# Tagged Questions

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

24 views

### How to perform statistical test for two sets of points?

(I have asked this question originally on Cross Validated; however, no good answer and someone suggested me to ask the question here). We know that we can perform statistical test (e.g., t-test) for ...
42 views

I try to find the MAX value for every distinct element in a dataset (I done this using MAX in summary statistics) but I also want to have the id of the element corresponding of that MAX in my output ...
19 views

### Calculate the frequency of classes of neighbouring raster cells

I'm struggling with a problem when working with a raster dataset of biotope types: For each cell I would like to find out the frequency of classes in the adjacent cells, e.g. from the 8 neighbouring ...
31 views

### Performing Statistics operation on field in Attribute table?

I am working with the Shapefile consisting set of points. One of its field (let's call it X) contains numeric data, ranging from 0 to 1. In order to find out the average value of field X, I opened ...
38 views

### Extracting NDVI using QGIS from multiple images to Excel?

I created 25 images in QGIS. Each image has different information about the NDVI of the area. How can I extract mean, max, and min information about the NDVI from each image and put it in Excel?
31 views

### extracting statistics from a raster within the extent of a polygon

I have a polygon representing the extent of a study area. This polygon is overlaid to a raster representing the quality of land, which is classified into 5 classes (from bad [1] to good [5]). I would ...
27 views

### How can I statistically compare the surface slope of 2 different areas?

I could use the statistical tests like t-test and ANOVA, however I am afraid those test will easily show significant differences if I use the slope values of all cells from each area.
74 views

### how to get max and min from a raster using arcpy?

I have a land surface temperature raster file and I want the max and min of it. minLSTresult = arcpy.GetRasterProperties_management(raster_result, "MINIMUM") minLST = minLSTresult.getOutput(0) ...
51 views

### Finding Median, Max and Min values from Raster Layers in QGIS

I currently have 10 years worth of January raster datasets (working on just one month at the moment) of cloud fraction cover from MODIS, and am trying to create new 3 separate rasters which will give ...
64 views

### Error Trying to Run R Summary Statistics in QGIS 2.12.1

When I try to run the R script "Summary statistics" in QGIS 2.12.1 on a Windows 7/64 bit machine, I get the error message "error in if (!file.info(DSN)\$isdir) DSN missing value where TRUE/FALSE ...
58 views

### Calculate percentages with field calculator in arcgis?

I am trying to calculate the percentage of each the area of each polygon in the selected area. I tried using ( math.fsum(!shape.area!) / !PolygonArea! )*100 and other codes but I cannot make it work. ...
23 views

### Cell Statistics failing to read rasters in list

Heyo. I'm trying to get the rasters from a list (about 32 rasters) and then sum them up with CellStatistics in arcpy. I'm using Python 2.7.8 and ArcGIS 10.3.1 I got it to work the first time around ...
158 views

### Calculating spatial correlation between features from two separate layers in QGIS

I am trying to determine whether the presence of large numbers of active duty military troops in an area is spatially correlated with higher/lower levels of violent crime. That is, are the areas ...
46 views

### Resampling gives higher MEAN when using zonal statistics

I am using ArcGIS 10.1 for Desktop. I have a value raster and a polygon feature in GCS coordinates. My raster resolution is 0.5 decimal degrees which is much larger than the size of my polygons. My ...
13 views

### Extremely high z-values for Moran's I

I made the following in advance: I aggregated population data to 100*100m Grids. Afterwards I wanted to find out, weather there is autocorrelation in the data or not. For this I applied the Moran's I ...
59 views

### Explaining different results from Ordinary Kriging and Universal Kriging?

When using either methods to create a surface from the same set of observations, these surfaces differ from each other. Visually it can be seen in the differences of the following contours ...
179 views

### Using Python to compute the distance, speed, and time between coordinates (lat/long) using haversine formula and print results within .csv

I have a .csv file with 10 columns. The first column is titled Distance_Between_Points, the second column is titled Time_Between_Points, and the third column is titled Speed_Between_Points and all ...
54 views

### How to separate out bands from hyperspectral data using R

I'm having one hyperspctral data with 426 bands, with dim 250*250*426. I want to seperate each bands. I tried like this img <- stack("name.tif") rr <- array(, dim= c(250,250,426)) for(i in ...
56 views

### Raster distance for statistical analysis

I am trying to some kind of hedonic analysis. I need to calculate driving forces for new urban areas. In order to do this, i have a raster with new urban area's and one with existing urban areas ...
52 views

### Using linear regression for geospatial data?

Say, my database has three columns. A: county (300 rows with 300 counties as index), B: X (some independent variable in continuous scale, which is the average of everyone in that county), and C: Y ...
145 views

### How to show statistically significant incident locations

First let me preface with I tried to search for this solution first but I don't really know how to word it and could not find any results so excuse me if this is a duplicate. I would like to know how ...
29 views

### Statistical bias arising out of only comparing US census block groups that have not changed (been split) over time?

Census Block Group ("CBG") study areas are notorious for changing over time. Even from 2009 to 2013, about 10-25% of the CBG's in South Carolina have not remained consistent over that time. Seeing ...
462 views

### Major bug in ArcGIS Zonal statistics?

I am using ArcGIS 10.2.2 to determine zonal statistics for a number of zones. If there is any NoData in the value raster, I want the zone results to be "NoData", precisely as advertised by the tools ...
43 views

### Raster Area within a Polygon

using ArcGIS, I have a layer of overlapping polygons and a raster grid underneath. The raster is not a continuous grid - the cells are spread out. I simply need to calculate the total area of the ...
69 views

### Index express the similarity in shape between two data sets

I have two data sets. One is points in the blue curve. The other is points in the green curve. Now I want to find a property (P) or something else like index that has the following characteristics: ...
110 views

### Invalid drop item: Calculate statistics

I have a number of rasters that I need to calculate histograms for. These are continuous rasters from 0 to 294.208 - many decimal places. I need to be able to classify the histogram down to at least ...
376 views

### How to sum pixel values of a floating point raster in ArcMap?

I have a floating point raster with values from 60 up to 95 (with decimals), it has 7077 pixels of 250x250m size. Is there a way to sum all pixel values of this raster? For example, if the raster had ...
61 views

### Where can I find geodata for the Russian терсон-мо or терсон-ате census units? Or: can osm_admin polygons be linked to those?

