# 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.

19k views

### Tutorials to handle spatial data in R?

Does anyone know some good tutorials to handle spatial data in R? I know that there are some packages like rgdal and maptools but I haven't actually found usefull tutorials to get in touch with the ...
17k views

### Open source methods for kriging?

I have a point dataset which I'd like to Krige, ideally using an open-source software package. If possible, I'd also like to choose the semi-variogram model during the process to improve the ...
9k views

### How to compare two spatial point patterns?

If I have two point pattern distributions within the same geographic region, how would I go about visually and quantitatively comparing those two distributions? Also assume I have many points within ...
4k views

### How can I conduct Geographically Weighted Principal Component Analysis using ArcGIS, Python and SPSS/R?

I am after a description/methodology for conducting a Geographically Weighted Principal Components Analysis (GWPCA). I am happy using Python for any portion of this and I imagine SPSS or R being used ...
15k views

### How to cluster spatial data in R?

I am very new to R. I have bunch of data points with latitude and longitude. I want to use R to cluster them based on their distance. I have already taken a look at this page and tried clustTool ...
4k views

### Using R with ArcGIS Desktop

In response to comments below, a re-phrasing of the question. I've used the integration of R with QGIS, and found it a very uesful tool. Having taken a look at the R toolbox extension for 9 and the ...
2k views

### Robust alternatives to Moran's I

Moran’s I, a measure of spatial autocorrelation, is not a particularly robust statistic (it can be sensitive to skewed distributions of the spatial data attributes). What are some more robust ...
671 views

### How can I statistically calculate the “real” road from a set of GPS tracks

I participate in a long-distance cycling club, and we started to collect GPS data routinely from our riders. My interest is to calculate "the real trajectory" for future events based on accumulated ...
676 views

### Calculating Focal Statistics for Special Neighborhood?

I'm looking to calculate focal statistics for each cell of a raster, within a neighborhood of a specified criteria. Background - I have three binary rasters, each representing a single vegetation ...
4k views

### Spatial statistics software for GIS?

I am searching for spatial statistics software which has many powerful features and supports a GIS interface. Can anyone give me some advice?
2k views

### Learning Spatial Statistics

I have a significant background in statistics, and I'd like to learn more about spatial statistics (and statistics associated with geospatial data). Are there any especially good resources for ...
4k views

### Using R with ArcGIS for Desktop (without using GME)? [duplicate]

I am trying to learn R generally and making statistics for maps. I found some useful tricks for making maps with it but it is not the best you can do. My everyday GIS program is ArcGIS. How I can use ...
798 views

### Ecological geospatial conundrum

I am looking for a different, more elegant solution to a spatial statistics problem. Raw data consists of an x-y coordinate for each individual tree (i.e. converted to a point .shp file). Although ...
785 views

### How to determine if trees within forest gaps are clustered?

The attached dataset shows approximately 6000 saplings in approximately 50 variable sized forest gaps. I am interested in learning how these saplings are growing within their respective gaps (i.e. ...
902 views

### Are Zonal Statistics possible in PostGIS2?

Now with postgis2 which supports rasters by default is it possible to do a zonal statistics analysis? I've google it but I haven't found anything solid? Is there a tutorial outthere to get me ...
2k 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 ...
773 views

### How to associate polygons with the nearest point on a point layer? (Or … how do I assign a postal area to a salesman?)

I have a polygon layer of postal code areas and I want to use them to create sales territories based on where our sales people are based. So I assume that I need to work out for each of the polygons ...
4k views

### Is there a Free Aggregate Points tool out there for ArcGIS 10?

I need to do some Getis-Ord analysis but first I need to aggregate my points. I know of XToolsPro, but the aggregate points function is locked and you must purchase a license to use it. I am ...
451 views

### How to create an error map to support an average kernel density map?

I've created an average kernel density map by running KDEs on points stacked within the same spatial extent. For example, say we have three point shapefiles representing seedlings in three different ...
7k views

### How to find Clusters of N Points Within X Distance?

We have tried two methods of cluster analysis: Cluster and Outlier Hot Spot ... but neither meets our specification which has these 3 parameters: a Set of Point features N points within a ...
2k views

### Calculating mean slope: Harmonic or Arithmetic Mean?

I have to calculate the average upslope percent slope for a large dataset, the basic method is detailed here. However, I've begun to wonder if harmonic mean might be more appropriate than the ...
3k views

### how to overlay shapefile and raster?

I have a shapefile with polygons. And I have a global raster file. I want to overlay the shapefile's polygons onto the raster grid and calculate the mean raster value for each polygon. How can I do ...
34k views

### How to convert zip codes to latitude and longitude?

I have a data set that includes a list of zip codes. Is there a way in R to convert these zip codes to latitude and longitude coordinates?
3k views

### How to Find the Average Raster Value of an area defined by a shapefile using R?

I have a set of raster images which represent a specific month over the years, and I want to make a timeline of the average values of an area using a shapefile. How do I extract the values from the ...
1k views

