Questions tagged [geostatistics]

Statistical modeling and analysis of georeferenced data, often modeling spatial covariance. An example is kriging.

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1answer
14 views

How to use regression of data linked in space and over time?

I have an R data frame, set up like so: ...
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1answer
44 views

Is the spherical covariance function not positive definite for d > 3?

I read in a textbook (Japanese one) that the spherical covariance function is only valid for dimensions $d = 1,$ $2,$ and $3.$ I have the following questions: Does that mean the spherical covariance ...
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Cokriging variances differ using cross validation

I'm investigating cokriging using various metals in the Meuse dataset but the variances output by R when I predict values at gridded points differ substantially from the variances produced by cross ...
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1answer
24 views

What are the possible machine learning models for this geospatial analysis task?

I am new to ML and have some experience with building CNN models. I recently got involved with a research project and here is the task I have to work on: I've been given some (latitudes,longitudes) ...
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33 views

Zonal statistics (mean± StDev) from polygons with different area

I am analyzing a temperature image using a land cover map with the overall goal to prepare a barplot where I report the mean ± StDev temperature for each land cover class. To do so I assigned each ...
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why variogram models take only one independent variable

lznr.vgm = variogram(log(zinc)~sqrt(dist), meuse) i am using meuse data for practicing to create variogram models, but i am confused to know there are 14 ...
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25 views

Correlating Two Time Series with Gaps in Data and of Different Lengths

I am attempting to correlate the time series from 4 separate tilt monitors that sample every 5 minutes. The time series have slightly different base times and end times, and the resulting arrays are ...
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13 views

Kriging with Weighted Data

I have a point-level dataset of apartment building level rent. I have the average rent per square foot per building and the number of units in that building. I would like to krige a surface of points ...
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1answer
41 views

Controlling for spatial confounding in point-referenced data

I have a point-referenced data set with 2 binary outcomes. The data shows a strong correlation between these binary attributes - however, the geographic clustering is also qualitatively clear. I would ...
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1answer
14 views

Finding the effect of nodes on a density heatmap

Let's say I have a geo-tagged dataset of all payment transactions for businesses in a city. I know whether each payment is made by cash or card, and have made a heatmap of where in the city the ...
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20 views

Statistical tests of significance for land use analysis: which one to choose?

I'm not an expert in geostatistics but I need to do a statistical tests of significance to understand which differences between studied categories are statistically significant. Here's the practical ...
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1answer
29 views

Return Period and Probability

My question is simple: If I assume that the probability to be hit by a lightning strike for a person in this year was 0.5 percent would it mean that if I was able to live 200 years I would be hit by ...
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23 views

Using Markov random field spatial weights to account for spatial autocorrelation

I am looking at the relationship between life expectancy and smoking rate within the London boroughs. I thus created a bayesx spatial regression model including a term which assigns spatial ...
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Considerations When Using Lat/Long Cords on Classifier

I'm interested in using Latitude and Longitude points as features to build a classifier model, but would like to better understand if I need to be taking any precautions when using Lat/Long cords in ...
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37 views

Can I create a test dataset with known errors to validate accuracy assessment? [closed]

I developed a procedure to measure the geometric accuracy of 3D building models based on the similarity to a 3D point cloud. Therefore I created mainly two quality criteria. The result of my automatic ...
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25 views

Statistical analysis of polygons QGIS : find areas of statistical difference

I have polygons for the country divided into E.D. areas. These polygons illustrate the average annual rainfall in their ED area. Is there any way to statistically tell if one polygon area has a ...
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1answer
72 views

How can I understand these variograms?

Using grf function from R package geoR, I simulated 6 replicates (each with 1000 samples) of a Gaussian random field on ...
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58 views

Spatial autocorrelation in 2sls regression in R

Is there a function in R which can be used to control for (geo)spatial autocorrelation in the data in a 2SLS regression? If there is no canned function, what other method can I use to calculate them?
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Anomaly detection with geo spatial data

I have geo spatial data. Dataset represents concentration of something. For instance, social media activity of people in point [time, lat, lon] I have some list of feature for every points (lat, lon):...
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Cerioli's modified test of indepence with spatial data

I have to two datasets $X$ and $Y$ with binary observations on a regular grid. A regular contingency test for independence would be flawed by the presence of spatial autocorrelation. Cerioli (1997) ...
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What is the nugget effect?

I don't understand exactly what is meant by the term "nugget effect" in geostatistics. When looking at empirical variograms plotting the variogram $\gamma(h)$ vs. the lag $h$, the nugget is defined as ...
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2answers
342 views

Temporal Variogram

Can we compute temporal variograms just like spatial variograms? I know about spatio-temporal variograms but I am more interested in doing a comparison of separate spatial and temporal variograms and ...
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1answer
77 views

How much data do I need in spatial hotspot analysis?

I'm now doing a project about spatial hotspot analysis. I read many literatures, however, I can't find any papers tell how they determine the data size they used. I mean, suppose we have crime ...
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1answer
110 views

How do you interpret this variogram?

Description: 8000 spatial data points spanned over an entire state 200 bins are used My question: Is the variogram telling something about the nature of the data? Why is it fluctuating? Should I do ...
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1answer
109 views

What is the best procedure to detrend data without loosing its anisotropy?

