Geographic Information Systems

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How can I create random points with “CreateRandomPoints_management()” function, from ArcPy library, 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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29 views

Errors when sampling Large SpatialLinesDataFrame and sf road layer in R

I am trying to generate an object that contains regularly sampled points along each road in my road layer (so that there is 0.1 mile/16 meters between each point). While I can get code to do this on ...
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20 views

Are there any examples or tutorials showing Branch Version editing with ArcGIS Server JavaScript API?

I am trying to implement branch versioning in an application that I'm building using the ArcGIS Server JavaScript API. I found a blog post showing how to edit branch-versioned data in ArcGIS Pro, and ...
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1answer
65 views

Adding column in attribute table with values sampled from raster using QGIS

I am working with QGIS. I have a file with many points, and I would like to sample their values from a raster. How can I add a column in the points' attribute table and fill it with the raster ...
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1answer
282 views

Implementing proportional stratified random sample in R

I've completed a landcover classification on an Landsat Image and would like to start an accuracy assessment. I'd like a stratified random sample that has a sample number that varies based on each ...
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1answer
93 views

Sampling stratified random points using R for accuracy assessment

I want to sample stratified random points using R. I found the sampleStratified function from the R raster package. This functions samples the same amount of points for each class of my ...
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0answers
46 views

Error in sampleStratified() r

I am trying to randomly distribute points in a raster (that has 11 unique values). I followed this posting and was able to recreate it, being partially successful. As mentioned about, my raster has ...
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1answer
77 views

Sampling list of rasters in ArcPy?

I've been trying several times to sample (Sample tool from Spatial Analysis ArcGis 10.5.1) a list of rasters to a location sample (also in raster format .tif). Here's the code I've been using, and ...
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76 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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1answer
741 views

How can ee.Image.stratifiedSample() be used in Google Earth Engine to select training samples for a binary classifier?

This is a follow-on question to How can one create a binary image from a FeatureCollection in Google Earth Engine? The corresponding minimal example can be found here: https://code.earthengine.google....
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262 views

R raster - take stratified sample

This question was posted in stackexchange, where there were no views/comments/answers. I have a raster file and would like to take a stratified sample. library(raster) f = system.file("...
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24 views

Kriging with a non-uniform (not space filling with concentrated data in certain regions) sampling design?

I am using Kriging for optimization where local searches are often carried out. However, because of these local searches my sample design becomes poor and my Kriging prediction as well as variance ...
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0answers
968 views

Converting table asset data type from 'Long' to 'String'

I am attempting to generate 50 random points per land use class through Google Earth Engine. I have performed this operation before on an earlier instance, where the inputs were the following (1) ...
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277 views

Small sample size for geographically weighted regression; limitations

I am studying West Nile Virus risk factors in a specific county using mosquito surveillance data over a ten year study period. The highest resolution of the mosquito data that could be obtained was at ...
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1answer
683 views

Distance based random point selection in r?

To avoid clustering in subsequent analysis I try to randomly select points of a SpatialPointsDataFram with a given distance between the points. The remaining part should be devided for test analysis. ...
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3answers
595 views

Random sampling of many millions of Points or raster cells with ArcGIS Desktop?

I need to test the mean of two very big point shapes. One point shape has around 34.000.000 points and the other around 1.000.000. I have to do a random sample in ArcGIS 10.3.1. Unfortunately, I ...
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0answers
108 views

Random Stratified Sample in QGIS and Scale

I need to sample 7 raster layers all 30 m resolution (as some of the remotely sensed products I'm using are Landsat). I have all of my layers ready to go, but I am not sure how I can conduct a ...
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1answer
74 views

Sample values from a grid by points in RQGIS

I need to sample values from a grid by points. In RSGA, there is a function called "pick.from.saga.grid" to sample raster data set using points. Is there something similar in RQGIS?
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1answer
244 views

Why does the ArcGIS Sample tool skip rows and points?

I'm using ArcGIS 10.4 and want to export XYZ values of a raster (type: GRID) to a text file. I'm following the procedure recommended by ESRI support. However, it seems that the Sample Tool in spatial ...
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1answer
441 views

Generate sample (Gaussian distribution) and store simulations in raster stack in R

I have a raster stack, one of the raster layers is the mean prediction of a property for that pixel, the second layer is the variance of the prediction. I would like to write a function for ...
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1answer
157 views

Sample point elevation from a given contour

I need to sample the elevation at number of predefined location given in CSV format (but could convert to shapefile if needed). My input data is a shapefile of contour lines. Is it possible to sample ...