Questions tagged [area]

Area is a quantity that expresses the extent of a two-dimensional surface or shape, or planar lamina, in the plane.

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Area calculation error [closed]

When I calculate the area with the QGIS program, the area comes out strangely. The results that worked well in the past became strange after reinstalling the program. Can you tell me why the area is ...
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NDVI, the vegetation index in landsat data [closed]

I calculate the NDVI from Landsat8. I masked the vegetation with a threshold. but I couldn't calculate the area of the green venation in hectares or in square kilometre. How can I calculate the area ...
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Dividing polygon into given number of equal areas in OpenLayers

I'm using a Style with Stroke and Fill to have something like this for Polygon: const feature = new Feature( new Polygon([ xPos.map((x, index) => { return transform([...
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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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Updating fields automatically in attribute table [duplicate]

I am working in QGIS 3.16 and I would like to know if it is possible to automatically update the fields. For instance I have a polygon shapefile with a field that indicates the area. I used the field ...
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Calculating polygon area within other polygon using Python

I have a polygon GeoDataFrame 'Polygons' with attribute "AREA" (total polygon area in ha) and another GeoDataFrame 'Small_polygon' with smaller polygons within the 'Polygons'. How do I ...
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Calculating polygon area in QGIS without adding new field

Is it possible in QGIS to quickly calculate the area of a polygon using a Processing tool, plugin, script without adding attributes or creating a new layer? Something launching the results window or ...
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1answer
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Google Earth Engine - Area is undefined to used in if

I'm having trouble getting my if to recognize the value of the area. When utilize .type returned undefined Code doesn't return response I tried: ee.Number .float .int var ar1 = a1.area(); var ar2 = a2....
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Classifying raster layer by number of equal values in given area using QGIS

I am using QGIS 3.16.12 - Hannover. I have a binary raster layer which consists of 2 values, either 0 or 1 (in my screenshots, 0 = black, 1 = white). The 1 values are scattered throughout the layer in ...
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How to calculate the area of a polygon in real meter in OpenLayers?

I'm trying to figured out why I'm getting weird results from ol/sphere/getArea. I draw an rectangle with fixed size of 5x5 meter. To translate 5 meters to map units, I do the following: const factor = ...
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1answer
42 views

How to create a histogram of areas of clustered S1 image in Google Earth Engine?

I am using S1 images and clustering in Google Earth engine to identify different land uses. I clustered using ee.Clusterer.wekaKMeans(5).train. Now I want to create a histogram that shows the area per ...
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Calculate within a buffer around a point the % of area covered per category

I have to calculate within a buffer of 10 m around each sensor (and later 50 m, 100 m, 100 m...) how much % of the area in that buffer is covered by each Landscape Element (LE). The goal? An attribute ...
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Calculating how much of polygon is within certain boundary in QGIS

I work for a local authority and I'm measuring the surface area of river catchments inside our local authority. I have a polygon layer showing me the catchments but a few of them go over our boundary ...
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Calculating total area of polygons by attribute, cut by another polygon

I am using QGIS 3.16. I have Natural Englands Priority Habitat loaded, I want to produce stats for five polygons I have in a seperate shp file of area of each habitat type in each polygon to produce a ...
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322 views

Calculating area of lat/lon polygons without transformation using GeoPandas

This question has come up several times, yet most solutions depend on a transformation to an equal area CRS. These solutions can be slow with large amounts of polygons, and also not accurate in high ...
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How to determine a polygon's area in a metric unit?

I have created a square grid and I would like to figure out the real world area of each polygon in a metric unit e.q. square metres via GeoDataFrame.area. import geopandas as gpd from shapely.geometry ...
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Loop through multiple vectors, calculate area for each, output CSV

I have 20 vector shapefiles in QGIS. I want to calculate the area for each one without doing it the manual way. Is there a way I can loop through each one, and output a CSV of each vectors area?
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Calculate/sum area (in hectars) of each pixel value within polygons of a shapefile using GEE Python API

I'm using the Land Use/Land Cover dataset of Brazil produced by MapBiomas, specifically the age of secondary vegetation available at projects/mapbiomas-workspace/public/collection6/...
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Why accurate area of all countries cannot be obtained using a single EPSG code, even if it corresponds to an equal-area projection?

I would like to check if using different equal-area projections lead to near-identical area estimation for a list of countries. Importing modules: import numpy as np import geopandas as gpd import ...
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Calculate surface area on raster using Python

I have raster files (GeoTIFFs) and would like to calculate the surface area. I envision having a way to extract the coordinates at each corner of the pixels, then have the height values for each pixel ...
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62 views

Calculating the area on the surface of the Earth from the intersection of two polygons using Python

I have made a program that calculates area and perimeter based on 2D coordinates (latitude and latitude) given by the user, asking if they want to include more coordinates from the third pair, and ...
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1answer
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Issue with area calculation in Google Earth Engine

Using this code https://code.earthengine.google.com/36d0af209d34063ff109c57c40d1901e I calculate the area of pixels inside a set of 5km radius Features. From the code results printed in the console, ...
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1answer
62 views

Calculating net area in ArcGIS Pro [closed]

I'm working with California wildfire data (1990-2020) in ArcGIS Pro. There are about 8,400 fires in the dataset. The acreage of each fire is included. I think it is highly likely that some land has ...
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1answer
25 views

Unable to intersect polygons in R even though CRS matches?