I wand to detrend some spatial data "A" with respect to two parameter "B&C". What is the best procedure to detrend A without loosing its anisotropy. Theoretically values of "A" should be ...
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1answer
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How to generate distance variable using street addresses [closed]

I have data of sold apartments. There is a street address for every apartment and I would like to generate a new variable that tells the distance from the train station. There are over thousand units ...
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1answer
354 views

Stationarity assumption for a point process

as I understand stationarity of a point process implies that it is invariant under translation. Imagine one has numerous realizations of the same point process. Due to the nature of this process, it ...
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1answer
284 views

What is the difference between accounting for anisotropy and trend removal when performing Kriging?

Without being geostatistician, I read a bit about anisotropy detection, mostly from ArcGIS documentation and the R gstat package tutorial. But still, it is hard to have a confident understanding of ...
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How to test for correlation between two weather station's data

I have about 15 weather stations, separated by quite a bit of kilometers. The data in these stations are the same for all, so is the resolution (daily). I want to try and find which of the stations ...
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79 views

What is 5th order kriging?

For our foray into geostatistics we got data that consists of measurements taken from the soil. The dataset has like concentrations of various different minerals. We were divided into a number of ...
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Explain Like I'm Five version for Variograms in R's gstat package

Long story short, I asked a question on StackOverflow about Variograms in the gstat package in R. The person who answered gave me some tips on creating the variogram using the package. My dataset is ...
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171 views

Interpretation of probability in geostatistics

In geostatistics, the concept of a random field is used in e.g. Kriging. Hence, at each point in your study area, there is a probability distribution. Should this probability be given a frequentistic ...
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type of continuity in geo-statistics

I am reading the book by Wackernagel, H. (1995) Multivariate Geostatistics: An Introduction with Applications and on page 49 The fit is done by eye because it is generally not so relevant how well the ...
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1answer
130 views

How to cluster trips, i.e. directed lines on a plain

I need to cluster transports/trips based on their start point and end point in longitude/latitude. I have about 5000 trips. Each has a starting point (lon/lat) and an end point (lon/lat). I computed ...
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1answer
127 views

Question about the Distance Weighted Sample Covariance

I recently got interested in spatial statistics. I had tried to get a distance based covariance matrix by using distance weight function and weighted sample covariance through this reference. I ...
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Clustering/pairing users based on multiple lat/lon values?

I have a data set that contains entities and lat/lon values for each one, potentially multiple lat/lon values. I believe that some of these entities may actually be the same person, although I can't ...
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1answer
139 views

How, in practice, are spatial covariances determined?

How, in practice, are spatial covariances determined? If one has a single realisation of some observed field, how can the spatial covariance ever be determined? Unless one has access to the many other ...
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112 views

What is the computational complexity of the empirical variogram?

If we use the method of moments estimator: $2\hat{\gamma}(h) = \frac{1}{| N(h) |} \sum_{N(h)} (Z(s_i) - Z(s_j))^2$ What is the computational complexity? My initial assumption was that it would be $...
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73 views

Is there an approach to combining variograms?

If we compute two seperate variograms for the same type of measurement, but the areas which they cover overlap, is there a logical way (or does it even make sense) to combine the two variograms? ...
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1answer
1k views

ML model selection for prediction of latitude and longitude

I am doing a project in which my aim is to predict the likely locations of a set of latitude/longitude points based on a couple of variables. Since I've never done any ML on locational data, which ...
3
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1answer
547 views

Using von Mises-Fisher distributions for geo-spatial machine learning

There's an interesting paper about predicting the geographical co-ordinates of Twitter users based on the kinds of words that they use in their posts. I'd like to do something similar that involves ...
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205 views

Predictive model with geospatial data

I have datas of random events with gps and time variables. I would like to compute probabilities of an event happening at a given time and location. In the training set, we have about 1500 possibles ...
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3k views

The right way to use Machine Learning to predict latitude and longitude

There are some simple ML techniques that can be used to easily predict latitude/longitude co-ordinates, such as predicting the latitude and longitude separately using two different models. However, I ...
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106 views

Do I need a special kind of linear regression for aggregated data?

I have two separate databases on individuals. But these individuals are not both present in the two databases. So I decided to aggregate them into area-level data (such as State-level). One of the ...
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93 views

Car out of route

I have one KML file that describes the movement of a car. Data comes from sensor in the car, contains wrong or noisy measurements. I want to filter the wrong measurements, i.e. throw away the ...
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Why likelihood based geostatistical modelling slower than non likelihood based counterpart

Likelihood based geo-statistics (geoR etc.) are usually slower than non-likelihood based geo-statistics (i.e. those based on just least square fitting, for example <...
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375 views

Combining probabilities for overlapping regions

For two regions which have independent probabilities of an event happening and share an overlapping region, what is the probability of an event happening in the combined region? I'm speaking of ...
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1answer
63 views

How to objectively decide when the value is stable?

Let's say that I've build models using three different values of some parameter (for example Max Tree Depth) in 1500 iterations. Right now, I want to decide after how many iterations the accuracy ...
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1answer
230 views

Spatial prediction on surface: very fine grid vs coarse grid + quick interpolation

Once I have fitted a spatial model (point-referenced data), I need to make a prediction map. A natural approach is to make prediction over a fine grid over the region. However, the required ...
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1answer
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What is the proper way of calculating the kernel density estimate from geographical coordinates?

I have to calculate the 2d kernel density estimate (kde) from a list of latitude and longitude coordinates. But one degree in latitude is not the same distance as one degree in longitude, this means ...