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0
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0answers
15 views

Does the random number generator used by v.random return duplicates?

Using v.random, r.random, etc., can the same sight/location be selected? Meaning, can a location show up more than once?
4
votes
1answer
47 views

How to create random points in overlapping polygons?

I have a shapefile with ~1840 polygons, many of which overlap. I'm trying to find a way to create 1000 random points per polygon, based on polygon ID. I don't see a way to this using the GUI Random ...
3
votes
1answer
44 views

How to generate random points that lie on a line in qgis?

I have a shapefile with track lines and I need to generate random points from each 1 km of every line. There is a function in QGIS Random points but it offers to generate random points only inside a ...
1
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0answers
36 views

Creating random points using density-QGIS

I'm trying to generate random points at a specific density within a polygon layer. The polygon layer has 1850 features and I'm looking to have random points within each feature at 1/meter. Going ...
-1
votes
2answers
59 views

Generate random floating value

I need to generate random floating numbers between 0 and 1 in the field of attribute table for ArcGIS 10.3 version.
3
votes
2answers
971 views

Using arcgis.rand() with variables from code block of Calculate Value tool?

Within a larger ArcGIS ModelBuilder model I am trying to populate a field in an attribute table with a random number, using Calculate Value. The overall distribution of random numbers needs to follow ...
1
vote
0answers
190 views

Creating multipart polygons with ArcPy Dissolve? [closed]

I need the functionality of the editor > merge command for use in a python script tool. I realize this function is not directly accessible through ArcPy, but I am hoping someone can help with a work ...
1
vote
1answer
34 views

Random Selection using Select By Attributes tool in ArcMap?

How I can make a SQL syntax to generate "RANDOM SELECTION" in Select by attributes tool in ArcMap?. E.g. We have two kind of sample: Quantitative an Qualitative data. Quantitative (seven cases): 1,...
5
votes
1answer
74 views

Stratified Random Sampling Tool

Is there a way to produce a certain amount of random points over different classes in a raster in QGIS? I have extensions such as GRASS or GDAL, ...
0
votes
0answers
24 views

random stacking order of point symbols

I have >1m point symbols across California, divided among ten "orgs." At the scale of my map, all are coincident with others so that the org layer at the top of the TOC dominates. I would like to ...
1
vote
3answers
44 views

ArcMap Random Points Minimum Distance Field not able to use units

I would like to create random points with a minimum distance based on an attribute field (polygons with a larger area need random points with more space between them). In theory this can be done. ...
5
votes
2answers
90 views

Placing random line segments within polygon?

I would like to generate multiple line segments of a fixed length, a random bearing, and both segment endpoints within the polygon. It's not clear from the example, but it's fine if the segments ...
3
votes
0answers
34 views

Sample Design for Kriging [on hold]

I am taking soil samples on an agricultural plot and will be using the results as input to create a semivariogram for kriging in ArcGIS. This plot features raised planting beds in which the test crop ...
4
votes
1answer
78 views

How to randomly position coordinates within a containing feature in QGIS?

I have geocoded address data, and I am wishing to randomly position it within the census tracts that they are in to obfuscate... So the points are still within the feature but randomly move around so ...
2
votes
0answers
25 views

How to generate random points from classified raster layer?

I need to generate random points using a raster layer, which is classified into 5 classes of TPI (terrain position index). This should be a stratified random sampling design, with an equal amount of ...
0
votes
1answer
22 views

Add a random value of the order of 10^-2 to raster layer?

I was doing some raster analysis for smoothing in ArcGIS, one of my task is adding a random value of the order of 10^-2 to a raster layer. Does anybody know how to do it?
0
votes
1answer
26 views

Adjusting ArcMap Model to Create 1000 Iterations of Random Data Files with Spatial Join?

I have created a model that creates a random point data set for a certain area, conducts a spatial join of these points to polygons, calculates the frequency of a certain field in the joined table, ...
4
votes
1answer
100 views

How to insert random points with weight?

