Questions tagged [polygonize]
The process of producing a polygon feature layer from a raster or from lines.
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QGIS: Should I convert raster dataset to vector and how?
I've a raster dataset of 20m² cells that show if a cell has been deforested and the year. I need to calculate the distance of each cell from a conservation project boundary, roads, canals (which are ...
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QGIS: Lines to polygons not working
I have +1000 CityGML data with building height that I want to convert to a raster mask for deep learning. So far, I have converted the GML data into GeoJSON with its respective ID as linestring. Now I ...
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Intersect a set polygons/multi-polygons at once and get the intersected polygon
I have a Geopandas data frame with five multi-polygons geometries. Now, I want to intersect all the geometries at once and get the intersected polygon out of it. I tried using unary union and ...
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Merge many small polygons into larger shapes
I'm trying to build a landcover layer from the ESA Land Cover dataset. So far, I have been able to convert the image data to a bunch of very small polygons. But for my use, I really just want a "...
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Validation of Vector Geometries to OGC Standards
I'm currently using FME to validate geometries, coming from 3rd parties, making sure there to OGC Standards.
I was hoping to be able to replicate these checks in QGIS, but find the tools available (...
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How to create a boundary polygon around raster extent (.tif) in QGIS
I would like to create a polygon around the raster (.tif) extent so I can calculate for instance the area in m2 within the polygon.
When I try to Polygonize or Clip raster by extend (and delete the 0 ...
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Polygonize a vertical plane defined by a MultiLineString Z in PostGIS
I have to polygonize a vertical plane defined by a MultiLineString Z:
SELECT ST_AsText((ST_Dump(ST_Polygonize(ST_GeomFromText(
'MULTILINESTRING Z ((
0 0 3,
1 1 3,
2 2 0,
...
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Remove small pixels in raster without leaving a gap
I have converted a raster to shapefile (polygonize) in QGIS and now have some areas that are salt and pepper with small points. I want to absorb these into the large polygon around the pixel (polygon)....
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Shapely polygonize over a MultiLineString returns 0 geometry
I need to polygonize a linestring feature.
To this end, I'm using the polygonize function of Shapely '1.8.5.post1' in Python 3.10.6.
from shapely import wkb, ops as sp_ops
wkb_str = '...
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Creating polygons from an RGB image in QGIS
I scoured the QGIS documentation and couldn't find anything.
What I am trying to achieve is a polygon covering a certain area, in my case, it's a glacier. The imagery of the glacier comes in the form ...
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Filter small raster areas computationally efficient (with R/gdal)
I have a large geotiff with NDVI differences (values -10'000 to +10'000), that I use to create polygons. My workflow currently is to polygonize a binary mask of it and then filter areas that are too ...
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QGIS - How do I select features in a particular location precisely, the location is a raster
I have polygon data that is data retrieved across whole world, how do I focus this data on a raster map. Basically I want to select the features only in this area but I want it to match exactly this ...
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QGIS - Converting Vector to Raster and back to vector to resample resolution of vector data
I would like to convert my polygon data into a raster file to change the pixel resolution and then would like to convert it back to polygon data since this will allow it to be resampled to another ...
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How to convert mask in netCDF to one polygon shp, with QGIS/GDAL polygonize or python?
I made a 0-1 mask in netCDF, with coordinates lat lon. The mask itself looks like:
0 0 0 0 0 0 0 0
0 0 1 1 1 0 0 0
0 1 1 1 1 1 0 0
0 0 0 0 1 0 0 0
0 0 0 0 0 0 0 0
I have succeeded to read it, ...
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Transform Lines to Polygons QGIS - FEMA SFHA
I am very new to GIS. Using QGIS LTR 3.22
I have downloaded the FEMA SFHA Shape files from FEMA's website. There are a few layers but the specific one I am working with is the S_FLD_HAZ_LN layer.
...
