Collecting and analyzing numerical data or making numerical summaries of data.

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25 views

How to combine Polygons and points?

Sorry for the basic question. I'm using qgis. I have two layers, one with points (a file that contains addresses with latitudes and longitudes linked to several variables), and another layer (a ...
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1answer
15 views

Intersect shapefile with raster, then determine proportion of each raster value?

Using the arcpy module in Python, I want to find the proportion of each pixel value within the boundary of an overlaying polygon. (The polygon is in a shapefile.) For example, there are 10 possible ...
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3answers
50 views

Is it possible to calculate statistics across multiple fields in arcpy?

The summary statistics command can be used in arcpy to calculate statistics - this tool runs against a single field, eg: SUM—Adds the total value for the specified field. Is there an ...
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2answers
2k views

Is there a zonal statistics tool to calculate median and mode raster values for each polygon?

I'd like to calculate zonal statistics for a raster where the zones are defined by polygons in a vector layer within QGIS. Specifically I'm interested in calculating the median and mode raster values ...
3
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2answers
48 views

How are kappa and overall accuracy related with respect to thematic raster data?

I recently calculated kappa (using confusionMatrix{caret} in R) between a thematic raster dataset at 1m spatial resolution and another at 30m spatial resolution. I was interested in quantifying the ...
2
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0answers
280 views

On using R data with ArcPy to make histogram in ArcMap

I am writing a tool in python which passes parameters to a R script, which in turn creates a DBF file. I read this DBF and want to make a histogram out of the data inside ArcMap as one of the results ...
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30 views

Graphically depict statistical difference between thematic rasters

The graph shows a regression between two raster datasets with classified tree canopy cover: class 1 = 0-10%, class 2 = 10 - 20% ...class 6 = >60% (Figure 1, Figure 2). The spatial resolution for ...
4
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1answer
302 views

QGis Zonal Statistics Plugin NoData included in Calculations

I have been trying to use the QGIS zonal statistics plugin. My raster has a nodata value of -99999 and all other values are positive. After computing the mean zonal statistics there are a number of ...
3
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2answers
285 views

Performing statistical analysis of buffers?

I am doing a buffer analysis of incinerators and looking at the output areas within those buffers, is there a way of doing a statistical analysis of several buffers to see if there is a significant ...
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1answer
51 views

resampled thematic map accuracy

I've generated a map of ecoregions based on some environmental data using a semi-supervised classification where I combined a statistical clustering with random forests to generate my map. I created ...
2
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0answers
66 views

How to join two fields after calculating?

I have been working with two layers and I am trying to join them and turn them into a raster data. The first layer is a watershed layer which I have assigned each shed a location from the center point ...
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1answer
31 views

How I can sum 360 raster files in a folder with the Arcgis raster calculator?

In a folder I have 360 precipitation raster files and I want to sum them all to the raster calculator
3
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1answer
48 views

Statistical Analysis of Shapefile Proximity within Raster Image - ArcMap10.1

I have a raster image that has been reclassified into 15 equally incremented values/levels. This raster represents "sinkhole risk" in a certain county. So level 1 is the lowest risk region and level ...
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1answer
61 views

How to analyse point data as covariate for areal data

I have two data sets: a) a set of polygons with areal data variables. b) point measures of various co-variates of interest (note I do not necessarily have a point for each polygon) How do I ...
0
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0answers
27 views

Zonal statistics vs. random points?

Using ArcGIS 10.1 for Desktop, I wish to model the relation between soil productivity (SP) and a number of independent variables such as, e.g., terrain elevation and slope. For this purpose, I am ...
2
votes
1answer
35 views

Summarizing Table on 2 fields

I have a table of Census Blocks linked to ZIP4 values. I'm trying to create another table getting the unique ZIP4 values associated with each Census Block. I've tried using the Frequency, and Summary ...
14
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7answers
2k 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?
0
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1answer
28 views

How to implement a Gaussian function in field calculator?

