Questions tagged [sample]
The sample tag has no usage guidance.
27
questions
0
votes
1answer
12 views
Tracing back single class sample sizes of a random forest classification model (.pkl-file) [QGIS 3.16 - EnMAP Box - RFC]
A couple of weeks ago, I created some prediction models with the EnMAP Box Classification Workflow.
In some of the models I reduced the sample size for some classes as shown in the image below. Here, ...
2
votes
2answers
45 views
Randomly sampling polygons from polygon grid using the spatialEco package in R
I have a polygon grid (epsg:24381) from which I want to randomly select some polygons. Whenever I try to perform the sampling I'm getting the following error:
Error in h(simpleError(msg, call)): ...
1
vote
0answers
29 views
Appending ID column back into sampled image
With a lot of help I recently figured out how to extract NDVI values for a specific date for a collection of GPS points (Extracting NDVI value for GPS points - how can I extract NDVI value for ...
0
votes
1answer
29 views
Google Earth Engine: Sampling through image collection [closed]
I am trying to get samples from each image in an image collection and merge them into a single feature collection. So, I wrote the following code (https://code.earthengine.google.com/...
0
votes
0answers
50 views
Alternative to "Export Training Data For Deep Learning" ArcGIS's tool
My current research involves training a Mask R-CNN model with tensorflow to detect and segment buildings. I have a vector shape containing "M" features, each feature being a polygon ...
1
vote
0answers
137 views
eCognition export samples as a shapefile problem
I need sample shapefile for the other project but when I try to export it, it gives me an error like domain is empty(no images object available). How can I get the samples as shapefile?
1
vote
2answers
168 views
Combining imagery, masking and sampling in Descartes Labs Platform
I am trying to sample data from Descartes Lab imagery to train a random forest classifier in the Descartes Plaform for an agricultural region. I have already written a script to prepare the imagery of ...
-1
votes
1answer
64 views
Creating random points with "CreateRandomPoints_management()" function of ArcPy, 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 ...
2
votes
0answers
271 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 ...
2
votes
1answer
331 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 ...
2
votes
1answer
832 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 ...
1
vote
1answer
250 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 ...
1
vote
0answers
80 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 ...
3
votes
1answer
184 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
133 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 ...
1
vote
1answer
1k 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
448 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
29 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
0answers
1k 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
344 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
1answer
948 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
3answers
767 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
145 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
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?
6
votes
1answer
264 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
543 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 ...
1
vote
1answer
185 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 ...