I have a polygon shp divided in 5 regions. I want to fill it with 1000 random points but not to be so random :). I want 300 points to fill one region 100 another...for the moment the one tough ...
2
votes
4answers
1k views

How to create random point in according polygon for each dataset entry in a list (with R)

I have an area divided into polygons, and a dataset of observations which has a common field with the polygon layer. I now would like to generate a random point for each dataset entry within the ...
1
vote
0answers
78 views

Random forest in ecognition

I'm using eCognition to mapping roof materials from SPOT 6 image. I have used nearest neighbour classification but the result is not so good. I'm trying to apply a random forest classifier if it is ...
3
votes
2answers
65 views

Knowing if there is correlation between roads and observations in ArcMap?

I am using ArcMap 10.3.1. I am trying to find out whether some observations have been made randomly throughout a landscape, or they are biased towards the location of roads and paths. I have a ...
3
votes
1answer
53 views

creating unique sets randomly distributed values for many defined areas…in a raster.

I have a large approximately circular study area comprised of 5000+ polygons which represent forest parcels. For each of these polygons I have up to 4 different species. These species occur in ...
2
votes
2answers
120 views

How to select 200 random points within a 100m radius in Postgis

I'm currently learning to use PostgreSQL and PostGIS. I would like to know how to write the SQL that would allow me to select 200 random points within a radius of 500m from a user defined centre point....
5
votes
2answers
131 views

How to randomly select n points within a radius in QGIS?

I have a dataset of 5000 records which I've plotted over an OSM layer using QGIS and I wish to randomly select 50 from within a radius of 2km from a point of my choosing. It is similar I think to ...
1
vote
2answers
265 views

Random Value Generator

I have a python code where I am trying to assign a unique, random value to every row. I have tried: maxvalue = int(arcpy.GetCount_management(shape).getOutput(0)) + 10000 for row in arcpy.SearchCursor(...
10
votes
5answers
7k views

How to randomly subset X% of selected points?

What methods are available in ArcGIS 10.2 to randomly subset a selection of points. For example, in the attached screenshot I am interested in keeping 20% of the selected points and deleting the rest....
2
votes
2answers
221 views

Creating random points using QGIS using Random points tool?

I have a polygon layer that has plot layouts of an area. I want to create a random point on each polygon. I tried to use the Random points tool (Vector->Research Tool->Random Points) to create the ...
0
votes
1answer
38 views

Creating random points within polygon from database?

Although i have a solution for it in ArcGIS named hawth's tool but i wanted to know whether it is possible in QGIS or not, additionally i am not having lower version of ArcGIS on which i can do my ...
4
votes
2answers
730 views

Randomly sampling points in R with minimum distance constraint

I'm trying to randomly select a number of points within my data frame (example data below) with a constraint that the minimum distance between the selected point must be greater than a certain ...
2
votes
1answer
127 views

What is CID field created by Create Random points?

In ArcGIS the result of Create Random Points tool when using a feature class to constrain the extents has an attribute called CID. What do the values in this field represent?
3
votes
1answer
194 views

Is the QGIS “Random selection within subset” selecting spatially random or randomly from the attribute table?

I am trying to figure out exactly what is being randomly selected. I have a layer of road segments and I would like it to select a road segment at random within a neighborhood (the subset). This would ...
0
votes
0answers
19 views

How to access point maker

I have been trying to create random points on ArcGIS, my problem is I want them to be circular and have uniform distance between them, was reading somewhere and found out there is a script called ...
0
votes
0answers
18 views

How to randomly apply a feature from the attributes table (an area) to a bigger area in ArcGIS 10?

I am rather a beginner at ArcGIS and I have absolutely no idea how to do this. I have to design an agricultural area, which I have the whole of it, but I am not sure which farm plant which crop and so ...
1
vote
0answers
69 views

Creating random points using QGIS?

