38 votes
Accepted

Panchromatic Image association with high spatial resolution

Panchromatic images are created when the imaging sensor is sensitive to a wide range of wavelengths of light, typically spanning a large part of the visible part of the spectrum. Here is the thing, ...
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  • 10.8k
30 votes
Accepted

Splitting .tif image into several tiles?

I propose two solutions: the first one using QGIS, the second one using Python (GDAL). Solution using QGIS In QGIS you may create a VRT mosaic. Please follow this procedure (see the image below): ...
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  • 15.6k
14 votes
Accepted

completing satellite imagery tiles when data coverage is less than 100%

For images of the same location but different dates, I would rather talk about compositing than mosaicing (which combines images from different extents into a larger image). You will find a lot of ...
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  • 48.7k
10 votes

Ditch Extraction using LIDAR DTM (1m resolution)

I've had to map ditches from 1 m LiDAR derived DEMs of agricultural landscapes before. It's certainly a challenging task to come up with a workflow that is suitable. You're ability to successfully ...
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  • 10.8k
10 votes

Is it scientifically correct to pansharpen landsat reflectance product with pan band

Fundamentally the question here is "what does 'scientifically valid' mean". If you are looking to do spectral modelling on the data, then the answer is possibly different than if you are looking at ...
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10 votes

Counting rocks of different sizes on shoreline using ArcGIS Desktop?

For the most part not an ArcGIS answer but you could try it anyway since it is completely free software. You could try using scikit-image. You will get it if you install Anaconda (with Anaconda you ...
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  • 53.9k
9 votes
Accepted

image segmentation of RGB image by K means clustering in python

I hacked together a solution for this and wrote a blog article a while back on a very similar topic, which I will summarize here. The script is intended to extract a river from a 4-band NAIP image ...
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  • 50.4k
9 votes
Accepted

SAR - Using the Intensity or the Amplitude for the classification

The intensity image should be used for calibration and subsequent classification of geophysical features. To radiometrically calibrate the intensity, use the Calibrate tool in the Sentinel-1 Toolbox (...
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  • 1,624
9 votes
Accepted

"Copy" Image coordinates to another image that is nd.array

Save result array (rf_array) as in the following lines: rf_array = df_join['Prediction'].values # returns numpy.ndarray rf_array = rf_array.reshape(img.shape[0], img.shape[1]) # rf_array = rf_array....
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8 votes
Accepted

Should I always choose Sentinel-2 atmospheric-corrected imagery?

Atmospheric correction is particularly usefull if you need consistency between dates and/or adjacent tiles. Some studies showed that the use of atmospherically corrected images improve the subsequent ...
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  • 48.7k
7 votes

Unsupervised raster classification using GDAL

Scikit-learn has some excellent unsupervised classification/clustering algorithms. The batched K-means algorithm works quickly with large datasets. Here is an example using the KEA file format. You ...
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  • 805
7 votes

image segmentation of RGB image by K means clustering in python

You could look at clustering in scikit-learn. You will need to read the data into numpy arrays (I'd suggest rasterio) and from there you can manipulate the data so that each band is a variable for ...
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  • 15.4k
7 votes

Random Forest land cover classification in ArcMap?

I am the main developer of MGET. The first step in your problem is to obtain values of the covariates that you will use to fit the model to your 90 GPS points. It sounds like you want to use the 8 ...
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7 votes

Calibrating Landsat Level-1 Precision and Terrain (L1TP) corrected data?

The three sensors are all slightly different. However the OLI/TIRs setup is a marked departure from the TM/ETM+ sensors. The changes are succintly summarised by Li et al. 2013 as the: replacing of ...
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  • 2,036
6 votes

automatically geo- and ortho- rectify raw Landsat data using DEM

Answer for others so confused people as I am: To know how to deal with downloaded raw Landsat data - what else in pre-processing do I need? Firstly check their processing level in_MTL.txt file (...
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  • 3,276
6 votes
Accepted

Verifying landsat reflectance values?

Your question is two-fold. With regards to the actual atmospherically corrected data: there is no simple method for testing if the calculated reflectance values are right. However, the simplest ...
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6 votes
Accepted

Otsu thresholding and classic image processing algorithms on radiometrically calibrated Sentinel-1 SAR images

Otsu's method does not really care about actual values since it tries to minimize the total variance within classes while maximizing the distance between the classes. So, you could just run Otsu on ...
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  • 166
6 votes

Splitting .tif image into several tiles?

Don't split You gdalbuildvrt, you can create virtual tiles that will only use a few bytes on your disk. Then you can use most softwares that will take your vrt's as input to perform your processing. ...
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  • 48.7k
6 votes

Splitting .tif image into several tiles?

Another solution using GDAL is the gdal_retile.py tool: mkdir image_tiles gdal_retile.py -v -r bilinear -levels 1 -ps 20000 20000 -co "TILED=YES" -co "COMPRESS=JPEG" -targetDir image_tiles ...
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  • 1,250
6 votes
Accepted

What is lost when converting 12 bit imagery to 8 bit?

I know that you have tried to frame this as a general question, rather than specific to SPOT 6/7, but it's really a little of both. The naive answer to the "general" question "what is ...
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5 votes
Accepted

Filling in missing values in raster using R

I am the author of the R package gapfill, which is a flexible tool to predict missing values in spatio-temporal remote sensing data sets. https://CRAN.R-project.org/package=gapfill It could be helpful ...
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  • 211
5 votes

Failed to create signature file

I had some success by changing the target directory to which I saved the signature file. Rather than using the server space I had been alloted, I chose the local desktop, and it worked without a hitch....
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  • 51
5 votes

How to Read&Write .tiff images in java using GDAL library

I guess you have gdal and the bindings installed, and some coding ability, so I'll just provide an outline: import org.gdal.gdal.gdal; import org.gdal.gdal.Band; import org.gdal.gdal.Dataset; ... ...
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  • 12.5k
5 votes

Estimating vegetation composition from digital images

Yes, there are free object-oriented (segmentation) software available. A few that come to mind are Spring, ITK, Orfeo toolbox and GRASS GIS. I would however point out that image segmentation is a ...
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5 votes

How to perform an accuracy assessment in eCognition?

I would follow as below in version 9: Use sample selection algorithm(use brush and set class) and select samples and save these layer as TTA mask Then you can generate TTA mask from sample Now you ...
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  • 3,456
5 votes
Accepted

How to suppress noises of this edge-detected image?

I think you can do some thresholding if you stretch your histogram. In the example below, I streched it between percentile 2 and 98 and set a treshold at 250. It looks like a start. import numpy as ...
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  • 322
5 votes

Pansharpen landsat mosaic in Google Earth Engine

You can mosaic a collection of pan-sharpened images as follows: // Function to mask clouds using the quality band of Landsat 8. var maskL8 = function(image) { var qa = image.select('BQA'); /// ...
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4 votes

Image classification using google satellite images

The first thing you will want to do is look at the Google Terms of Use and Licensing. Google is very particular on how their data and software can be used. I would look at this first as it may be a ...
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  • 9,253
4 votes

gdal : How to restore georeferenced DEM's metadata?

Probably the easiest thing to do is use gdal_translate to create the resized image with something like: gdal_translate -outside 50% in.tif in.small.tif But if you do need to use ImageMagick, try ...
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  • 16.2k
4 votes

Extract values from raster based on points and pixels adjacent to the point

You appear to be looking at a suite of software options. A way of doing it in ArcMap model builder using off the shelf tools could be: point to raster (ensure snap to raster environment is set.) ...
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  • 39.7k

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