Are there any build-in functions like Gaussian or Epanechnikov functions in field calculator? Or I have to write that by myself?
0
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1answer
25 views

Calculating GRID Statstics

I have a GRID raster dataset with no calculated statistics. I have tried building pyramids and calculating statistics with no luck. What am I missing? EDIT: For those who don't understand: 1. ...
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2answers
74 views

Lengths of lines within individual but overlapping buffers?

I have a set of points for which I have created a 12 mile buffer. Eventually, I would like to know how many kilometers of road exist within each buffer zone individually? The problem I see going ...
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1answer
121 views

Get the different values assigned to a zip code

I have a map to which I added a zip code layer and another layer which contains values assigned to every square kilometer within each zip code. I'm trying to find out how many different values there ...
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1answer
32 views

How to derive Z-score values for a given field

I have a shapefile with an attribute field with a range of numerical values. I would like to derive z-score values for this field within ArcGIS. Any tips?
0
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1answer
76 views

Counting all features in all layers of ArcGIS map to get grand total?

I have 20-50 polygon layers in an mxd and I want to find out the aggregated amount of all features (global count). The shapefiles which are the source of those layers are stored in different folders. ...
2
votes
2answers
54 views

Methods for hot spot or cluster analysis for multiple measurements at the same geographic unit?

I would like to find geographic clusters of zip codes where each zip code has a measurement of a person's age (integer), sex (categorical/binary), and if they recovered from a certain medical ...
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3answers
68 views

ArcMap Change Values Greater than Standard Deviation of Mean to Zero

I have a feature class with greater than 1000 features and I would like to change all values greater than 2 Standard Deviations to a Zero. Seems like I could possibly use Field Calculator for ...
1
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2answers
98 views

Min - Max within a zip code (statistics by area)

I'm new to ArcGIS. I have created a layer representing zip codes and overlayed it with a layer containing some data points. I want to find the min and max value of the data points in each zip code. ...
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0answers
47 views

pivot table output

In an attempt to summarise landclasses, the columns of my pivot table output are a bit mixed up with the field info regarding the three input fields that I've selected. As shown in snapshot 3 the ...
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2answers
46 views

How to track ajax WMS requests in OpenLayers interface?

I'd like to track WMS requests on my openlayers web interface. How is it possible to log on my server or in Google Analytics every WMS requests (GetMap and GetFeatureInfo would be enough)? Then I'd ...
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0answers
30 views

Applying Spatial Clustering test using R? [duplicate]

I’m very new to R so please bear with me: I have a set of area infested by a disease (AIS) annually data and I want to apply some cluster methodology to detect regions with similar (AIS) patterns. I ...
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0answers
26 views

Performing Mutiple Correspondence Analysis (MCA) using R?

I want to apply MCA (multiple correspondence analysis) to a data table containing regions as individuals, and INFESTED AREA as variable and degree infested also and the type of trees infested , and I ...
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0answers
34 views

Sextante and qgis for hotspot analysis

I want to analyze time series data for hotspot analyis. May i know whether sextante and qgis are able to generate any spatial statistics similar to Getis-O-ord in ARCGIS.Or R is required for hotspot ...
5
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2answers
2k views

Frequency, summarize tool options of ArcGIS for Desktop?

I'm looking for some general frequency, summarize tool. What I basically want is some tool like the summarize tool in ArcGIS (right click in the attribute table> summarize) that runs on all attributes ...
0
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1answer
102 views

Do I need to run regression in each samples separately?

I'd like to do smooth NDVI image by regression analysis; response of time series NDVI image to Julian date to represent the seasonal changes in NDVI as a function of Julian day. The time series NDVI ...
7
votes
3answers
495 views

How to use ZonalStats plugin?

