28 votes
Accepted

Moving from Earth Engine image to array for use in sklearn

Ideally there would be some way to convert EE image objects to sklearn-readable NumPy arrays directly using the EE Python API. ee.Image.sampleRectangle() does this. However, there is a limit of ...
Justin Braaten's user avatar
16 votes

Distinction between pixel-based and object based classification?

As far as pixel-based classification is concerned, you are spot on. Each pixel is an n-dimensional vector and will be assigned to some class according to some metric, whether using Support Vector ...
John Powell's user avatar
  • 13.6k
14 votes
Accepted

Is it possible to set different scale dependent visibility for one layer classifications?

You need to use Rule based style to set the scale for primary, secondary and tertiary network, as you can see below (but with different data): You can double-click each styled label to get more ...
ahmadhanb's user avatar
  • 40.7k
13 votes
Accepted

What is the difference between sample, sampleRegions, and stratifiedSample in Google Earth Engine?

sample() uses 1 region (either points or polygons) and does exhaustive sampling in that region (all pixels) unless you specify a smaller number of points. But the random sampling it does isn't ...
Noel Gorelick's user avatar
12 votes
Accepted

Distinction between pixel-based and object based classification?

Your understanding is generally correct, however, there are dangers in your description of the object based classification - the term 'object' refers to the group of pixels, not whether or not it ...
Mikkel Lydholm Rasmussen's user avatar
11 votes
Accepted

Conversion from Raster to Vector in Google Earth Engine?

One giant Multipolygon per class isn't going to scale very well, but it's not hard to produce that. var geometry = ee.Geometry.Rectangle([29.1796875, 32.02670629333615, 32.607421875, 29....
Noel Gorelick's user avatar
10 votes
Accepted

Reclassifying raster layer with certain colors for value ranges in QGIS?

You may apply a reclassification by right-clicking on the layer in the Layers Panel and then clicking on Properties: from the dialog that appears, go to Style and then set these parameters (you can ...
mgri's user avatar
  • 16.1k
9 votes
Accepted

QGIS Gratuated Symbology gives differents results on every classification with Natural Breaks (Jenks)

Looking at the code, QGIS will take the exact values if there are up to 3000 features. Otherwise, it will take the largest between 3000 random features or a random 10% of the data.
JGH's user avatar
  • 41.6k
9 votes
Accepted

Performing supervised classification on Sentinel images

This is how I do it using QGIS - Geopandas - sklearn.svm.SVC. I have a Sentinel 2 satellite image which I want to classify into: Agricultural Clearcut forest Forest Mire Road Water Create truth data ...
BERA's user avatar
  • 71.2k
8 votes
Accepted

Can LiDAR differentiate between rock and soil?

In terms of something akin to a spectral signature, the only way would be through the return intensity values, which are rarely calibrated. Unfortunately, there is really nothing expected in the ...
Jeffrey Evans's user avatar
7 votes
Accepted

ArcPy command fails (pathname becomes corrupted) based on the starting letter of input file?

The problem is you need to be escaping the pathnames. In Python (and many other programming languages) the single backslash \ is an escape character. See this page for an explanation. in the path "...
crmackey's user avatar
  • 8,484
7 votes

Finding tree canopy width using PDAL?

First, for the answers proposed here, you probably do not want to use the ferry filter to push HeightAboveGround to Z, at least not prior to segmentation, as the act of normalizing heights involves ...
chambbj's user avatar
  • 108
7 votes
Accepted

Stratified random sampling with Google Earth Engine Error

Try using just the stratifiedSample algorithm: https://code.earthengine.google.com/e061f92736d8261f812db1dc2bfa8934 var ROI = ee.Geometry.Rectangle(-82.56277, 35.58935,-82.53436, 35.59996); // ...
Noel Gorelick's user avatar
7 votes
Accepted

Changing line width by classification in QGIS

You can use graduted stylings for color and also size when using point or line features. In case of lines the size is used to classify the width. There you find also the options for natural breaks and ...
Matte's user avatar
  • 6,235
6 votes

Determining bare earth DEM from unclassified LAS file?