I'm looking to combine Russian census data with georeferenced polygons. This is for a research project looking into different aspects of mobility within the Republic of Саха (Sakha/Yakutsk), the ...
70 views

### Zonal statistics error: 0-d arrays can't be indexed

How can I fix the error 0-d arrays can't be indexed? This message appears after the tentative to use the algorithm Qgis Zonal Statistics. Detail: the algorithm worked very well several times and then ...
39 views

### How to get the upstream average of a raster data layer that falls into a river network?

I have a raster layer of a network of rivers and a raster layer of data I want to extract. For each pixel of the rivers, I need to know the upstream average of the data layer that falls into the ...
42 views

### Different results of lagsarlm in R and GeoDa spatial lag model with identical weight matrix?

I ran a spatial lag regression model in R using spdep. Due to cross-validation of my results and data-size, I ran the same model in GeoDa but the resulting indices didn't match. My data(slot): ...
146 views

### How do I Calculate Grouped Percentiles or Batch percentiles in ArcMap?

My question is similar to this one which was answered successfully: Calculating Percentiles in ArcMap? My addition is how do I batch this solution for multiple files or apply a group-by feature to ...
52 views

### Some output cells show up as noData in ArcMap Block Statistics?

I am using ArcMap 10.2.2, and I need to aggregate categorical data from 30m up to 90m and 900m resolution for species distribution modeling. The algorithms available in resample (nearest neighbor, ...
164 views

### How to calculate raster statistics for each band in qgis

i need to calculate raster statistics for RGBN (4 channels, multiband image) rasters in QGIS. In Arcgis if you use "calculate statistics" in Arcatalog, statistics are calculated for every image band. ...
52 views

### Counting points in concentric circle buffer zones of different sites in a map? [closed]

I produce concentric circles of 200 and 500 m buffer zones to see water points within each buffer zones. The buffer zones are created throughout my study area. How can I count the points found in ...
135 views

### Accessing bands in .pix (PCIDSK) file in python/arcpy

I am trying to perform zonal statistics on a single band from a multi-band raster in .pix format. I have things working great with a tiff file. I am able to access the bands using this code: desc = ...
110 views

### Zonal Statistics as Table output is missing some polygons ONLY when run from Python script

I have a raster file from which I am attempting to calculate mean values for polygons defined in a shapefile. Using the Zonal Statistics as Table tool from within ArcGIS works great. My shapefile ...
48 views

### Zonal Statistics as Table having problems with Mosaic Dataset

I have a mosaic dataset of forest cover around the globe for the year 2000 (each cell's number contains the percent of forest cover in that area). I have randomly selected a large number of points ...
170 views

### Unit of measurement from standard error prediction map

I am performing an ordinary kriging analysis and came out with the prediction standard error map. I would like to know the units of such map. Can anyone help me?
323 views

### How to calculate RMSE of geographic coordinates?

I've been working on my project and I stumble upon how I can calculate the Root Mean Square Error (RMSE) of geographic coordinates. What I have is a derived coordinates from processing LiDAR data ...
24 views

### Need statistics from US census [closed]

I am not sure if this is the right place to ask, if so please recommend a stackexchange, I am having a lot of issues getting the data approximations that I need for a report. I am looking for the ...
248 views

### Extract values from raster by using polygons

I am working with multiple raster files that cover all of united states. The file format of the rasters - GeoTIFF. I have around 100 geotiffs that I need to process. Then I have another shapefile with ...
88 views

### QGIS equivalent to MapInfo Sum Attributes for selected vector objects?

I´m looking for QGIS equivalent to the basic MapInfo tool "Sum Attributes". I´ll explain what it does: For selected objects in a vector layer, a popup window shows basic statistics such as: - Sum ...
36 views

### Can I no longer see my view counts in the new dashboard?

The inset graphic shows the relative up and down of each day's views, but I can't see any numbers. I'd love to continue tracking my monthly stats.
89 views

### Disaggregating vector layer splits

I'm fairly new to GIS, but I've got the basics down. I'm utilizing QGIS and Python to calculate election statistics by legislative and congressional districts. I'm trying to aggregate precinct level ...
60 views

### Proof low deviations in DEM compared to point dataset

I am not sure how to achieve the following consistently: I have a regular distributed point dataset (surface elevations). From this I derived several DEM using QGIS IDW Interpolation method. Now I ...
69 views

### Overlay polygons on raster in different projections

I'm overlaying polygons on a raster to get the average value inside the polygon (using SAGA->Shapes-Grid->Add grid values to shapes in the QGIS Processing Toolbox), using a geographic and a ...
91 views

### Memory issues with zonal statistics

I have got a memory issue due to the use of the zonal statistics command into a loop. It seems that after using the ZS command QGIS stores some information in the RAM (cache memory?). It is not ...