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

learn more… | top users | synonyms

2
votes
1answer
195 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 ...
1
vote
0answers
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 ...
9
votes
5answers
10k 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 ...
1
vote
1answer
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. ...
0
votes
2answers
42 views

More information from Summary statistics tool in ArcGIS

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 ...
1
vote
1answer
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 ...
2
votes
1answer
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 ...
6
votes
1answer
2k views

ArcGIS median value from layer?

I've been hunting around ArcGIS 9.3 and having no success at finding a tool/function that can give me the median (not the mean/avg) tabular value of a spatial database. For example, if I have a data ...
2
votes
1answer
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?
1
vote
1answer
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 ...
4
votes
3answers
3k views

How to count occurrences of one field grouped by values of another?

Is there a way of calculating the number of unique text strings in a field in ArcGIS 10.1? I have a number of repeated strings in this field, but would like to calculate the number of unique strings ...
1
vote
1answer
625 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?
2
votes
0answers
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.
4
votes
2answers
75 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) ...
1
vote
2answers
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 ...
5
votes
1answer
4k views

Recording frequency of names in the attribute table?

I have a question with ArcGIS 9.2. In an attribute table the column [name] includes the name of every place in this layer. Next to that (in columns [numbers]) there should be recorded how often a ...
4
votes
1answer
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 ...
0
votes
1answer
59 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. ...
0
votes
1answer
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 ...
2
votes
1answer
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 ...
9
votes
1answer
159 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 ...
8
votes
3answers
261 views

spatial and spatiotemporal analyses

I have a dataset that consists of 247 mosquito traps placed in fixed positions and sampled weekly for 23 weeks. I also have dengue disease incidence data (indexed to home address) during the same time ...
0
votes
0answers
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 ...
1
vote
0answers
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 ...
12
votes
4answers
589 views

How is margin of error reported on a map?

When reporting estimates you should always include the margin of error. There are conventional ways of reporting margin of error in a table, text or graph. But, how do you report margin of error for ...
2
votes
3answers
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 ...
11
votes
2answers
3k views

How to calculate average slope in a grid?

This is actually a two part question: Which methods are there to calculate average slope by unit (say km²) for a given area? Are there any special requirements on the data - like additional ...
1
vote
2answers
75 views

Summarizing values in column?

In my vector field I would like to summarize all values in a column, how yo do so? If I right-click in the attribute table it is possible to choose summarize, but if I do so and select the column I ...
1
vote
0answers
566 views

QGis Grid statistics for polygons error - Module caused access violation!

I'm trying to calculate statistics for a raster layer using an overlaying polygon layer, I'm using SAGA "Grid Statistics for polygons" function, but it returns an error, sadly.. So in the sextante log ...
6
votes
2answers
3k 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
votes
0answers
35 views

Different hierarchical clustering results [closed]

I'm running a hierarchical clustering on a sample of data using the steps below: library(RODBC) setwd('D:/r/cluster2') channel <- odbcConnectExcel('cluster.xls') data <- sqlFetch(channel, ...
3
votes
0answers
145 views

How do I statistically compare positions from two track datasets?

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
votes
1answer
989 views

Explaining different Standard Deviation results from same data in ArcGIS Desktop and MS Excel?

I have done some interpolation in Geostatistical Analyst in ArcGIS and I got the Standard Deviation (SD) a bit different from the SD that I calculated in Excel Spreadsheet. What algorithm does each ...
2
votes
2answers
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, ...
1
vote
0answers
181 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 ...
12
votes
5answers
2k views

Determining min and max values in an ASCII raster dataset using Python?

I have a raster dataset in ASCII format. Using Python, I need to determine the min and max values inside the dataset. I've been told that the header information is key, which contains things like ...
1
vote
1answer
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 ...
1
vote
0answers
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 ...
1
vote
0answers
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 ...
0
votes
2answers
575 views

Using Add Field, Calculate Field within ModelBuilder? [closed]

I have two questions regarding ModelBuilder. I have a point layer with Crop Yield values. I need to Add Field called "Count", then do a Calculate Field, Count = 1. The problem that I'm running into ...
2
votes
2answers
377 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 ...
16
votes
3answers
463 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 ...
1
vote
0answers
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 ...
4
votes
1answer
4k views

Detecting duplicate attribute values in table using ArcPy without Advanced/ArcInfo level license?

In ArcMap, the right-click Summarize option very quickly creates a frequency listing of the chosen field: Note that the count field shows the count of duplicate values. How can I access this ...
4
votes
1answer
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: ...
1
vote
0answers
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 ...
2
votes
1answer
181 views

Retrieving proportion of pixels in R

I'm trying to retrieve the following pixel statistics: Proportion of zero value pixels: [nº of zero value pixels / (total nº of pixels - nº of NA pixels)] Proportion of pixels smaller than 3rd ...
1
vote
0answers
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 ...
0
votes
0answers
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): ...
0
votes
1answer
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 ...