Questions tagged [statistics]
Collecting and analyzing numerical data or making numerical summaries of data.
420
questions
-1
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0
answers
21
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Assessing statistical difference in migration direction/distance [closed]
This is a theoretical question by a novice in GIS who would like to gain insight if there is an existing method in spatial analysis that will solve the problem. Performing statistical test for two ...
- 99
0
votes
1
answer
25
views
Stats approximation by rasters in QGIS
Is there a way to "switch off" statistics approximation by rasters performed by QGIS? Approximated min and max values are automatically embedded into legend labels of rasters and I would ...
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1
vote
1
answer
29
views
Percentile values of a raster file are nan
I am trying to extract some statistics from all rasters in a directory and saving them into a CSV file using Python. The script works, but the results for all percentile values are always nan. Any ...
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1
vote
2
answers
83
views
I want to test the statistical significance of the NDVI change in R
I have 20 Sentinel 2 satellite data for the period from 2017 to 2020, with 5 satellite scenes each for the months from May to September, covering one vegetation season. I am interested in whether the ...
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1
vote
1
answer
82
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I want to apply Mann-Kendall test to NDVI of Sentinel 2 data in R
I have 20 Sentinel 2 satellite scenes from 2017 to 2020 with the months from May to September to cover the growing season. I calculated the NDVI of each scene and intersected it with my area of ...
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0
votes
0
answers
28
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Same formula but different result in Google Earth Engine
Earlier, I asked Calculating statistical values from set of point values in Google Earth Engine regarding extraction of MNDWI values using sample points, which got resolved. But in that code, I am ...
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0
votes
1
answer
43
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Calculating statistical values from set of point values in Google Earth Engine
I have calculated MNDWI index. I have a set of sample points (collected over the waterbodies in Google Earth Engine platform itself) which I have used to extract the MNDWI values. Now I want to ...
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-2
votes
1
answer
45
views
Summary statistics for a set of polygons [closed]
I have a set of a few millions polygons on which I'd like to compute summary statistics.
I do know that what is relevant will depend on my needs, but I wonder if there is some agreed upon summary ...
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2
votes
2
answers
105
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Calculating the average of one field dependent on another in QGIS
I have a land use shapefile, which has a column:
labelled "LU_1", categorising different areas quite broadly (9 categories total, they are numbered 1-7, U and V).
There's also a field with ...
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1
vote
0
answers
52
views
QGIS Data Plotly widgets not installing correctly [closed]
I'm using QGIS 3.28.6 Firenze and installed the most recent version of Data Plotly. I'm trying to create a histogram with statistics of some data, and all the Data Plotly widgets don't show up when I ...
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0
votes
1
answer
23
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Spatial Interpolation of Point Layer with Count and Associated P-Value
Here's quick synopsis of the data I have. I have a dataset of just under 100 points with most points being coincident with several other points resulting in roughly 15 unique locations. Each point ...
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2
answers
62
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QGIS Report Slope Results
How could I report information about a raster result? In this case I have done slope analysis, and have reclassified it into 5 values for particular slopes. Now I am wondering if I can report ...
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1
vote
1
answer
45
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QGIS raster statistics from information panel different to Raster Layer Statistics algorithm
I am wondering why the raster layer statistics presented in the Information panel are different to those calculated using the Raster Layer Statistics Algorithm?
I note the line STATISTICS_APPROXIMATE=...
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1
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0
answers
25
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QGIS Statistic only for intersected areas
I would like to derive statistics (especially "mean") from a column of a layer, but only for those areas, that intersect with polygones of another layer.
Is there an expression that can ...
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0
answers
49
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Global surface water/ How to compare area of latest image to older images and generate histogram
Based on the Global surface water script, I would like to compare the water decreasing per year and plot a histogram for the area lost per year. I know that there is a dataset that goes by monthly ...
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0
votes
0
answers
16
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Comparing dataset with standard deviation and mean
I have a theoretical question related to the evaluation of the results I have obtained. I had coordinate of point (x,y). Now I want to check if I chose 10 sample of these data , these ten points ...
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1
vote
1
answer
58
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QGIS: Median for Raster layer zonal statistics
I want to know the median value of Raster A based on the value-defined areas of raster B. Using the Raster layer zonal statistics, I receive "only" value of sum, min, max and average.
I used ...
