Questions tagged [algorithm]
A mathematical procedure used to solve problems with a series of steps. Algorithms are usually encoded as a sequence of computer commands.
585 questions
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Calculate max number of points within a geographic area with a minimum distance
I read the similar question/answers: Seeking algorithm to place maximum number of points within constrained area at minimum spacing?
However, it is more than a decade old, maybe something new evolved ...
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PYQGIS Processing Script - Add custom action to output layer
I wrote a processing script that creates a layer and adds it to the current project:
class TestAlgorithm(QgsProcessingAlgorithm):
def initAlgorithm(self, config=None):
self.addParameter(...
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Activating/deactivating algorithms in QGIS Model designer
I often work in QGIS Model Designer to automate tasks
s.
It is often useful to deactivate part of the model when working with large models. I can deactivate as many algorithms as I want at the same ...
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Can Data Edition Number in DTED files be empty?
I have an algorithm that gets 3600x3600 elevation matrix from DTED2 files. I have encountered a problem when processing some of the files. It seems that Data Edition Number value in Data Set ...
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Algorithm to convert old map sheet number and grid refs to lat and long - Irish Ordnance Survey 1/2 inch maps [closed]
I have a list of 80 locations from an ecological survey in the early 1980s, and they are referenced by sheet number followed by 6 figure grid reference.
The sheet numbers are of the Irish Ordnance ...
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How can I calculate the arrival time of a bus on a specific route?
I'm creating an app to track the location of buses in my city. My goal is to show in the app how long it will take for the next bus to arrive at a selected stop.
Each bus follows a specific route, ...
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No result from algorithm r.stats in QGIS
I don't understand why algorithm r.stats doesn't give me result in the sidepanel (show result); the error is 'impossible open the file'
What can I do to solve the problem?
I show you:
Versione di QGIS:...
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Set layer different style to multiple layer at once in model designer
I made a model that generates multiple layers
Among other entries, a style file is required as input that I use to set one of the output layer.
I would like to use a folder input and to set multiple ...
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Existing Algorithms for label placement with callouts
I am thinking to answer the question here: Label placement with callouts in QGIS.
I want to implement a kind of algorithm in python that will create 2 different columns [X and Y] that will be the ...
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Calculating distance between two points on line string
I have a line string and two points with me. I need to understand how to calculate the distance between two points along the provided line string. Also, note that in some cases, the provided points ...
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QGIS Processing Algorithms Fail After Second Execution with "Algorithm not found" Error
I'm encountering a persistent issue in my QGIS environment where Processing Algorithms fail to run after the second execution, consistently showing an "Algorithm not found" error. This ...
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Retrieving concentration values from Google Earth Engine
I am using a chlorophyll-a algorithm to retrieve chlorophyll-a and turbidity concentrations using different algorithms for a lake using Sentinel 2A (S2_SR). How can I determine the output ...
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Accessing previous algorithm outputs in QGIS graphical modeler [duplicate]
I want to extract features by expression in a graphical model in QGIS. I want to use the overlay_touches() function to extract features that touch those of another layer.
I manage to do this "...
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Generate a radius for a point, in order to count how many times a line passes through that radius
I am working on a project where I have to count the number of lines passing near a point. I plan to generate a radius around each point, since the lines do not cross the point, but pass close to it, ...
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ENDISI calculate
I'm new to ArcGIS. Can someone tell me why my ENDISI always equal to 1?
My algorithms:
("band02.tif" - 16170.19 * (("band06.tif" / "band07.tif") + "mndwi.tif" ^ ...
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Clustering Algorithms for Geospatial Data
I am new to the world of Geospatial Analysis!
I am interested in learning about Clustering Algorithms that can be used for Geospatial Data.
For instance, suppose I have:
A shapefile for all ZIP Codes ...
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Find areas distant from any points
I want to draw all areas that are far enough away from any single point of a layer, in this case they are Openstreetmap building=yes tags and I want to calculate the areas that are completely clear of ...
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How Neighbor Contiguity Algorithm actually works
I want to identify neighbors based on queen or rook contiguities in a programming language that does not have the feature yet. I know that tools like spdep, pysal, geoda, and ArcGIS all implement this,...
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How to check if there is an arc within a polygon (algorithm in geometry) [closed]
Now I have a polygon with arc like this:
I need to check if this polygon contains arc or not. How can I do that using geometry?
Clarification about the reason why:
I need to know how to detect in &...
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Crash when running algorithm via PyQGIS plugin
I use a Python plugin which is working great on my computer. But on another one, I get an error at the execution of an algorithm from processing package in PyQGIS:
## Report Details
**Python Stack ...
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Convert radar parameters to polygon
I have the following list of parameters for a given radar:
Latitude
Longitude
Coverage lateral
Coverage horizontal
Max Range
Power Emitted
I would like to convert these parameters to some type of ...
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Merge vectorlayers and attributes in QGIS
I am writing a script to run in QGIS and one thing I am trying to do is to merge a row of layers and their attributes. So if one layer is overlapping with another there should be created a new object ...
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Use polygon lines to create masks
Given a tile (the cropped base map in the left) and polylines (red lines), is there any tool/workflow in QGIS to convert them into masks in the right?
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Detecting and making all connected lines in the same direction in QGIS
I have a list of straight roads segmented which has a unique "ID". I would like to detect connected lines in the road network and make them in the same direction instead of reversing them ...
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Output singlepart features by default for tools and algorithms in QGIS
In QGIS, many algorithms and tools return multipart geometries. For further processing, a conversion Multipart to singleparts is necessary. This is a bit cumbersome.
To make just one example: when ...
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