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Questions tagged [sample]

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3
votes
0answers
33 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 ...
0
votes
0answers
42 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 ...
0
votes
1answer
452 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. ...
0
votes
1answer
197 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....
1
vote
0answers
88 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("...
1
vote
0answers
16 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 ...
1
vote
1answer
113 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 ...
1
vote
0answers
592 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) ...
1
vote
0answers
205 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 ...
0
votes
3answers
424 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 ...
1
vote
0answers
93 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 ...
1
vote
1answer
73 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?
6
votes
1answer
235 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 ...
2
votes
1answer
316 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 ...