Questions tagged [random]

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Selecting random set of points from existing point layer for sampling in QGIS

I have a point layer and I wish to extract a random sample of these points across the dataset based on a given attribute. For example I would like to select randomly 25 points with attribute "A&...
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  • 31
0 votes
1 answer
48 views

Exporting shapefile with random color

I have a huge shapefile with an attribute field called category. How do I add random individual colors to this category attribute and then export it with the style so that I can open it in other ...
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3 votes
2 answers
88 views

Randomly generating points using weights from raster in QGIS

I need to randomly generate 10K points throughout my region of interest, but I need to weight the point selection by a set of probability weights, stored as a raster - such that higher probability ...
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1 vote
1 answer
115 views

Creating random points only inside constraining feature class using ArcGIS Pro

Is there a way to generate random points that only fall within the area of a constraining feature class in ArcGIS Pro? I've generated random points and specified a polygon feature class as the ...
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  • 11
1 vote
1 answer
126 views

Generating random points in polygons to simulate population distribution

I have a spatialpolygondataframe that represents census tracts. I want to simulate different scenarios of population density or distribution to test a model. To do this, I want to generate random ...
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3 votes
1 answer
77 views

Creating different numbers of random points inside polygons using PyQGIS

I am developing a plugin using PyQGIS and PyQt5. I am calling qgis:randompointsinsidepolygons, where I am trying to give field input at VALUE parameter. It will take a variable number of points for ...
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0 votes
1 answer
48 views

Randomly subsetting x% of polygons where attribute value=x for a large feature class using ArcPy

Referring to this topic: Randomly subsetting % of polygons by class/attributes using ArcPy...I am trying to randomly subset a % of polygons based on an attribute that they all share. For example, I ...
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2 votes
2 answers
152 views

Generating random not overlaping circles inside polygon in QGIS

How to generate random circles with certain radius size that do not overlap, inside a polygon?
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0 votes
0 answers
78 views

Use random select based on matching values and a field value in QGIS

I have two tables one with zip codes together with addresses (tableA) and another layer with zip codes and values (tableB), this layer for example has zip code = 1234567 and a value of 50, zip code ...
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1 vote
1 answer
99 views

Creating theoretical landscape using QGIS

I would like to create a series of random theoretical landscapes (DEM) of the same size with certain parameters ranges (e.g. slope range, elevation range) and ideally with the option of defining the ...
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  • 19
3 votes
1 answer
109 views

Creating random polygons using QGIS [closed]

I have done a raster sampling analysis, wherein I extracted the raster values for a set of given points across different datasets. How do I do the same using random polygons (instead of points) in ...
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  • 143
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0 answers
25 views

Random-points-from-Classification tool (EnMAP-Box plugin) - Adding mask option by python? (QGIS 3.16, Win10)

I created random-point-vector-files from a classified rasters with a given number of points per class by the Random points from Classification tool (EnMAP-Box plugin). But, now I'd like to exclude ...
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  • 427
0 votes
1 answer
19 views

Creating random points based on a classified raster WITHOUT detour via raster-to-vector-conversion (QGIS 3.16, Win10)

I'd like to create a random-point-vector-file from a classified raster with a given number of points per class. I found several solutions or tool recommendations in diverse forums. But, all these ...
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  • 427
1 vote
1 answer
58 views

Specifying the number of points per class (not per feature) when doing stratified sampling

I am quite new to QGIS (3.16 / Win 10) and have a raster of one band with integer values from 1 to 14. I polygonized this raster in order to generate random points afterwards. The derived polgonized ...
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  • 427
3 votes
3 answers
139 views

Selecting random points from feature class

I have shapefile that includes 49 points (wells). I want to create 100 networks that include 20 randomly selected points from first network. When I used create random point tool, Some networks were ...
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0 votes
0 answers
63 views

Generating random geolocations within specific radius from given point using Golang

I am having trouble generating random geo locations from a given locations at a certain radius. I am getting an incorrect coordinate with the implementation I have done. How could I achieve the needed ...
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2 votes
1 answer
47 views

Creating random points using ArcMap

I want to create 100 random datasets in ArcMap for a particular area. Each dataset should contain 10,000 random points. I am using the "Create Random Points" tool in ArcMap. Can anyone ...
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  • 115
0 votes
1 answer
233 views

