# 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.

67 questions
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### Why does including latitude and longitude in a GAM account for spatial autocorrelation?

I have produced generalized additive models for deforestation. To account for spatial-autocorrelation, I have included latitude and longitude as a smoothed, interaction term (i.e. s(x,y)). I've based ...
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### Is there an accepted definition for the median of a sample on the plane, or higher ordered spaces?

If so, what? If not, why not? For a sample on the line, the median minimizes the total absolute deviation. It would seem natural to extend the definition to R2, etc., but I've never seen it. But then,...
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### How can I simulate census microdata for small areas using a 1% microdata sample at a large scale and aggregate statistics at the small area scale?

I would like to perform an individual-level multivariate analysis at small levels of geographic aggregation (Australian census collection districts). Clearly, the census isn't available at these ...
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### 2D analog of standard deviation?

Consider the following experiment: a group of people is given a list of cities, and asked to mark the corresponding locations on an (otherwise unlabeled) map of the world. For each city, you will get ...
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### Trajectory clustering - preprocessing and algorithms

Context Consider the following problem where we have two time dependent (yearly) measures: Fertility rate Life expectancy And a dimension: country. In other words we have over two hundred "...
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### Volume of the 95% confidence ellipsoid

I'm dealing with 3D data that are the trajectory of a point over time. I would like to have an indication of how much it is "spread" in space and I thought about using the volume of the 95% confidence ...
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### How Does Kriging Interpolation work?

I am working on a problem in which I need to use Kriging to predict the value of some variables based on some surrounding variables. I want to implement its code by myself. So, I've went through too ...
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### Clustering spatial data in R

I have a set of sea surface temperature (SST) monthly data and I want to apply some cluster methodology to detect regions with similar SST patterns. I have a set of monthly data files running from ...
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### Model for population density estimation

A database of (population, area, shape) can be used to map population density by assigning a constant value of population/area to each shape (which is a polygon such as a Census block, tract, county, ...
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### Why is Moran's I not equal to “-1” in perfectly dispersed point pattern

Is wikipedia wrong...or I don't understand it? Wikipedia: The white and black squares ("chess pattern") are perfectly dispersed so Moran's I would be −1. If the white squares were stacked to one ...
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### Assessing error of a spatial interpolation algorithm

I have a set of 3D points. The points have three components $x$, $y$, $z$. You can think of these points as the surveyor points that one collects from measuring a terrain for GIS purposes. I have a ...
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### Smoothness of a surface

I am currently working on a model which takes two parameters and produces a measurement statistic. Think of it as Z = f(X,Y). Z is a matrix of my statistics and I am creating a surface plot of it in ...
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### Regression on the unit disk starting from “uniformly spaced” samples

I need to solve a complicated regression problem over the unit disk. The original question attracted some interesting comments, but no answers unfortunately. In meantime, I learned something more on ...
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### What is the interpretation of eps parameter in DBSCAN clustering?

I want to cluster lat-long data such that all clusters formed will have radius<=1000 meters Questions What is the actual meaning of eps parameter? Please given an example. Will setting eps=1000 ...
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### Are there models for “censored” spatial point processes?

This is a problem I'm encountering in the context of analyzing a data set comprised of all crime locations in a city over a fixed time interval, although it could potentially arise in other types of ...
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### Combining multiple similarity measures in hyperspectral images?

I have a hyperspectral image where the pixels are 21 channels. So each pixel $\in \mathbb{R}^{21}$. I want to perform clustering on the pixels with similarity defined by two different measures, one ...
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### Why is Moran's $I$ coming out greater than $1$?

Moran's $I$ statistic is defined to be the quantity $$\frac{N}{\sum_{i,j} w_{ij}}\frac{\sum_{i,j}w_{ij}(X_i-\bar{X})(X_j-\bar{X})}{\sum_i(X_i-\bar{X})^2}$$ where $w_{ij}$ is some matrix of spatial ...
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### 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 ...
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### Software for making semi variograms and analyses?

Our lab used to have a program called GS+ that let us make semi variograms on our data and analyse them. Unfortunately, the licence has expired. Is there another piece of software that lets you do ...
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### Ripley's K Function and L Function for Point Patterns

The following is a spatial point pattern: and these are the corresponding Ripley's K function and L function for this data: How are these functions interpreted?
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### Problems estimating anisotropy parameters for a spatial model

I am looking for someone with experience in how to handle the anisotropy-parameters in the likfit() function which is part of the GeoR package in R. I am using <...
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### Can you use a spline function of the spatial coordinates to control for spatial autocorrelation? [duplicate]

Possible Duplicate: Why does including latitude and longitude in a GAM account for spatial autocorrelation? I am interested in the effect of a predictor vector $X_i$ on a binary outcome $Y_i$, ...
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### Using Anselin Local Moran's I Values in Regression

I am doing a multiple linear regression of factors related to poverty and would like to include some spatial-statistical data. I have come up with Anselin Local Moran's I values (cluster/outlier) data ...
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### Valid method to analyze spatial correlations in images?

Is there a reasonable way to quantify the amount of local correlations in an image? For example, I want to justify the correlations between a neighbourhood of pixels is much higher than the ...
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### How to compare two spatial points patterns in R?

I have two spatial points data sets (relocations of animal A and distribution of plant B). How can I investigate if animal A is more likely to be where plant B is present? With the animal ...
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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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### beta-regression accounting for residual spatial auto-correlation in R

I have data on the interval (0,1), that I model using beta regression with the betareg package in R. This works well. However, I ...