Questions tagged [image-classification]

Image classification refers to the task of extracting information classes from a multiband raster image.

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Classify the image by a field in its attribute table using QGIS software

I created the attribute table of raster data in ArcMap software. There is a field that I added in the attribute table that I created. I can reclassify the image using the field I added to the image's ...
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Issue in applying condition expression to all band values in Google Earth engine

I want to apply the following condition statement to all the pixels of an indices image having only 1 band. The condition is as follows- For that first I have calculated the mean value of my image. ...
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Is there a way to obtain the variable importance for a specific class in Earth Engine?

I used a .smileRandomForest() and I know that by calling .explain() you can see the relative importance of the variables for the general classification... but I would like to know which inputs ...
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Using values of a groups of objects to create an image in GEE

I have calculated the 90th percentile for each class of land cover using the reducer ee.Reducer.percentile([90]).group The result is a group of objects and I don’t know how to use it. I would like to ...
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Supervised classification desn't work as expected in ArcGIS Pro

When applying supervised classification in ArcGIS Pro 2.8.4 the whole image becomes as one class as shown in the video below: https://youtu.be/8C0XoNU3hZY Does anyone know why this issue occur?
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R RStoolbox not picking up a SpatialPolygonDataFrame as a Polygon

I am trying to perform a supervised classification via RStoolbox. I am using a SpatialPolygonDataFrame as the training data. Now, even though rgdal picks up the polygon, RStoolbox returns an error. ...
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Vegetation Identification Plugin for QGIS

I was wondering if anyone knows of a deep learning plug in for QGIS that can identify different species of vegetation using high resolution RGB or multi-spectral imagery. Unfortunately I have not been ...
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Calculate transition of different NDVI classes from pre and post NDVI in Google Earth Engine

My competency in GEE is quite low. I have calculated 2 NDVI layers (pre and post-disturbance NDVI). I have separated these NDVI layers into 4 classes according to NDVI values. Now I need to calculate ...
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Google Earth Engine: summary statistics of an image by another image classified

I want to summarize the value from one image by the label provided by another classified image which only with two labels. But the reduceRegions function needs the FeatureCollection to provide the ...
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Fatal error using orfeo toolbox (otb 8.0.0) algorithm Computeconfusionmatrix in QGIS 3.22

I tried to compute a confusion matrix of a raster classification with otb's Computeconfusionmatrix using vector data (polygons) as reference input. When I run the same algorithm in mapla (otb ...
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Train Image Classifier (orfea): Could not load selected layer/table

When attempting to input vector data into the Orfea TrainImageClassifier, it shows the error: Could not load selected layer/table. Dependent field could not be populated. This occurs when I attempt to ...
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How to classify tree cover overlapping roofs in eCognition

This might be a fairly simple question, but I'm new to eCognition. I'm using Developer 10.2. For canopy that overlaps rooftops, I need to define these areas as separate objects and classify as canopy. ...
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How to increase accuracy of object based image classification result in QGIS Orfeo toolbox?

I am working on the subset of a Sentinel 2 image to identify solar panels from the satellite imagery. So I used the OTB plugin in QGIS Desktop 3.20.3 for segmentation and object based classification. ...
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Difference between two Google Earth Engine functions

Do you know what is the difference between ee.Clusterer.wekaKMeans and ee.Clusterer.wekaCascadeKMeans?
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Image Classification

I have created classes in my image classification but I am unable to create a signature file, please help. The attached image describes how it appears. I wanted to know why my laptop is unable to ...
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Maximum Likelihood Classification with No Output using ArcMap

I'm working on a project in ArcMap 10.7.1 and I'm having trouble with the Maximum Likelihood Classification function. I created four classes in my training sample manager (25 samples for 3 of the ...
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Training Sample Manager Icon is not showing in Image Classification Toolbar

I have experienced during working that Training Sample Manager Tool was not showing in the Image Classification wizard toolbar.I have attached a picture here. please help me because, without Training ...
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Supervised classification using spectral signature without using any indices like NDVI for crop classification of two classes only

Code: var S2filtered = S2_2A.filterDate('2021-04-1', '2021-04-16') .filterBounds(roi) .sort('CLOUDY_PIXEL_PERCENTAGE') .first(); var S2clipped =...
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Exporting a classified image in GEE without getting a BLACK raster image

I have been trying to export this classified image. I want my GeoTIFF file to show this view... But every time I export, my image turns out Black. after some digging i got to learn that I need to ...
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How to extract number of pixels of a polygon in GEE script?

Im working on a time serie for both S1 and S2 in GEE. I created training data for 72 images. For each image I created 2 FeatureCollection, 5 polygons for water and 5 polygons for no water. The ...
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Manual classification combining bands and defining values in GEE

I would like to perform some manual classification on a single image of S1-data which is fairly simple: either a pixel is classified as 'Water', or it is classified as 'Land'. I did these ...
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ArcGIS Pro 2.8 SVM Kernels

What SVM (Support Vector Machine) kernel does ArcGIS Pro use?
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Creating chart to evaluate training samples for image classification in ArcGIS Pro

I am running ArcGIS Pro 2.9.0 I’m trying to evaluate the training samples I made in the Training Sample Manager. As far as I can tell this is not available directly from the manager. I saw some ...
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Raster pixel size changed after classification QGIS

I've been trying to classify an imagery with k-means clustering for grids tool in QGIS 2.18.22. The imagery is acquired from Sentinel 2-B which should have 10m sized pixel. Before classification, i ...
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126 views

Supervised Classification: determining Training & Validation Data Sample Sizes [closed]

How does one determine Training & Validation sample sizes for Supervised Classification? My scenario: I'm using a previous year's classified map (2019) as an "a-priori" guide for picking ...
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Landsat 7 gap filling in Google Earth Engine [duplicate]