Error in poly[, 1] : incorrect number of dimensions

I'm trying to create random points using slpancs library in R. But I have this problem: random_points<- csr(poly = "zona", 1000) Error in poly[, 1] : incorrect number of dimensions
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3 votes
1 answer
184 views

How to randomly select point within grid (QGiS)

I have a series of occurrence points that I am trying to downsample to 1/20 km to avoid sampling bias. So far, I have made a grid of ~20km squares and have filtered them down to squares with more than ...
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3 votes
1 answer
225 views

Creating random Image in Google Earth Engine

The final input of my work will be quintile ee.Image objects. To test my display I would like to create an ee.Image with the value in each pixel set randomly in [1, 5] (only integer). I have already ...
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3 votes
0 answers
72 views

Randf in correlation to other field QGIS [closed]

I'm looking for solution that will allow me to create random values with correlation to other field. For example: Field_a | Field_b (that will contain random values) 1 | 0.001 2 | 0....
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1 vote
1 answer
243 views

Is it possible to read a subset of points with the PDAL C++ api?

I am using the PDAL C++ API to read LAS/LAZ data. We're finding some of the tile files are very large (160M+ points), so I wish to take a sample of them. Although the point order in the tiles is ...
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  • 1,214
-1 votes
1 answer
71 views

Creating random points with "CreateRandomPoints_management()" function of ArcPy, with minimum distance

I've been trying to create random points to sample some locations based, at first, on a field which contains the number of samples I want. But when I tried at first, in almost every feature it was ...
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1 vote
0 answers
109 views

Create random points not creating enough points-ArcMap

I'm creating random survey points within polygons based on how large each patch is, about 1 point per hectare. The points also need to be at least 175m apart. Since the plots are weird shapes, I ...
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2 votes
1 answer
115 views

QGIS Random Points in Polygon PRESERVING Attribute Table?

I have a complicated shapefile of overlapping polygons. I need to generate random points inside each polygon, which is easily accomplished using Vector -> Research Tools -> Random Points Inside ...
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1 vote
1 answer
40 views

run r.random through script in python shell

Trying to run r.random using the script but receiving an error message. It works when the module is run outside of the python shell so it must be te code, I'm new to this so I can't figure out what is ...
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0 votes
2 answers
584 views

Loop to sample random points within several polygons in R

I have a shapefile with 6 polygons, each one with a specific id. I want to create random points within these polygons, but with different sample size (each id has a specific value). The file with ...
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  • 593
3 votes
1 answer
133 views

Random points within a grid cell on a line

I'm trying to create random points on a line within a grid cell. I have a river layer within a state boundary. I have placed a grid over the state boundary. I would like to assign 5 random points ...
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4 votes
1 answer
168 views

arcpy.SelectByAttribute 'Parameters are not valid' error

I am trying to run a python script to select 5 random points in an attribute table and to loop through every 100 points to do this. When I run the function SelectRandomByCOunt within a python shell, ...
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  • 43
0 votes
0 answers
123 views

Creating random points using feature class points data within polygon using ArcGIS Desktop

I have ArcGIS Desktop 10.4. I have a shapefile containing a number of polygons with specified attributes. And a feature class containing a large number of points. both have a field in common. ...
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  • 1
1 vote
0 answers
465 views

Stratified sampling in Google Earth Engine

I am trying to get stratified random points out of GHSL (Global Human Settlement Layer) which is a classified raster over my study area (partially Europe and Asia continent), see the picture below. I ...
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  • 11
2 votes
0 answers
68 views

Getting random degrees() for PyQGIS

Performing research on a new Python script to use in QGIS where I need to create a random point based on another point. This new point will need to have its location based on a random degree (two user ...
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  • 163
8 votes
4 answers
747 views

Displacing points by random distance and direction

I have a shapefile of points representing households in a household survey. In order to conceal their exact geographic location, I would like to displace these points in a random distance (uniform ...
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  • 81
2 votes
1 answer
129 views

