighted point

I have a point feature class. All points are the same, it's not weighted. I want to use Spatial Autocorrelation (Morans I) tool but it only takes a field for weight. I tried fooling it by adding a ...
1
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1answer
627 views

Accounting for spatial autocorrelation in rasters

Background: I have a set of fine resolution rasters for the Florida peninsula. These rasters are going to be used in species distribution modeling. Many of these rasters represent variables that are ...
1
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1answer
177 views

Inputs for spatial autocorrelation

I am trying to use the spatial autocorrelation function in the statistical analysis toolbox but I am unsure what I need to set as the inputs. I want to use it to test for autocorrelation in a set of '...
1
vote
1answer
68 views

Geographically Weighted Regression with overlapping polygons

Is it statistically correct (or possible at all) to calculate a spatial regression with (partly) overlapping spatial areas? I have market areas as the spatial unit with different sociodemographic, ...
1
vote
1answer
108 views

Generate spatial weight matrix from file in ArcGIS

I am trying to create a spatial weight matrix from an existing file in ArcGIS. I need to use another file, as opposed to generate the weights in Arc, because I define non-standard weights. The ...
1
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1answer
224 views

Moran's I: Selecting the best option for conceptualizing the spatial relationship between # births & county locations

I'm using Moran's I to see whether there are clusters of births rates present among the 83 Michigan counties, and, if so, whether the clustering is statistically significant. The inputs are the ...
1
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1answer
787 views

Test Statistic, p-value interpretation for Local Moran's I [closed]

I am using Local Moran's I in the spdep in R. See this question: https://stackoverflow.com/questions/44104008/spatial-autocorrelation-between-time-series-in-r?noredirect=1#comment75251231_44104008 ...
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1answer
232 views

Autoregressive parameter from autocorrelation using R

I was wondering how to get autoregressive (AR) parameter ("rho") from an autocorrelation plot using R. Below I generated a correlated data and then provided a simple approach to produce an ...
1
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1answer
399 views

Spatial correlograms for binary raster?

I have binary raster data (deforestation hotspot or not) that I would like to plot spatial correlograms for in R, to look at spatial autocorrelation over different spatial lags. I came across this ...
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0answers
30 views

Spatial autocorrelation coefficients interpretations

I have this result for SDM estimates in R with R2 of 54%. Is the lambda (= -2.04) which is the spatial autocorrelation coefficient a plausible value? I have read in a book that [Elhorst, 2014, P.14], ...
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0answers
64 views

Reducing “noise” in spatially regressed points

I'm working on spatial data on a grid. I have two variables that I think to be correlated and I would like to build a model (see Fig attached). I did some exploratory analyses following the ...
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0answers
401 views

How to check spatial autocorrelation correctly in a glm

I ran a binomial glm as below and from plotting observations i know that there are many observations close to each other and i expect them to be highly correlated. For this matter after selecting the ...
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0answers
142 views

Calculating Moran's I on large point dataframe in R

I have a dataset of about 77,000 points of which I want to test autocorrelation. I have tried to compute the test statistic using the testSpatialAutocorrelation tool in the DHARMa package, which uses "...
1
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0answers
219 views

Using Moran's I test for spatial autocorrelation on residuals from logistic mixed model?

I know that tests using Moran's I are not appropriate for binary outcome variables, but can I use that test on the residuals from a logistic mixed model to see if spatial dependence is unaccounted for?...
1
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0answers
136 views

How to properly address autocorrelation for logistic regression of spatial data

Background for the Model: https://stats.stackexchange.com/questions/268201/how-to-increase-mcfadden-score-and-choose-proper-predictor-for-binary-logistic-r Data I have: Forest loss points Forest ...
1
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0answers
64 views

OLS tool in ArcMap 10.4: Spatially Autocorrelated Explanatory Variable

I am performing ordinary least squares regression analysis on two variables: K concentration in soil as explanatory variable, and thickness of stalk of plants as the dependent. The K-concentration ...