I want to remove gap in Landsat 7 images. I don't know what changes should I do in order to remove these gaps. My code to download image collections: //load landsat 7 image collection var ...
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Choosing projection for mapping urban sprawl in Dubai

I am doing an urban sprawl classification on Dubai with imagery from Landsat 8 and Landsat 5, in 2015 and 2000 respectively. I was wondering if anyone had a suggestion on the best projection for this ...
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3 votes
2 answers
123 views

Extracting polygons from scanned GeoRef images based on colours in QGIS

I would like to extract a polygon based on it's colour from a scanned map georeferenced in QGIS. In the image, I would like to extract all of the blue as a separate shapefile/GeoPackage instead of ...
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114 views

Calculating area of single class in Google Earth Engine

I'm doing a research about evaluation of the effect of catastrophic forest fires in Yakutia in 2021. I did some classification of three different classes: 'burned_area', 'vegetation' and 'water'. Here'...
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1 answer
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Creating images by calculating other images

I have some categorical images (Y, T, Max, Min, MaxUp, MaxLo). Each image has integer values in different ranges. I want to create an image MinUp that MinUp = T when Max = MaxUp ...
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Export Training Data for Deep Learning with additional metadata

I am using the Export Training Data for Deep Learning tool using the Labeled Tiles option to export one image per polygon with a class annotation. However, I would like to have the Long Lat of each ...
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Reclassifying raster after image classification in ArcGIS Pro

In the ArcGIS Pro Imagery tab, there is the possibility to reclassify an image after classification to manually change misclassified pixels to their correct values, however, after doing this, my pixel ...
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Mode Spatial Filter

I want to run a Mode filter (for example: 3*3 pixel) on the classification result in Google Earth Engine. But I can not find the command of this filter.
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Identify Pavement Markings from Satellite Imagery and export to shapefile

I have a 10cm x 10cm aerial photo of a city which I plan to use for classification of pavement markings (e.g lane arrows, lane lines, bike stencils etc.). Currently, the process I'm envisioning to ...
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Copy Raster results in darker satellite image

I am using the copy raster tool from the raster dataset on two Sentinel 2A satellite images so that I can remove the black excess background detail in order to mosaic them together without the black ...
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View values of clusters after unsupervised classification by NDVI in Google Earth Engine

I am creating unsupervised classifications of an area to detect landscape/vegetation change over time. For each year: I have created an NDVI of the area based on a composite of Landsat images ...
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Separating (grouping) different crop types that are phenologically the same

I have a bean farm plants UAV images, but they are different crop types, and others that are phenological the same. Can I cluster the plant fields using the UAV images? I cannot figure out from the ...
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1 answer
296 views

Merging masked image collections in Google Earth Engine [closed]

I am trying to merge two masked grassland classes extracted from the 2019 Copernicus global landcover 100m data product. I called grass1 and grass2 as separate variables and then used the var ...
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Accuracy assessment in GEE with an external data source

I'm new on GEE and I'm trying to perform an accuracy assessment of a supervised classification from S1 of a flood area, by the use of a confusion matrix. Once the model is created, in order to ...
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2 votes
1 answer
141 views

Spectral angle mapping from reference spectra in QGIS

I am trying to classify an ASTER image based on VNIR and SWIR reflectance of various rock types. I have standard reflection data for each rock type from the USGS spectral library and want to preform a ...
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Planet SkySat - Differences between image strips

I'm trying to understand why i'm seeing variations in the analytic (surface reflectance) imagery brightness values in Planet SkySat imagery between image strips that were collected around the same ...
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How to add values of a mask image as one of the classification classes

I have performed supervised classification on GEE in the Russian Lena Delta to map different vegetation classes using sentinel 2 images (BUT i had to mask out the water and sandbank pixels) to improve ...
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1 vote
1 answer
662 views

Image Segmentation and Classification with Google Earth Engine

I'm new to using Google Earth Engine and I obtained the following code from Medium and tried to update it with the AOI and training data for my specific area. I am trying to classify landcover for an ...
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QGIS: Error [24]: The following signature does not match the band set. MC_ID: 1 C_ID: 1

I have run my classification map in QGIS using the semi-automatic classification plugin or SCP. I want to use the same ROIs for different sentinel imageries. But I faced an error Error [24]: The ...
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1 answer
586 views

Validate a supervised classification in Google Earth Engine using ground truth data

I ran a supervised classification in Google Earth Engine (GEE) using the following script. // add an image, bounds, filter data and sort by cloud cover var limitiNapoli = 'PathToMyasset' var image =...
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"User memory limit exceeded" during Random Forest classification in GEE

I succeeded in an initial attempt at using Random Forest classification on my input image (an exported mosaic covering ~ 2,797 km2). I used 30 trees, classified based on 4 bands, and passed a training ...
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-1 votes
1 answer
727 views

Applying Otsu thresholding method to raster in QGIS

How can I apply Otsu’s threshold method to a Raster in QGIS for reduction of a gray level image to a binary image?
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5 votes
2 answers
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Computing Excess Green Vegetation Index (ExG) in QGIS [duplicate]

I have to process the image for Sugarcane row detection and extraction. Sample image is accessible from the link: https://github.com/AndresHerrera/croprows_generator_pa_v2/tree/master/droneimages I ...
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Memory issue loading raster into numpy array

I am trying to open a historical imagery tiff dataset into a numpy array so I can do some image processing on it afterwards. However, it gives me 'unspecified error' when trying to run the (very) ...
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1 answer
571 views

Normalising image bands in google earth engine before classification [closed]

I have an image that has four bands. Three of them are derived from Sentinel-2 to give NDVI, NDBI and SAVI. The fourth band is derived from a Sentinel 1 SAR image collection. The Sentinel 2 bands have ...
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