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no feature ID when polygonizing raster with python GDAL
I'm trying to polygonize the following binary raster:
The output is a polygon layer (ESRI shapefile) that looks good, however, doesn't have FIDs for the features and thus I am not able to iterate ...
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136
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Polygonize tool error "Process gdal_polygonize.bat failed to start"
I am trying to use the Polygonize (Raster to Vector) tool on QGIS-LTR on Windows 11.
When I launch the tool on a layer I get the following error.
Input parameters:
{ 'BAND' : 1, 'EIGHT_CONNECTEDNESS' :...
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Polygonize/Vectorize large raster
A raster(.tif) of 6.70GB needs to be converted into polygons. The raster is binary (0 & 1), currently I am using Polygonize (raster to vector) and its taking a considerable amount of time and the ...
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QGIS Polygonize not working on large dataset
I have a 1.3 gigabyte shapefile I am trying to run through the vector polygonizer in QGIS. The lines intersect each other yet when I run it through it gives me "No polygons were created." Is ...
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127
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Polygonizing global raster using Python/GDAL?
I'm looking to polygonize a global raster with 29 different categories. However, when I try to run it in QGIS, it either crashes or takes forever to load.
I'm now trying to run it in python.
import ...
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57
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Classifying areas after feature to polygon
I am trying to classify areas based on the polygons created from using two separate lines as input in ArcGIS Pro's Feature to Polygon tool. The input looks like this first column in the image from the ...
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43
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Polygons from lines with manually completed lines using vertex tool and snapping
I have a vector layer of lines (contours) which was a model output. Some contours are incomplete due to land barriers (necessary for the model) which produces something like this
I have used the ...
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376
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Converting complex depth contours to polygons in sf and R
I have a large dataset of depth contours downloaded from an open database. At the time of writing, these contours appear to contain the best available continuous depth model for my region of interest. ...
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1
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Convert area between LineStrings to Polygon in shapely
I need to create a Polygon from the area enclosed by four LineStrings with real world data in shapely. In this example, I want to polygonize the area between b1, b2, t1 and t2.
import shapely.wkt
b1 = ...
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271
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Joining a very large raster and shapefile in QGIS
I am using a very detailed 30 m x 30 m raster on deforestation (found here: https://storage.googleapis.com/earthenginepartners-hansen/GFC-2020-v1.8/download.html), I want to do all my analysis at this ...
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How to extract the boundaries of Shapely MultiPoint? [closed]
I have a shapely MultiPoint object but need to extract the boundaries into a Polygon object.
I'm currently using the convex_hull of the MultiPoint object but my MultiPoint sets can have sharp inward ...
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386
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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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How to apply GDAL polygonize?
I am desperately trying to vectorize raster files in a loop for which I came across GDAL's polygonize function (https://gdal.org/programs/gdal_polygonize.html).
However, I don't get the hang of it. To ...
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How to polygonize NDVI raster using GDAL?
I have raster with NDVI values. I would like to polygonize the raster to get vector where each polygon is a pixel.
I have tried gdal.Polygonize as described in the documentation and that runs without ...
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351
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PostGIS: Split polygons into intersecting and non-intersecting and grouping on overlap
I have a big query that I am looking to optimize. I am matching millions (expanding daily) of rows with Points against a mostly read-only table of (tens of thousands of) areas with (Multi)Polygons. ...
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Saving polygonized raster file to shapefile failed
I have a raster that I have polygonized (raster to vector) with QGIS 3.20.3. The result is a temp layer that can be displayed in the canvas.
When I try to save the features to shapefile it runs until ...
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507
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How to get float values instead of integers when polygonizing rasters using QGIS?
I'm using QGIS 3.16.13-Hannover to convert a TIF file (solar radiation grid cells) into a vector like a Geojson or Shapefile. I was confused that everytime I ran the polygonize workflow in QGIS, I was ...
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Calculate area for each raster value within a polygons (python) [duplicate]
I have a raster file and polygon shapefile. I need to calculate area for each raster value within a polygons.
