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.

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1answer
133 views

How can I multiply each band of multiband image by separate scalars?

I have an image with 5 bands. I need to multiply each band of this image by different scalars one time (I'm lazy to do it one by one) and then get multiband image as a output. For example ...
5
votes
2answers
629 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 ...
10
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1answer
304 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 ...
2
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1answer
190 views

Obtain normalized raster average per polygon?

I have a raster that contains percentages of total forest killed plus a polygon layer that defines different zones. My goal is to find a good statistical representative that describes the forest ...
4
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1answer
568 views

How to write values from arcpy statistical output to table?

The attached script is my stalled attempt to perform the following workflow: Create a table and create fields Loop through a folder of point shapefiles and perform average nearest neighbor analysis ...
6
votes
1answer
421 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 ...
2
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1answer
120 views

What are the geometric principles and GIS techniques that I can use to generate a postcode coverage of my city at street scales?

Postal codes of Brazil and another countries are oriented to distribution logistics, and improvement of reliability in writing the postal addresses; but without much concern for the spatial ...
3
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0answers
240 views

How do I access layer attributes from within QGIS' manageR plugin?

This is probably a fairly basic question, but searches for manageR come up with a lot of noise, and there's no manageR tag. What I'd like to do is load the attributes from a particular field of a ...
7
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4answers
10k 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?
14
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3answers
470 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. ...
9
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2answers
1k 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 ...
2
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0answers
125 views

How are geographic coordinates stored for multivariate statistical analysis? [closed]

In terms of Principal Components Analysis or Multiple Discriminant Analysis, I have used dummy variables to represent a group of like-features that are located in the same geographic region. For ...
11
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1answer
306 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 ...
4
votes
2answers
617 views

Spatial query of raster data

I have population distribution data as a raster layer and exposure contours as vector (polygon) layers. What I'd like to do is use the vector layer to estimate the population indicated from the raster ...
1
vote
1answer
216 views

How to fit a polygon to a “best buffer” about a reference geometry in it?

If I have a polygonal geometry gbase, like a street (a rectangular strip), and a reference geometry gref, like a central line of gbase. The question is what is the function (here named BestBuffer) ...
8
votes
1answer
439 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 ...
2
votes
1answer
732 views

Defining datum for Lambert Azimuthal Equal Area and converting to geographic coordinates

I posted this question to a specialised mailing list for spatial data analysis using R here but didn't recieve a response. I am working with shapefiles and rasters in R, and I am unsure if I am ...
4
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2answers
625 views

How to find the watershed for each outlet point and sum values within it?

I have the following files to work with: Stream network of a basin; Outlet points for each segment* of the network and Points which represent water withdrawals along of the stream, which are not ...
1
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1answer
643 views

Modelling Sea level rise scenarios for a Coastal county in ArcGIS

I am a graduate student @ Clemson University and am working on a GIS based project which is to model different sea level rise scenarios and estimate its impacts on a coastal county and to suggest ...
8
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2answers
1k 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 ...
4
votes
1answer
230 views

Regression with Nominal and Categorical Data

I am doing a project looking at the prevalence of a weeds in an area. As an example, I have the following layers: Weeds Layer (polygons) {categorical data} Each polygon represents a point or polygon ...
5
votes
1answer
267 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 ...
14
votes
3answers
591 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 ...
2
votes
1answer
900 views

Outputting results message from spatial statistics tool to text file using python

I'm using the following tool in ArcGIS 10 - Calculate Distance Band from Neighbor Count (Spatial Statistics). I'm using a python script to execute this tool several times on different shapefiles: ...
6
votes
2answers
276 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 ...
2
votes
1answer
762 views

Hotspot Analysis: Low Values showing as hotspots

Im running hotspot analysis on point data, attempting to examine pollution emissions. I ran spatial autocorrelation first in order to determine the default distance threshold to use in the fixed ...
4
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2answers
690 views

Gaussian Plume Model

I'm looking for code to implement a gaussian plume model in 3D. Any suggestions on where to start? Are there any python scripts out there? Thanks
4
votes
1answer
282 views

Finding intersection density for weighted lines connecting points across the continental USA

I'm working on an one-time problem that I'm hoping to solve with a computer program using free GIS libraries (preferably for VB.Net, C#, or Python... Java or C/C++ could work too). Alternatively, I ...
16
votes
1answer
1k 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 ...
5
votes
1answer
205 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 ...
4
votes
1answer
409 views

Analysing Information By Vector Grid

I have two vector line datasets and wish to compare the line lengths. While I have already compared the sum of the lengths, I'd like to conduct further analysis down to 250m, possibly lower. I'm ...
5
votes
3answers
1k 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 ...
9
votes
1answer
269 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 ...
4
votes
2answers
593 views

comparing two TINs

i have the following two files: 1) LiDAR las file1 2) Let's give it a name LiDAR las file2, contains the same file1 data, where number of points randomly removed. So if file1 contains X number of ...
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0answers
152 views

ESRI Silverlight Cartography - Looking at whats not there

I have line data that has been symbolozied in ways that I don't have time to understand and would like to make a map that tells me =). My general question is how to display the lack of data results ...
6
votes
2answers
359 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 ...
4
votes
0answers
96 views

Which spatial statistics tools to use in examining autocorrelation in two layers? [duplicate]

Possible Duplicate: How to compare two spatial point patterns? I am working on a project and have found myself a bit lost as to which types of Spatial Statistics tools I should use to get ...
6
votes
2answers
778 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 ...
4
votes
1answer
566 views

Simulation envelopes and significance levels

Many spatial analysis packages provide Monte Carlo techniques to simulate upper and lower “envelopes” for a summary statistic as a function of distance (e.g. K-function, nearest neighbor, etc…). ...
3
votes
1answer
352 views

Splitting raster pixels by a polygon's edge?

I have a a polygon shapefile of different regions, and a raster grid of precip data. I want to take the polygon and add up all the raster precip data in each zone. I could use zonal statistics to do ...
2
votes
0answers
112 views

Training courses in geostatistics and spatial modelling [duplicate]

Possible Duplicate: What are sources for current geo-statistical analysis classes/events: open or proprietary Does anyone know of or have been on any training courses that specifically ...
2
votes
2answers
282 views

Choosing an aggregation strategy that will be spatially represented on a google map

I'm under an NDA so I cannot really get into specifics of what I am doing. But, suffice to say, I am taking a large amount of spatially-acquired data and drawing this data onto a Google Map surface ...
10
votes
2answers
2k 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 ...
6
votes
1answer
359 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 ...
7
votes
3answers
953 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 ...
1
vote
3answers
1k views

How to count pixels of a raster in polygons using QGIS?

I need to compute some statistics of the pixels of a given raster that are coincident to the polygons of a vector file. Is there a simple and effective way to do this in Quantum GIS or similar?
6
votes
2answers
4k 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 ...
5
votes
1answer
922 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. ...
7
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5answers
480 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?
8
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4answers
1k 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 ...