This can be done with a pdal filter using either Simple Morphological Filter (SMRF) or Progressive Morphological Filter (PMF) algorithms. Quick pdal ground --cell_size=5 --extract input.laz out-...
matt wilkie's user avatar
  • 28.2k
6 votes
Accepted

Create Classes based on Field Values using Python in the Field Calculator

You need to use the Codeblock - see above your code box there's a button that says "Show Codeblock". Check that, and you can enter your code into the codeblock. def myReclass(overallUtil): if (...
Midavalo's user avatar
  • 29.7k
6 votes
Accepted

Evaluating training samples for supervised image classification in ArcGIS Pro?

ArcGIS Pro is still in the process of increasing it's toolset, that's an optimistic outlook, others have had similar questions in other forums, Where is the classification histogram? and ArcGIS Pro - ...
whyzar's user avatar
  • 12k
6 votes

Randomly splitting Feature Collection in Google Earth Engine?

Okay, I figured it out myself and want to share the answer for anyone else who has the problem. First, it is possible to split a feature class with the random column. My mistake was however to put "...
sarap's user avatar
  • 137
6 votes

Moving from Earth Engine image to array for use in sklearn

What I've done is download the images as tifs from GEE (something you might have to do in pieces given the size). I used the getDownloadURL() function because it is faster, For larger images use ...
la_leche's user avatar
  • 423
6 votes

Aggregate multiple image class values into a single class (Earth Engine)

Use the remap function. Just to give you an example, here I remapped your band values to ones and other values to zeros. // merge several clusters together // Define your from and to values var ...
Kuik's user avatar
  • 10k
6 votes

Classifying an image based on the EVI values of vegetation

EVIband.gte(0.6712).and(EVIband.lte(0.776) evaluates each pixel and returns 1 if the pixel value meets the conditions and 0 if not. If you want to give the pixels that meet this condition some ...
korndog's user avatar
  • 1,038
5 votes

Google Earth Engine, Supervised Classification

I'd do something like this: // Landsat 5 TM Raw Image Collection var lt5 = ee.ImageCollection("LANDSAT/LT5_L1T"); // Filter by date and location (Landsat Path and Row Designation) var ...
Rodrigo E. Principe's user avatar
5 votes
Accepted

Making a line from points but preserving classification of points in QGIS?

I don't know it is possible to achieve what you are asking because you don't know how to proceed when you pass from a category to another one. I will explain it with an example. You may try using the ...
mgri's user avatar
  • 16.1k
5 votes
Accepted

Creating graduated symbol classification based on values from multiple columns?

A click on the sum symbol next to the column choosing dropdown menu leads you to the expression dialog where you can easily combine all columns in almost any way you like, e.g. sum up all three ...
tallistroan's user avatar
  • 2,351
5 votes
Accepted

Categorizing multiple values_multiple atributtes - QGIS 2.14

There are several ways to achieve this purpose. You can always create rules for labelling, as you suggested, but you could try adding a new column to your file with the label for each desired class. ...
fabio.avigo's user avatar
5 votes
Accepted

Classifying LiDAR ground points using laspy?

I was able to come up with a solution. The following code works, but it feels like there is a much simpler way to do this operation. If anyone has a cleaner or more efficiect way to filter and ...
rosswin's user avatar
  • 371
5 votes
Accepted

A reproducible example for the use of separability measures in improving selection of spectral variables

The code you posted is not reproducible, so I'm starting from the classification example found in this introductory repo. It's also not clear what you mean by the "use" of separability measures. I'...
Nicholas Clinton's user avatar
5 votes
Accepted

SMILE classifiers/regressors in Earth Engine

The "Smile"-named classifiers in Earth Engine are basically the Smile v1 (we're not yet at Smile v2) classifiers, with the parameter names changed to match existing Earth Engine usage, and a ...
William Rucklidge's user avatar
5 votes
Accepted

Install Orfeo Plugin in QGIS - Plugin is not already in QGIS core

Instead of the Plugins Manager, you will need to work on Options (from the menu Settings > Options). In the Options window, select Processing section (lowermost tab). You will find the OTB. Expand ...
Kazuhito's user avatar
  • 30.7k

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