0
votes
1
answer
44
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Spatial statistics -- geographically weighted regression
I have some count data (electric vehicle chargers). I'm trying to model its relationship with % of cars that are electric within an area. They show linear correlation.
Normally I would use Poisson ...
1
vote
0
answers
69
views
QGIS Zonal Histogram failure on high resolution multispectral orthomosaics
I'm trying to run zonal histograms on high resolution multispectral orthos collected via drone. I'm trying do do vegetation assessments on crop, and when I run the QGIS zonal histogram function it ...
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4
votes
0
answers
104
views
Different minimum value in QGIS symbology options "singleband pseudocolor" and "Paletted/Unique values"
I want to color a TIF and manually add the max and min values to the opposite ends of a color gradient. However, different methods give me different min values for the TIF (the max is always 1).
The ...
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1
vote
0
answers
33
views
Statistical test to assess significant difference in landcover selection
I have GPS collar data that I have used extract values to points through ArcGIS Pro on MODIS landcover data. From this I have a record on the number of times the animal has been in each landcover ...
0
votes
1
answer
171
views
Download and evaluate historical OpenStreetMap data
objective: I want to download historical OSM data for Germany and check the number of new added nodes, ways, relations within a certain time range (01.01.2007 to 01.02.2007). Afterwards I want to ...
0
votes
0
answers
30
views
Statistically compare two rasters to show which best predicts the location of points, using QGIS
I have two rasters, each measuring a different environmental factor. I also have point locations of emergency 911 calls. I want to identify which raster is better at predicting the point locations, i....
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votes
1
answer
597
views
Run a for loop in R to calculate monthly mean from an Excel sheet
I want to calculate the seasonal mean from monthly long-time temperature data.
series<-data$Temperature
p=5
new=NULL
for(i in 1:length){
ydata<-series[((i-1)*p+1):(i*p)]
yavg<-mean(ydata)
...
2
votes
0
answers
103
views
How to address NA in pixel regression (local computation) with R terra package
For example, I have five NDVI TIFFs and five precipitation TIFFs. I used the code provided by Robert (https://stackoverflow.com/questions/63831287/extracting-p-values-from-lineair-regression-on-raster-...
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2
votes
1
answer
109
views
Calculate percentage of points within land cover classes QGIS
I am working on a project for my university and this is my first solo project.
I have a land cover classification with 6 classes. I also have a set of points that are recorded sightings of a mammal we ...
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2
votes
1
answer
70
views
Seeking faster alternative to arcpy.Statistics_analysis?
I'm using arcpy.Statistics_analysis to count records and it takes about 30/35min for a table with about 6.8 million records, in a bigger script, this is a big chunk of the whole time.
The result of ...
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1
vote
2
answers
243
views
How to use ArcPy SearchCursor, with a where clause, to return string formatted response with values
I am using an ArcPy Search Cursor to return the rows of a specified field within a shapefile.
The for loop iterates through the feature class and returns the value of the rows in a formatted string as ...
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2
votes
0
answers
160
views
Statistical summary of points in a polygon (QGIS)
Is there any method for calculating the average, largest value, etc. (chosen statistic value) of points within polygons and giving the calculated value to the polygon?
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0
votes
0
answers
74
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Getting percentage of parcels covered by slope polygon file using ArcGIS Pro without using Identity?
I've read the other similar stack questions and they weren't helpful, as in the processes didn't work or there was some ambiguous field references that may have contributed to my confusion and error.
...
3
votes
1
answer
136
views
Dynamic stats in the decoration title lable, by time stamp, in QGIS
I am trying to create a visualisation method of simple stats using the title label in QGIS canvas. I need to observe temporal changes in the stats, so I have tried to specify a dynamic chunk of text ...
0
votes
0
answers
116
views
Chi-square between rasters
I have two rasters (both with 10 m * 10 m resolution, for an area of approx. 1 000 km2) with the following variables. Both are categorical.
A) Habitat type with 9 different classes.
B) Soil moisture ...
1
vote
0
answers
299
views
Calculate statistics for multi bands
I would like to compute statistics for a multiband raster. How can I process?
This is my code:
python
if os.path.isfile(_tmp_path_raster):
dataset_raster = gdal.Open(_tmp_path_raster, ...