I am using QGIS 1.8.0 on a Windows Home Premium 7 machine. I have a single band TIFF that is 187 MB in size. My vector polygon shapefile represents a regular grid of a 147x112 36kmx36km grid cells. ...
0
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1answer
160 views

How to perform GRASS v.rast.stats via QGIS

I have been using qgis for the last few months. I got interested in using GRASS tools through QGIS. I wanted to compute zonal statistics for a raster surface for a given polygon layer. I loaded the ...
2
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1answer
41 views

Overview of statistical maps/charts types

I know of a few ways to visualize statistical information on a map, like choropleth maps, prism maps or simply displaying little bar-charts or pie-charts near locations on a map. But there must be a ...
1
vote
2answers
43 views

How to add a pie chart based on all (or some) features in a layer?

I have a vector layer in a QGIS project which has about 60 items with various attributes, including a check for if an item is complete. I am trying to get a pie chart showing the percentage of the ...
3
votes
1answer
195 views

How to sum up all field values in QGIS modeler

I am building a model to generate two zones around a point, a 250m-buffer, and a ring of 250 to 1000m, where i recalculate values from an other layer according to the intersections share. The purpose ...
2
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3answers
134 views

Select layer by attribute: return top 3 records

I have a feature class in a file geodatabase using ArcGIS 10.1. I want to create a model that selects the three features with the highest values in one field (Average Price). Basically I want my ...
1
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1answer
41 views

Calculations from Feature Server and display values

Using the ESRI JS API I would like to apply some basic math based on the Shape.area of a feature and then return that calculation to the web-page. I can't see any reference to something even remotely ...
1
vote
1answer
129 views

What do “count”, “mean”, and “sum” in QgsZonalStatistics mean?

I am working with Qgis and making some analytics of lightdata. I've used these commands: rasterfile = qgis.utils.iface.mapCanvas().currentLayer().source() vectorlayer = ...
2
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1answer
129 views

How to create a x-y scatterplot from attributes in QGIS 2.0?

There are a few old packages that allow the creation of x-y scatter plots from attributes in vector data (Scattergram for 1.7) http://plugins.qgis.org/plugins/scattergrammidentify/ (SPQR for very ...
7
votes
3answers
5k views

How to calculate raster statistics for polygons?

how can I calculate sums, averages etc of raster-points (multi-band) per polygon of a vector-layer. I was told that this is called "zonal statistics". I tried that with QGIS first. There is a way to ...
0
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0answers
42 views

Why does it take so long to run zonal statistics?

QGIS 2.0 Windows 7 I have pulled agricultural data from NASS CDL in tiff format. I want to track where a certain crop has grown over the years. My intention was to use a county shapefile overlaid ...
0
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0answers
21 views

Cell Statistics in QGIS

Cell Statistics in ArcGIS will calculate the mean (or statistic of choice) among multiple rasters on a cell-by-call basis. Can QGIS do this? If so, how?
2
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0answers
70 views

Bivariate Mapping (running a single variable regression and mapping r-squared value)

I am hoping to produce a bivariate map displaying the correlation between two variables (specifically percent SNAP participation by county against several social variables). I would like to produce ...
1
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0answers
46 views

Statistically compare two density maps?

I (will) have a modelled distribution and an observed distribution of animals. If I were to interpolate these position datasets to reflect some density distribution (perhaps using a kriging ...
0
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0answers
75 views

Calculate ANOVA using GIS

It's possible to calculate a statistic like ANOVA using GIS. I'm using ArcGis, but there's any GIS software to calculate it? Thanks,
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0answers
42 views

How to export raster into ascii without losing the statistics?

I had a problem in Mike Urban with a difference between a DEM (Digital Elevation Model) and a 2D overflood model and the support group requested me to remove the difference because the problems were ...
2
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0answers
49 views

Habitat Modeling and OLS Regression [closed]

I’m performing some habitat modeling for a certain species using resource selection functions to determine optimal variables for including as model parameters. I am using OLS within ArcGIS for the ...