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14 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 ...
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0answers
13 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
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0answers
88 views

Creating multipart polygons with ArcPy? Dissolve Failure?

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 ...
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0answers
34 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% ...
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1answer
41 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
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1answer
54 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 ...
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2answers
73 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
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1answer
161 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
100 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
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2answers
129 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 ...
1
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1answer
71 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, ...
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1answer
76 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.
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0answers
25 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 ...
2
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2answers
78 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
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1answer
88 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 ...
1
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1answer
59 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
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1answer
37 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 ...
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0answers
23 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 ...
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0answers
65 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 ...
2
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1answer
41 views

Randomly distributed cases according to census data

I'd like to randomly place a point within a geographic boundary with the caveat that I would like to use census data so that points are randomly placed according to population density (i.e. more ...
1
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1answer
116 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 ...
2
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1answer
57 views

Using search and update cursors for random number generation

I am having some trouble getting a searchcursor to return a value for each record. The purpose of my code is to scan through a list of records in a field (FieldA) and based on those values populate a ...
3
votes
2answers
205 views

Step by step contour creation algorithm

I do seismic processing, and recently have been moving into doing contours. I have a question on the exact way this is done. I have watered down my problem so that I can understand from 'first ...
3
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2answers
434 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 ...
3
votes
1answer
149 views

How to create randomly points within polygons for each row of a dataframe matching a Polygon ID with R

My question is similar to this post, but because there are no "perfect" answer and above all no reproducible example I open this question. I have a "SpatialPolygonsDataFrame" and a data frame. Both ...
3
votes
1answer
298 views

Is there any random data generator supporting geometry in PostGIS?

I found few random data generators for PostgreSQL (such as this one), but none supporting PostGIS geometry type, other than point. Making points would be quite easy, but for lines with multiple nodes ...
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0answers
24 views

How do I randomly alter a raster with som correlation

I need to randomly alter an existing raster. The original raster is essentially a topography map that measures its values around a normal distribution ranging between 0.5 and 1.5 The new raster ...
7
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3answers
857 views

R - How to sampleRandom() from large raster without NA values

I have a number of vary large rasters which need to be randomly sampled with the return value being a matrix of x, y, and value. The raster package sampleRandom(raster,n, na.rm=TRUE, xy=TRUE) will do ...
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4answers
4k 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 ...
2
votes
1answer
348 views

How do I select random points within each land-cover class? [closed]

I have a MODIS file and I want to Select random points within each land cover class Extract values of rasters to the sample points. Export attribute table Could you please tell me what steps I ...
1
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3answers
782 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 ...
2
votes
1answer
292 views

Stratified Random Sampling by ID in QGIS?

I've been playing around with the Random Points tool in QGIS to realize stratified random sampling, but I'm running into a problem where I want my strata to be based on a polygon ID, not each ...
5
votes
2answers
656 views

How to perform Intersection using ModelBuilder iteration?

I would like to take the intersection of two areas (one randomly generated), and do this n times. I can do it and get one result, but I can't save all the intersection areas to a file at the end. ...
1
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3answers
2k views

Generate random location within specified distance of a given point

In a simulation (not using any GIS), I need to generate a random location that is within a specified distance of a given location. I found a very helpful post here on this exact topic: How to ...
3
votes
2answers
752 views

Script or model to create random points having multiple minimum distances within a polygon

Given: A single part polygon, total number of points to place inside that polygon, and table specifying the size of each subset (number of subsets n >= 1) of that total number of points and each ...
1
vote
0answers
370 views

Loop though records in PostGIS (using PL/PYTHON or PGSQL)

I've seen many example of loops, but I can't get that one to work. I work for a regional transit agency and each year, we conduct several surveys. I geocode everything to the house level for internal ...
0
votes
1answer
396 views

OpenLayers generate random polygon

I have a world map. I need randomly to generate polygons and render them on map. I have no problem with rendering, but can anybody suggest how to generate polygons with random geometry? (I need n ...
3
votes
1answer
447 views

Convert polygons to a number of randomly located points based on polygon size

ArcMap 10.1 on a PC. Working with a large shapefile with ~50,000 poygons with a wide range of size from 1,000+m. to <1m. I would like to convert these polygons into points so I can do some analysis ...
1
vote
1answer
276 views

Sorting points with QGIS

I have a very good idea of what I would like to do but I really do not know if it is possible with QGIS. I have points that each one corresponds to a group size and I would like to use GIS to sort ...
5
votes
1answer
2k views

Creating a subset of points shapefile with minimum distance between points in ArcGIS 10 [duplicate]

I have a sample of ~700 animal locations that I will be using for habitat selection analysis. I am trying to figure out a way to subsample my locations in a way that will maximize my sample size for ...
1
vote
1answer
126 views

Set certain amount of pixels to 1 inside of a polygon (GRASS)

I have a rather coarse vector map with polygons and want to calculate a (sufficiently) finer raster map defined by spatial extension and resolution. Every polygon of the vector map has a value ...
5
votes
1answer
1k 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 ...
9
votes
3answers
727 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 ...