### Comparison of three contour lines

I am looking for a way to spatially quantify the difference between three contour line shapefiles. More specifically, I have two elevation rasters which I intend to create contour lines from, but ...
5k 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 ...
319 views

### How to find the most spread out locations?

Probably a very simple question. I have a list of about a thousand potential geographical locations (lat lon), and of those I need to select the 200 locations that are "most spread out". I think that ...
662 views

### How to quantify unevenness of polygon boundaries?

I have two polygons: Polygon 1 and Polygon 2. Using two metrics, area and perimeter length, I want to express quantitatively that Polygon 1 has a more uneven/jagged/irregular perimeter than Polygon ...
534 views

### Calculating spatial correlation between features from two separate layers in QGIS

I am trying to determine whether the presence of large numbers of active duty military troops in an area is spatially correlated with higher/lower levels of violent crime. That is, are the areas ...
222 views

### Visualization to inference workflow

I provide statistical support for a public health department. As you might imagine, we put together a lot of maps on a regular basis. For me, maps are just another kind of data visualization - ...
892 views

### Compare spatial cluster/agglomeration patterns for polygon data

I have agricultural data in form of polygons which I would like to test for spatial clusterings/spatial agglomerations. All in all I have about 40 variables which I can aggregate and standardize in ...
10k views

### Joining polygons in R

I am wondering how to join spatial polygons using R code? I'm working with census data where certain areas change over time and I wish to join the polygons and the corresponding data and simply ...
2k views

### Determining statistical relationships between rasters using R vs ArcGIS Desktop?

I am trying to analyze how sets of rasters relate to each other using some statistical techniques. As, I don't have much experience using the spatial statistics tools in ArcGIS I was exporting my ...
1k views

### How to cluster points based on a kernel density?

I have a large dataset with 36k points representing commercial land uses, each with a field containing the square footage. I have run a kernel density analysis on this dataset, producing a raster ...
2k views

### In ArcGIS Is there a tool that will select a percentage (75%) of a whole group of points based on the distance from one separate point?

This is ArcGIS specific. I have 2 point shapefiles A and B, the first one (A) is a single point that contains a lat long, the second (B) is a multitude of points (over 12k) that each contain their ...
3k views

### Spatial statistics tools : clustering analysis on raster data

I've an apparently simple problem, but i can't find a clear methodology to use. I'm tasked to delimit "urban areas" by vector convex polygons, using the Gridded Population of the World dataset from ...
273 views

### spatial and spatiotemporal analyses

I have a dataset that consists of 247 mosquito traps placed in fixed positions and sampled weekly for 23 weeks. I also have dengue disease incidence data (indexed to home address) during the same time ...
415 views

### (How) do the modifiable areal unit problem and modifiable temporal unit problem interact?

I am reconstructing historical time series of land use and other related data from a variety of sources with different spatial and temporal resolutions and would be interested in what possible (hidden)...
1k views

### Modifying Bivariate Moran's I /LISA to include self?

I am using GeoDa's Bivariate Moran's I function to examine patterns of collocation between two variables at the county level (call them A and B for now). I know that, having run the analysis I can ...
2k views

### How to implement bivariate Ripley's K function?

The attached image shows a forest gap with red pine represented as circles and white pine represented as crosses. I am interested in determining if there is a positive or negative association between ...
195 views

### Approximating GPS coordinates for a point from n expected locations

I'm trying to find the coordinates of my point of attention (point X,marked blue). I used the GPS device of my car to collect the coordinates according to where I parked my vehicle each time I visited ...
640 views

### How to calculate purchasing power on postcode level?

Does anyone know of an algorithm to calculate purchasing power on a postcode level? What source data is needed? Purchasing power on admin. level, population?
263 views

### Which spatial weighting function does ArcGIS' GWR use?

I am running Geographically Weighted Regression and originally was using ArcGIS to carry out the analysis until I read/heard mixed reviews about it. I have now tried a different programme to run it (...
2k 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'...
361 views

### How to compare spatial patterns (crime cases vs population)?

I am looking for a way to statistically compare two spatial patterns in shape polygon data (not point pattern analysis). Let's say I have a city map divided in neighborhoods (barrios), in shape ...
368 views

### How can I calculate Moran's I in 3D?

This may be a question to post on a GIS forum, but I was wondering if among the spatial data experts here, someone could help me calculate the extension of Moran's I to 3D? Our data is about 3D ...
688 views

### Confidence interval from raster data

I have raster data that represents a probability distribution, i.e. each cell has a probability value (in my case the probability that an animal may be found in the cell), and all the cells add up to ...
1k views

### Spatio-temporal block kriging with R package gstat?

In the documentation of sp I saw that the coords argument of the SpatialPolygons function only accepts 2 columns. Is it not possible to create 3-dimensional polygons? I am doing spatio-temporal ...