Selecting random points from specific attribute in yield map using QGIS

I am using QGIS. A farmer has sent me the shapefiles from his John Deere combine. They were three shapefiles that I have merged into one layer. The shapefile is from one field with a treated ...
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  • 61
1 vote
1 answer
134 views

Using Create Random points ignores number of points required in ArcPy

I am trying to generate around 117 random points over patchy forested landscape. As my forested landscape contaisn many polygons (28.000), and I would like to generate specific number of random points,...
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  • 3,226
0 votes
2 answers
114 views

Random sampling in ArcGIS Desktop

I have 14,033 points representing the location of some weather stations across the 36 states in Nigeria. I want to use an ArcGIS Desktop sampling tool to implement a random selection of 200 points ...
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1 vote
1 answer
254 views

Random selection of polygon but with certain value

i'm using QGIS, and i have a multi polygon which has more then 6000 features with population data in it, so i want to select only 400 features randomly but the selected feature need to have a certain ...
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1 vote
0 answers
614 views

Generating randomised coordinates data set using R?

I am looking to produce a data set of randomised coordinates points that can easily be generated in R with something like: Seqlat <- seq(from=-90, to=90, by=.01) Seqlong <- seq(from=-180, to=...
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0 votes
1 answer
152 views

Creating random points from attribute field

In QGIS 3.6, I wanted to create different layers of random points reading different fields of an attribute table. For example: City #cinemas #malls #stores A 15 10 12 B ...
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0 votes
1 answer
64 views

Generating random raster using weights with negative binomial distribution using R?

I'm trying to generate "species counts" in raster form -- essentially, the number of individuals in a species in a raster cell. I'd like to use the negative binomial distribution to do so. Normally I ...
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1 vote
1 answer
215 views

Error on Line 109 of Creating Random Points in Layer Bounds Tool

I am using the latest version of QGIS 3.6.3 and I am getting the same error regardless of what I do when trying to run the Create Random Points in Layer Bounds tool. Here is the error: QGIS version: ...
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  • 61
2 votes
2 answers
68 views

Update 1 random value in a group of values

I have an attribute table with a date field and a random field. The date field has three different times for each day. I need to input a '1' in the random field for one of those three times in each ...
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  • 85
1 vote
2 answers
2k views

Generating random points within series of polygons according to density using R

I have a city that is made up of a number of wards, each with an unequal population. I would like to generate a set of "random" points within the city, but the randomness is influenced by the ...
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5 votes
1 answer
1k views

Expression for random numbers without duplicates

Using only the QGIS field calculator, how to create an expression that generates random numbers without duplicates? rand (1,10) and randf (1,10) generate random numbers but could be repeated in a set ...
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  • 3,627
4 votes
2 answers
589 views

QGIS Random point inside polygon **but** - with minimum distance between points from different polygons

I am trying to generate random points in stratified area with 2 polygons. I want to generate 6 random points - 3 in each but to set minimum distance not only between points from same polygon but ...
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  • 41
0 votes
0 answers
176 views

Randomly Sample Raster Pixels With a Minimum Distance in QGIS

Is there a way I can sample random raster pixels from a satellite image with QGIS or QGIS plugin? I also need each randomly-chosen pixel to have a pre-defined minimum distance from the other raster ...
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  • 115
0 votes
1 answer
284 views

Python to generate a different number of random points for features using iteration with tool parameter values in feature attribute table

I want to generate a certain number of random points in N number of zip codes. The number of points to be generated for each individual zip code is stored the attribute of the feature class of all ...
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  • 1
0 votes
0 answers
119 views

QGIS spatial sampling tool for existing points within a polygon ensuring even spread

I would like to spatially sample 10 existing points from within a polygon. I have read the answers from "QGIS point sampling tool really slow for polygons?"; "points within a polygon" as well as "How ...
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  • 31
2 votes
2 answers
886 views

Masking random pixels in an image

I have a feature collection that is used as input for a model. In order to validate the model, I would like to mask a random percentage of pixels from each image, i.e. splitting the feature collection ...
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1 vote
1 answer
162 views

ArcGIS Random Point generator producing same points every iteration

I am generating random points to sample within a stratum. Data Management Tools > Feature Class > Generate Random Points This works just fine, except that I noticed the points I generated for ...
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  • 11