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.
26
votes
7answers
5k 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 ...
22
votes
2answers
808 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 ...
19
votes
6answers
2k 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 ...
17
votes
6answers
679 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 ...
14
votes
3answers
2k views
R to ArcGIS 9.3.1 or 10
I m 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 ...
14
votes
3answers
510 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 ...
13
votes
1answer
688 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 ...
12
votes
3answers
275 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. ...
11
votes
7answers
959 views
Best 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?
11
votes
1answer
164 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 ...
10
votes
2answers
1k 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 ...
10
votes
5answers
243 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 ...
10
votes
3answers
2k views
How to cluster spatial data in R?
I am very new to R, so please bear with me : >
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 ...
10
votes
1answer
148 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 ...
10
votes
2answers
284 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 ...
10
votes
1answer
2k 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 ...
9
votes
2answers
800 views
How to get the second nearest neighbor between two point patterns in R?
Is there a way to get the distances for the second nearest neighbor between two point patterns in R? The spatstat package has a function called nncross but it only applies to the nearest neighbors ...
9
votes
1answer
223 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 ...
9
votes
3answers
205 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 ...
9
votes
1answer
190 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 - ...
9
votes
1answer
130 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 ...
8
votes
4answers
922 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 ...
7
votes
5answers
423 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?
7
votes
1answer
101 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 ...
7
votes
2answers
573 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 ...
7
votes
3answers
713 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 ...
7
votes
1answer
226 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 ...
7
votes
1answer
96 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 ...
7
votes
0answers
181 views
Can I modify the 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 ...
6
votes
4answers
463 views
statistics by rectangle (raster image)
I have a shp file with some rectangles and I want to extract statistics within these areas from a raster image. I prefer ArcMap 9.3.
6
votes
2answers
1k 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 ...
6
votes
1answer
69 views
What does shading indicate in home range plot?
I've simulated a home range in R using the clusthr function from the adehabitatHR package. The home range is made from 50 x,y coordinates. The output is attached.
I'm trying to get clear on what ...
6
votes
2answers
2k views
How to do regression analysis between two variables using ArcGIS
I have a temperature image (interpolated from climatic point data) and NDVI data at the monthly interval. I need to do correlation analysis between temp and NDVI. Is it impossible to do this using ...
6
votes
1answer
149 views
how to aggregate the rates, represented by points, within X radius
the point represents rates like 10%, etc. (this was also pretty clear from 2 years ago) -- been trying to do this for 2 yrs...
the points dont represent numbers of events since they are rates ...
6
votes
1answer
149 views
Calculating “relative slope” per Mora-Vahrson method in ArcGIS
I'm a longtime lurker who finally decided to register on the forum (in no way driven by my need to have a certain question answered, of course...).
I was contacted by a colleague asking for help ...
6
votes
2answers
177 views
How do I process xy data to be compatible with census block data (so I can include them in my GWR model)? (ArcGIS 10)
I'm pretty new to GIS, so apologies if my problem is rather simplistic
I'm planning to do regression analysis (GWR) on several datasets, where all but one is based on census areas (UK OS lower level ...
6
votes
1answer
263 views
Normalizing and adding kernel density rasters
I have 4 years of road kill data for one road, though each year has a different sample time frame (i.e. May-June vs. April-October) and therefore each year has a different number of surveys and totals ...
6
votes
2answers
207 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 ...
6
votes
2answers
466 views
What are best practices to compare densities and locations between two sets of points?
I have two sets of point shapefiles. They represent two different customer groups for a retail store. Shapefile A represents online customers, Shapefile B represents in-store customers.
What I ...
5
votes
4answers
5k 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?
5
votes
2answers
383 views
How to implement bivariate Ripley's K function in ArcGIS 10?
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 ...
5
votes
3answers
1k views
Statistical relationships between rasters
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 ...
5
votes
1answer
738 views
QGIS Data Management: How to calculate Standard Deviation?
does anyone know of a way to find the standard deviation of an attribute lying within any given polygon? The plugin dialog "Join Attributes by Location" gives only the options Mean, Min, Max, and Sum.
...
5
votes
1answer
99 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 ...
5
votes
3answers
169 views
How to test spatial correlation between two point layers
I have two point layers, which visually have spatial correlation. I'd like to test it but wonder if there is such a method or index？
5
votes
1answer
210 views
Spatial regression
I have a question regarding performing spatial regression on data which residuals are spatially correlated.
If the residuals are spatially autocorrelated due to the presence of trend, how should I ...
5
votes
1answer
162 views
Spatial graphing, distribution of polygon area over latitudes
Given a polygon in a PostGIS database, what is the best way to create a graph of its distribution over a range of latitudes? I'm picturing a graph of a curve, where the proportion of the total area ...
5
votes
2answers
149 views
Spatial Analysis with Factors/Classifications
When doing analysis on spatial data with associated information that is numeric, it is possible to use techniques such as Kriging or Interpolation or Cluster Analysis to find out interesting ...
5
votes
1answer
388 views
Trouble with Hot Spot Analysis (Getis-Ord Gi*) tool in ArcGIS
I am trying to locate areas with a high rate of accidents involving bicyclists or pedestrians per car accident of any kind. I have a point file of accidents and a point file of all those with ...
5
votes
3answers
540 views
Select maximum number of points more than x meters apart
I have a dataset of ~15,000 points that are locations along ROV survey tracks where measurements were taken. These points can be less than 5 meters apart and the survey tracks often cross or can be ...
