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
1k views

Why are Low Values showing as hot spots?

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
271 views

PostGIS: ST_Equals false when ST_Intersection=100% of geometry?

I have 2 datasets consisting of cadastral parcel data - roughly 125,000 rows each. The geometry column is WKB polygons representing parcel boundaries; all data are geometrically valid (the polygons ...
1
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0answers
20 views

Verifying time-invariance for spatial gradients of air pollution?

I have data from a network of NO2 passive samplers. Measurement are repeated in the same positions in different years. I need to verify if spatial gradients in air pollution remain constant in time, ...
7
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1answer
252 views

Interpolating points observed with different time duration

I am doing spatial interpolation with a group of points. Some points have complete observation of events: for a period of 24 hours we have observed N events in each point. These points have N ...
1
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1answer
190 views

Interpolating lots of points with seemingly good spatial density

I'm using Arcmap 10 and I have scattered points (denser in an area). Each point represents a thickness value of a simulated avalanche deposit. I want to get a raster from this points which I will ...
5
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1answer
146 views

Kriging to calculate forest biomass?

I am trying to create biomass map using Kriging from ground sample point. I have about 150 and 53 point plot for dense and sparse strata. The data is not normal so I have transformed it. After ...
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0answers
62 views

Kriging metal concentration with irregular set of sample points

I need to perform some interpolation to map a metal concentration around a platform. The distribution of my stations is not regular (see figure below where stations are the green points labelled with ...
16
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5answers
10k 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 ...
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2answers
61 views

Low point density analysis

I'm working on a project for a conservation plan. Part of the plan requires that areas added for conservation have less than one structure per five acres (these are pretty large, mostly undeveloped ...
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2answers
2k views

how to do change detection in ERDAS

I'd like to ask a really simple question. I want to obtain the size of unchanged, decreased, and increased area etc (just like shown in image below) from 2 classification images in 2000 and 2007. How ...
0
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2answers
36 views

Arcgis 10-Sample selection

I am using arcgis 10 and I would like to select (in a manner of well spatially distributed) some of the polygons included in a .shp as testing population for a statistical analysis. The rest of the ...
1
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0answers
76 views

Optimal distance and power exponent in IDW

I want to apply IDW interpolation for my region of interest, and through leave-one-out cross validation I want to find the optimal values for the distance parameter and the power exponent. I know that ...
2
votes
1answer
110 views

Sublayers or Multiple Visualizations for CartoDB

I'm trying to learn a bit of CartoDB by creating a heatmap using crime data available on the city's website where the raw number of crimes are displayed for each police district. So far I've been ...
32
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7answers
13k 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 ...
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0answers
46 views

Problem with ST_SummaryStats, ST_Buffer, and casting between geometry/geography types

I have a test raster that covers the world ((-180 90), (180 -90)). The SRID is WGS 84 (EPSG:4326). Values for cells in the north-western quadrant ((-180 90), (0 0)) are random integers in the range 1 ...
0
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1answer
113 views

Mean Center/Median Center tool providing points mathematically centered but physically appearing in the wrong location

To create population weights, I'm using the Mean and Median Center tool to find the center of our populations in census tracts. However, I've noticed that some of the points that are popping up are ...
1
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0answers
74 views

Using Ripley's K Function in ArcGIS for coral density along a transect?

I have some data from transects taken in a mangrove system. I want to analyze the spatial distribution /some sort of spatial statistics of how clumped/dispersed corals are along this linear transect. ...
1
vote
1answer
100 views

resize map and add points to it using R

I am working with spatial data UK. The map is plotted here. I want to resize the map and make it bigger and clear! here is my code LA <- readOGR(dsn =".", "infuse_dist_lyr_2011_clipped") ...
0
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0answers
17 views

scenarios to make multiple data maps comparisons?

I'm using Leaflet (and several of its plugins) to make a custom SOLAP solution and i want to offer to the user, the possibility to make data analysis and comparison between multiple maps, my question: ...
4
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3answers
261 views

How to find buffer radius around raster cell that covers a defined sum of raster cells?

I want to do a neigbourhood analysis on some raster data. I need to know how big a circle around each raster cell must be to include a certain amount of specified raster cells. Let's say that for ...
0
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1answer
586 views

how to choose stratified random sample on multispectral image

I'd like to choose random samples from multispectral image according to each Land Cover image. The multiband image has 70 bands representing land surface temperature data from MODIS. Land cover image ...
2
votes
1answer
1k 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: ...
2
votes
3answers
267 views

Summarize the total area of land use polygons within map sheets - how?

I would imagine that at least some of you have encountered similar problems to mine and I´d like to hear how you solved them. I have a map sheet index (a grid as a shape file) covering a large area. ...
3
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1answer
302 views

Dissolve Polygons using R / join specific polygons

I have data in shapefile format :: UK_boundaries I am new to R and Spatial data as well, I am trying to join some areas to be as one area no line(s) between them. Based on my search I understand ...
4
votes
1answer
1k views

Interpolating Maps - Statistical Learning Techniques vs Spatial Statistics Techniques

I have recently begun experimenting with the interpolation of variales over a whole country. I have good sized training set where I have several dependant variables (continuous and categorical) ...
6
votes
1answer
131 views

Creating forest patches from land cover layer?