Example: the polygon below Total area = 1000 ha. I need an area for each raster value in ...
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192
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How to add a border around a GeoTIFF?
I have a 200x200 GeoTIFF from which I am trying to create multiple polygons. I am using different range values to generate different polygons. However, the inverse of the polygons I want are being ...
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gdal_polygonize / QGIS Polygonize creates
The original data is a pdf converted to tiff then georeferenced.
Then i did the sum of the 3 colors band to simplify the calculus
When i launch the polygonise (raster to vector), this is very slow ...
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Looking for QGIS equivalent of ArcGIS "Feature to Polygon" tool
I am looking for a tool (a workflow) in QGIS that does exactly the same as the "Feature To Polygon" in ArcGIS available with the Advanced license.
I have seen a related question Seeking ...
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139
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Extract altitude bands (polygon) from DEM (GeoTIFF)
I'm trying to extract altitude polygons from a DEM - 0 to 1000m, 1000 to 2000m, etc.
I'm not sure what this is called (noob question, yes I know), and can't find help that points in the right ...
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129
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Extracting all possible polygons from set of different types of geometrical elements
I have an input, a set of different types of 2D geometrical elements with all its attributes (arcs, circles, lines, polylines, rectangles, polygons..). These elements can be connected end to end, ...
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"Layers were not correctly generated" error when polygonizing raster in QGIS
I have the raster of a river product of an image classification with the SCP Plugin, and i need to divide the land and the water that resulted of said classification, so i am attempting to polygonize ...
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Split layer with lines or with Polygonize (and keeping all features intact) - QGIS 3.18
I want to divide a polygon layer into different smaller polygons.
I started by converting the main polygon into a line, then I used the Add line feature to draw the lines. Then I used the Split with ...
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125
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NLCD 2016 Data in QGIS
I am struggling to convert the NLCD 2016 data to a shapefile in a CRS of WGS 84. I have three problems (that I think are simple) that I would love some help with:
(1) It seems other's have the option ...
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How to polygonize raster with range of values?
I have a raster with range 0 - 1. I want to polygonize them in QGIS according to their value to be later classified from "Very Low" to "Very High".
raster_value
...
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209
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QGIS converting multiline layer into polygon doesn't work properly
I would like to polygonyze my layer.
It includes between 6-20 separate lines.
I was following the hint here:
Converting line to polygon using QGIS
but at some point I've got an error:
Feature (2) has ...
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132
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Splitting Vectors with Raster Layer
Does anyone know of a method to split vector data based on a corresponding raster layer.
For example, I have a classification with two classes and have an overlaid vector layer as seen in the image ...
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100
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Making polygons from interpolated points in QGIS
I need to know the extension of the area of a lagoon according to depth classes. I started from a point shapefile containing depth values and used the interpolation plugin and I obtained a raster file....
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214
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Very slow segmentation using Python
I used both Python and QGIS to perform polygonization of a raster but the waiting times with Python are very long, while with QGIS the operation is done in a few seconds.
Could you tell me the reason ...
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69
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Reclassifying and vectorizing specifc classes in Google Earth Engine
My raster file has 29 classes and I applied 'Reclassify by table' in QGIS 3.16 to assign 1 to classes 15 and 24 only and all other classes were classified as 0.
I applied the following script to ...
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385
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Too many edges error on GEE
I have this code that works perfectly for small rasters.
var image = ee.Image("users/parivash89/Cuneo_Reclassify")
.toInt();
Map.addLayer(image);
Map.centerObject(image);
var classes = ...
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130
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Google Earth Engine_Conversion to vector
I have a classified geotiff raster that has two classes 0 and 1. I changed its type to int and imported it from my computer to GEE using upload a new asset and I changed its var name to image and I ...
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Ways to speed up Polygonizing of rasters/orthophotos (binary)?
From a orthophoto of the Wadden Sea, I want to create a polygon from a class of this TIFF/raster (binary) representing an oyster reef, calculate the area of the reef and form a polygon around the reef ...
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