Has anyone else had any issues using the random points tool in QGIS? When I try using it I'm selecting the option to use a value input field. The tool starts but then freezes once it gets to the 10% ...
1
vote
0answers
35 views

Random points by percent coverage

Yes, I know the math behind this is simple, but I'm looking for a way to automate the process. In ArcGIS 10.2.2. is it possible with the Create Random Points data management tool to generate a set of ...
1
vote
2answers
227 views

How to generate random points from FIDs using ArcPy or ArcGIS Field Calculator?

I'm trying to generate a shapefile of random points using FID from the attribute table. My attribute table has 800,000 features and I only need a sample of 240. Is there a way to do it in arcpy or in ...
2
votes
1answer
267 views

Using Python to select random location from shapefile?

I have multiple shapefiles with bars names and location attributes and I want to create a script which asks the user for the area or shapefile name where they want to go and then prints a random ...
2
votes
1answer
628 views

Create random points in ArcGIS on a polyline in a polygon

I am trying to create 100 random points, 1 within 500m of 100 points I already have. I have created a buffer and can easily create 1 random point in each, but now I want those points to lie on a ...
4
votes
2answers
278 views

How to randomly move points?

I have a feature class with a large amount of points. My purpose is to randomly move these points to see what happens as a result. Are there specific tools or Python programming methods to accomplish ...
10
votes
3answers
881 views

How to create random points outside polygons?

The tool Create Random Point is able to generate a certain number of points within polygons. I am wondering, given a bounding box, is there any way that I can generate random points outside those ...
1
vote
1answer
101 views

creating a random gdal raster with random predefined values

So far I have developed the below code but for some reason it only works for say one class of landuse instead of two. Would you please tell me where I have gone wrong? Thanks so much import os, numpy,...
0
votes
1answer
250 views

creating a random raster image using gdal

I want to create a random image containing say three classes with predefind percentages of each of the classes using gdal in python.Any sample code would be very appreciated.
2
votes
2answers
307 views

Creating Random Points that respect minimal distance across features / strata using ArcGIS for Desktop?

I have a shapefile with multiple polygons in which I want to distribute random points. Each polygon should contain exactly one point. The minimal distance between the random points should be 200m. ...
1
vote
1answer
115 views

Python Code for generating random points not working!

I am trying to create some code to generate 10 random points within a vector layer's districts: layer=iface.activeLayer() import ogr import sys import random from shapely import wkb, geometry Moz_no=...
1
vote
1answer
93 views

How to create landscape resistance map using path level spatial randomisation in QGIS?

I need to create a landscape resistance map based on path level spatial randomisation, as I have read in some research papers. Are there tools for this? I need to randomly shift and rotate the the ...
0
votes
1answer
80 views

selecting a random sample of parcels

I am faced with the following issue. I got a raster map showing the position and extent of land parcels within a 35 sq Km area. The number of parcels is about 200. In anticipation of the following ...
0
votes
0answers
28 views

How to use random number generator to select by attributes in ArcMap? [duplicate]

I am not familiar in using Python and random number generator. I was wondering how to select 250 rows/values from a column named "JUROL". Every value in that column is different and the column 5,000,...
1
vote
0answers
102 views

Generate random points for IDs with similar coordinates with ArcMap

I have a dataset which consists of IDs with addresses and coordinates (long/lat). Some of the IDs have similar coordinates. How do I generate random points for the IDs that have those similar ...
5
votes
1answer
2k views

Is there a source for free CSV files with geo data and other desired fields? [closed]

I'm writing some software components that process geospatial data. The input data is a CSV with general columns (e.g. name) and geo columns (e.g. city, lat or zip). I would like to test these ...
1
vote
1answer
236 views

arcpy geometry difference method fails randomly, not reproducible

Has anyone used the arcpy geometry difference operator and seen unexplained errors like what I describe below? This is a weird one. I have a script that calculates wave fetch distance in the ocean ...