I have a land cover layer from which I've extracted the tree canopy class and set all values that are not tree to NULL. I've also converted it to a vector and exploded it to make single part features. ...
1
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3answers
59 views

Selecting Features and Averaging Attributes

I currently have two point shapefiles, SHP A with approximately 75 points and SHP B with approximately 2000 points. What I would like to do is: 1) For each point in SHP A I would like to find the ...
2
votes
1answer
477 views

Accounting for Spatial Autocorrelation in ZINB Model?

I'm doing an analysis on disease in Chile. I'm using the rate as the Dependent Variable and both remote sensing and housing-type data as the Independent Variables. I have several questions regarding ...
2
votes
1answer
193 views

Incomplete intersection area using gIntersection in R

I have two SpatialPolygonsDataFrame, one of them is the deforested area in the Amazon and the other is the city of Vila Rica, which is in the same region. I would like to calculate the total ...
0
votes
1answer
126 views

Testing correlation between two polygon features

I am working on a project looking at county boundaries for the state of California. I have 2 polygon datasets with this same geographic boundary, and these datasets, when mapped individually, visually ...
4
votes
1answer
5k 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 ...
4
votes
1answer
808 views

How to split a polygon using R

I have an irregular polygon which is a spatial object. I want to divide it into multiple polygons (say, n=25) with equal height. To show how I want to divide it, I've plotted grids on the ...
1
vote
1answer
91 views

mathematics of spatial diffusion models

There are different types of spatial diffusion such as contagious model, migration model, etc. What are the good books to learn about the mathematics behind these spatial diffusion models?
2
votes
1answer
85 views

Kernel density estimation across multiple UTM zones

I'm trying to compare the spatial distribution between two groups of fishing locations (for each of several different years) in the Bering Sea (lat's ~53 to 65N, long's ~ -178 to -158W. My preliminary ...
0
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2answers
53 views

ArcGIS compute nearest network neighbour for each point

I have a set of points and I would like to calculate a value for each point to indicate how 'clustered' to other points that point is. Distance to nearest neighbour (through a network) would do fine. ...
1
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0answers
132 views

R package spatstat: How to use point process model covariate as factor when pixel image values are numeric

I am trying to model a point process with an image covariate using the ppm() function in the spatstat package in R. I convert my raster to an im object for use with spatstat, and I run into a problem ...
5
votes
1answer
1k 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
1answer
93 views

ArcGIS Spatial Statistics: Distance to 3rd/4th/5th closest feature

We have an algorithm which requires us to produce a score based on the distance from any given cell in an output raster to a score calculated from the distances of the 3rd closest, 4th closest, and ...
0
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0answers
17 views

implement aspect in least cost path analysis to account for downhill and neutral ground movement [duplicate]

I am creating a least cost path model for large species that migrate over large distances across a rugged landscape (elk, deer, etc.) To calculate movement cost I am using a slope raster but I ...
0
votes
2answers
231 views

Test for spatial randomness with Ripley's K or L function in R

I have a spatial point pattern that I would like to test against complete spatial randomness. I managed to plot a Ripley's K function for my data and a function for a random distribution with a ...
9
votes
4answers
24k 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?
2
votes
1answer
431 views

How to interpolate GPS data correctly?

I'm working on a project that involves using linear interpolation to fit lines to lat/lng points. I'm pretty new at scientific programming related stuff, and I was wondering if people could steer me ...
4
votes
0answers
103 views

Search Radius for Line Density

I have been working with GIS for many years but I am fairly new to the spatial analyst side of things. I am working with many satellite tracks for many different individual animals and would like to ...
3
votes
0answers
106 views

Statistically comparing two sets of coordinates [closed]

I have been given a task to compare two sets of points, one set being a set of predetermined points, on the other being a set of actual points that were taken in the field. I have to compare these ...
1
vote
0answers
107 views

Extract mean value of a raster into a grid shape file [closed]

Hello guys I need your help I have a soil map of an island and a Grid polygon. I want to extract the mean value of the soil map to polygons squares of grid. I read this and this but Ι can't find the ...
0
votes
2answers
70 views

spatial relation between springs (points) and geological faults (polylines)

In ArcGis 10.1 (advanced license), I have digitized the geological faults (polylines) and the location of water springs (points). Since, relying on literature, there is a potential connection between ...
3
votes
0answers
136 views

How to deal with data which are not normally distributed when kriging?

I'm a novice with advanced spatial interpolation, and I'm trying to use the Geostatistical Analyst to interpolate a surface based on borehole data, using Ordinary Kriging. The help file explains how ...
0
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0answers
103 views

QGIS nearest neighbor parameter description

Could anyone explain me the following parameters, which I get by doing a nearest neighbor statistic on a point shape? I suppose that Observed mean distance is the mean distance between two points ...
10
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2answers
3k 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 ...
1
vote
1answer
41 views

How to Predict demand on a bus route, considering variaton in kms and price?

If there is a route (line) modification, I mean change on distance; and also a change on the price for the user. How can I calculate the demand on the next year, considering seasonnality. What would ...