Having no specific pattern, purpose, or objective

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1
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0answers
27 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
votes
1answer
36 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
38 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
votes
1answer
37 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
74 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
votes
2answers
160 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
86 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 ...
2
votes
1answer
111 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 ...
0
votes
0answers
22 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 ...
0
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0answers
42 views

Agent Analyst - How to reduce memory use during many, many loops?

I am currently using the Agent Analyst adaptation of Repast within the ArcGIS framework. The model I've built is capable of doing what I'd like (ie. randomly generating biologically-sensible ...
7
votes
3answers
466 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 ...
4
votes
4answers
2k 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
192 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
vote
3answers
505 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
228 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
393 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
vote
3answers
1k 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
573 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
286 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
306 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
330 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
206 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
121 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 ...
2
votes
1answer
784 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 ...