Questions tagged [statistics]

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

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21 views

Calculation of RMS between two grids [duplicate]

I want to calculate the RMSE of two grids based on their z-value: a calculated and a reference grid. I do have the statistics: Cells, Range, Min, Max, Sum, Mean, Variance, St.dev. How could I solve ...
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0answers
217 views

Statistically comparing positions from two track datasets? [closed]

I have two datasets with positions that I need to compare. One would be the "observed" positions (someone took the GPS positions manually) and the other one was calculated using a software. To use ...
6
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1answer
705 views

Why covariance values are different in R and ArcGIS?

I've calculated covariance between 7 rasters using R and ArcGIS. It gives me different results. Each times covariance values from R are approximately 1.874 times higher than ArcGIS values. R - ...
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1answer
516 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
1k 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 out-of-the-...
6
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2answers
13k 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 ...
7
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1answer
436 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
486 views

Extracting LiDAR metrics with TerraScan?

I want to extract from a las file statistics such as height percentiles (percentile 95, for example) among others. I can do it with Fusion (using Cloudmetrics and Gridmetrics tools), but I would like ...
2
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2answers
805 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
150 views

Statistical Analysis of Shapefile Proximity within Raster Image using ArcMap?

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 ...
2
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1answer
1k 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 ...
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1answer
127 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?
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1answer
72 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
1k 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 ...
3
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1answer
3k views

Deriving Z-score values for given field using ArcGIS for Desktop?

I have a shapefile with an attribute field with a range of numerical values. How do I derive z-score values for this field using ArcGIS for Desktop?
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1answer
1k 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. ...
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3answers
492 views

Changing Values Greater than Standard Deviation of Mean to Zero using ArcMap?

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 ...
4
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2answers
1k 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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1answer
790 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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2answers
214 views

Determining Min - Max within zip code (statistics by area)?

I'm new to ArcGIS Desktop. 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 ...
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0answers
1k views

Using pivot table output? [closed]

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 ...
0
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2answers
422 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 ...
1
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1answer
825 views

Running regression in each sample separately? [closed]

I'd like to smooth an 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 ...
1
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1answer
176 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 ...
3
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1answer
515 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
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3answers
408 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 ...
1
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1answer
328 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 ...
5
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1answer
2k 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 ...
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1answer
1k 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 = qgis.utils.iface.mapCanvas()....
3
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3answers
1k 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 ...
2
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0answers
386 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 ...
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0answers
293 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 ...
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0answers
253 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
189 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 ...
2
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1answer
610 views

Combining and displaying demographic data?

I am currently undertaking a demographic research project for my employer. We have the data on income, age, sex, language, transport etc and I have mapped most of it and created some thematics of said ...
1
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1answer
272 views

Creating quintiles in QGIS when the number of observations per row is variable

I have a list of 100s of schools (1 per row), and a variable column with the total students in each school. The number of total students in each school varies widely. I want to split the list of ...
1
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2answers
126 views

How do simple statistics based on polygons?

I have a shapefile from a city. I divided this shapefile into polygons (squares, majority). I would like to perform simple statistics in each square in a easy way, because it is almost impossible to ...
0
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1answer
94 views

How to use the local macro to do ZonalStatisticsAsTable in batch

I have a series of files named as 'rawfile200101', 'rawfiles200102',...,'rawfile201104'. I want to do ZonalStatisticsAsTable for each of them with names corresponding to the time of the raw files, ...
0
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1answer
125 views

How to calculate statistics for several sub-catchments (polygons) in the same time? [duplicate]

I have a shapefile of groundwater management zone which is composed of 40 sub-catchments (40 polygons). I'd like to calculate the max., min. and mean elevation for each sub-catchment. Would you please ...
0
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1answer
249 views

How do I get basic statistics on a field in a joined table?

I have a shapefile to which I've joined a table, matching with an ID field. All the fields of the table show up correctly when I open the shapefile's attribute table. But when I go into vector/...
1
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1answer
47 views

How to Compress/Stack Landscape features to examine spatial distribution and fragmentation?

I was wondering if anyone could help me figure out how to compress landscape information from multiple rasters (or polygons) into a single output. Basically, I want to explore how landscape ...
4
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3answers
7k views

Iterate through multiple Raster files and compute statistics using Zonal Statistics

I have a large number of raster images. What I'd like to do is to compute statistics on different sections of these raster files using a polygon. I think everyone is suggesting Zonal statistics. ...
1
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0answers
247 views

Mann-Whitney U test for rasters

I'm doing a Mann-Whitney U test to compare two very large samples (sample size 1 = 13250; samlple size 2 = 38871) originating from a shapefile with 52121 features. I know t-tests are not recommended ...
2
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1answer
148 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 ...
3
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0answers
40 views

Finding closest anticorrelated polygon or automate what is learned in semivariogram?

I am trying to do spatial autocorrelation of sorts based on a layer of polygons of mean rainfall data. I want to see how rainfall deviates from a certain point on the landscape. Essentially, I want to ...
2
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1answer
4k views

How to call processing toolbox in Qgis' python console

I have been trying to use processing toolbox via python console in Qgis 2.0.1. I am able to write the following comamnds: I am particularly interested to run 'r.statistics' from GRASS module. My ...
4
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1answer
2k views

PCA on correlation matrix in ArcGIS

I am trying to run a PCA on a set of normalized raster bands within ArcGIS. I would like to calculate the PCA on the correlation, not the covariance, matrix of the PCA, but Arc as far as I can tell ...
0
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1answer
1k 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 ...
3
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1answer
520 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 ...
5
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2answers
337 views

Different models, different contours: are they comparable?

I will get contour lines of electromagnetic field strength around power lines. The contours will be calculated by different agencies using different models. We need to check whether the resulting ...