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2
votes
0
answers
90
views
QGIS starts a query "ST_SummaryStatsAgg()" on PostGIS3.0 for a raster and needs more than 10min to load
I am working on a test-server (RAID6) implementing PostgreSQL/PostGIS with vector and raster support. The aim is a big database sharing different data types including high resolution (0.5m, also 0.1m; ...
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2
votes
2
answers
369
views
Finding average value of field within selected set of points using ArcPy with ArcGIS Pro
I have a large set of points in my map and a few masks which create a grid system. I want to find the average value of one field for all the points within each grid square. I already figured out a ...
0
votes
1
answer
238
views
Do you need to factor in projection into area calculation in Google Earth Engine (GEE)?
I'm interested in calculating the area I have classified of a certain class. Do you need to account for projection to assess class area or can you run the following code and it will be accurate? I'm ...
1
vote
2
answers
612
views
Finding max value in field using ArcPy
I have a table and I want to find max and min value in specified field (f1) with their names. I used this code but I only could print max and min values in f1. How can I print their names Like the ...
1
vote
1
answer
442
views
Calculating mean of full pixels within a box in ArcMap or ArcGIS Pro?
I am trying to calculate the mean of pixels within a boundary.
I am able to find the mean using the calculate Statistics and Zonal Statistics as a table GP tool in ArcMap.
But, the issue is I would ...
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0
votes
1
answer
124
views
How to find if a non-random subsample of a raster is significantly different from the raster using ArcGIS 10.7
I am attempting to find a way to test if the values from a non-random sample of my raster values is significantly different from the raster values as a whole. In this case, I have extracted values for ...
- 113
0
votes
1
answer
135
views
adjust visualization parameters as parametric values
i want to define visualization parameters for maps as codes in main coding space not as import record
for this, i want to calculate the min and max values of image and set them in visualization ...
- 129
1
vote
1
answer
156
views
Calculate Average Vector Value Based on Points in Polygon
I initially had two layers that I "joined attributes by location." Now I have one layer.
In this layer I have several points with values from 1 - 10 and several polygons that are census ...
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1
vote
1
answer
375
views
Calculate coverage of class types in GEE
I want to define coverage of each land cover type in my study area in Turkey-Isparta.
I call ("COPERNICUS/CORINE/V20/100m/2018") dataset and restrict it for my region as below (I load ...
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0
votes
0
answers
31
views
Counting number of events from CSV file that occurred in corresponding polygon feature class using ArcMap
I'm trying to figure out how to count the number of drought events per county over the last 70 years we've had in NC and am having some difficulty. I downloaded a CSV file from a NOAA website that ...
0
votes
1
answer
55
views
Point layer data frequency within a raster layer
I need to determine which land cover has the highest/lowest number of points from a delegate point layer.
I have the land cover classified and a separate key (i.e. 1-saltwater) -- How can I find how ...
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0
votes
1
answer
2k
views
Grouping attributes based on other field using ArcGIS Pro
How do I group my attributes and show total area of districts or number of blocks for each contract?
I tried to use groupby clause in select by attribute tool but it did not work.
I work in ArcGIS Pro....
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1
vote
0
answers
96
views
Updated field is null using PyQGIS [closed]
I am going to calculate SPI values for a field in PyQGIS. I created expression for the standardized the values. Stdev and mean values getting correctly. But after update the layer, the new field is ...
- 73
0
votes
0
answers
30
views
Finding mean and stdDev of vector layer field using PyQGIS [duplicate]
I am going to standardized a vector layer field in Python console in QGIS, for that I want to get mean value and stdev value of the field.
How do I find mean and stdev in using PyQGIS.
I tried this. ...
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0
votes
0
answers
106
views
Finding average value from polygon areas in fishnet cell based on lat/long of points using ArcGIS Pro
I have created a fishnet of
0.5x0.5degrees and wanted to know the average lat/long in each cell in ArcGIS Pro.
How could I accomplish that?
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0
votes
0
answers
98
views
QGIS LecoS edge length
I am using the LecoS plugin to analyze areas I have previously mapped. The problem is, that these maps are square, which means, that the areas inside are cut. e.g. the forest continues but I have only ...
0
votes
3
answers
131
views
GRASS - Calculate 90th percentile of a timeseries dataset
How can I calculate the 90th percentile from a registered timeseries dataset of 30 rasters in GRASS?
GRASS timeseries has 2 "statistical" commands which are t.info and t.rast.univar. ...
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