I am trying to use areal interpolation to distribute the values from a source polygons layer into smaller, differently-shaped polygons from a target layer, and have been unable to do so. I have been ...
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Adding new row by command in field calculator in QGIS

I am actually trying to create a new field in a table with the Model Builder (Field calculator function). Is there a command that creates a new field, so I can do calculations directly in that new ...
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Calculating the area individually enclosed by multiple contour lines in R (SpatialLinesDataFrame)

Aim Calculating the area and perimeter of each individual contour line (SpatialLinesDataFrame) extracted using raster::rasterToContour(). Issue In spite of my web searches, I seem I cannot find a ...
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1answer
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Area of intercepted geometry

I have a polygon layer and a point layer (which was created by obtaining the centroid of each polygon in the polygon layer). I have tried to use the aggregate expression to automatically fill a field ...
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1answer
31 views

Why is the calculated area different in the layer that was clipped with a mask

I have a mask that I created. I used calculate geometry in the attribute table to calculate the acres of the polygon (1,214,784 acres). I then used the intersect tool with the mask and another layer ...
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47 views

Behavior of distances and areas when Plate Carreé projection is applied to ellipsoid reference coordinates

Disclaimer: I am a Data Scientist, so bear with me regarding GIS knowledge. I am working with a raster dataset that is Plate-Carrée projected using EPSG:4326 as a CRS. Pixels are rendered via an ...
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2answers
66 views

Performing area weighted interpolation in QGIS

I have encountered a problem that I thought would be much more simple than I see it actually is, and conventional clipping did not work. I have the following grid layer with different values of a ...
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1answer
147 views

Calculating area of polygons without script in QGIS Field calculator

Whenever I click the Field Calculator in the attribute table, I am prompted to created a script in order for it to calculate the area of a polygon. However, I do not want to use code in obtaining a ...
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ArcGIS Desktop 10.7 tabulate area outputs blanks or zeroes in zone field

I am tabulating the area of HUC10 polygons (a little over 4,000 of them) using LandFire raster biophysical classes, but everything I have tried outputs a zone field that is either blank or full of ...
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ArcGIS Pro using Tabulate Area tool to summarize individual areas within polygon but areas too large

I used the Tabulate Area tool to find the areas of each land use type inside the circular polygons but the numbers I am getting make no sense (they sum to be larger than a circle with radius 500m). ...
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1answer
52 views

Area/perimeter calculations in table

In ArcView3.2 I used Xtools a lot, just click and it calculated area/perimeter for every polygon, in QGIS I am choosing column and write $area after the "Epsilon" + update. Is there some ...
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28 views

Controling accuracy of polygon data using ArcMap

I have a question regarding polygon data. I implemented "Calculate geometry" and the new column includes the area of interest to ha. The problem is with the accuracy of the data. The site ...
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Polygon area calculation returning 0.0 QGIS

I am trying to calculate the areas of these 12 individual polygons. However, when I run the area calculation, two of the polygons return 0.0 - whereas the calculation works for the other 10? Why is ...
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1answer
63 views

Creating raster with specific value cells of certain size in QGIS

I have created a raster containing cells with 2 values (1 for content > 0.65 and 0 for all other values). One cell is 25x25 m. I ran r.neighbor to find out which cells are in the neighborhood of ...
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1answer
65 views

Calculating area and projection using QGIS

I am facing problem calculating area and projection in general, using QGIS 3.18.3. preface: I am using EPSG: 32643 projected CRS. I aim to compute area and the result is fine correct in this image. ...
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Change number of default vertices in circles

I would like to change the number of default vertices per quarter circle QGIS creates/uses when running tools. Background I need to do some area calculations for circles and polygons containing curves,...
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1answer
195 views

Creating single polygon from GPS coordinates and finding its area with Python

I need to create a polygon and draw it on the map from GPS coordinates. The GPS coordinates are taken from the android phone while the land leveler working the crop fields. The results are not ...
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County area calculated from NLCD rasters is too large (with R)

I'm trying to calculate landcover repartition for each US county. I have obtained NLCD for the Apache county using the FedData package (devtools version) and I'm using county shapefiles from the ...
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1answer
89 views

Calculating area from DEM value range in QGIS

Is it possible to calculate the area of a DEM in specific value ranges, e.g. the total area between 200 and 300 meters of elevation? Using QGIS and my DEM is 1m. Would like to do this for my DEM, so ...
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Why has the total area of polygon been reduced after using the splitting tool in QGIS 3.16.6?

I am using the splitting tool to split an original polygon (survey boundary) into smaller polygons (vegetation types). When I sum the total area of the shapefile after splitting (all the veg types) it ...
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1answer
38 views

Calculating the area of the total buffer in QGIS

I'm struggling to find out how one should calculate the total area of the buffer in QGIS. I'm doing a home range analysis by using buffer. But I need to find out the total area as well.
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1answer
30 views

How to calc area using OpenLayers with UTM coordinates

I just need had a point format like below (zone,x,y) and need to calculate it's Area. 39,553816,3791942 39,548052,3731376 39,637947,3711980 39,616343,3808591
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Accuracy of raster cell size area to real world area

I read from somewhere here that a UTM raster's pixel count ratio is 1 pixel = 1 meter. I am working on a raster that says the island is 4.03 km² in area but a quick google search says the island is 4....
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1answer
51 views

Unit of $area in the field calculator in Albers Equal Area projection (ESRI: 102033)

I need to find the area of a set of polygons that are spread across South America. I researched a bit, and found that the Albers Equal Area projections reduces distortion and can be used for ...
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96 views

Calculate the area of a polygon on the surface of the Earth

I'm trying to write a function that will accept an array of coordinates and calculate the area of the polygon. function getArea(lat_long: Array<LAT_LONG>){ lat_long.push(lat_long[0]) const ...
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1answer
64 views

Compare two layers and find the percentage of the shared areas that are different between them

I have two shapefiles that identify flood zones for the same general area but in different years. The maps, however, do not cover exactly the same geographical areas (e.g., shapefile 1 covers counties ...
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Calculating the area of oyster drone imagery

I'm working on analyzing the area of an oyster reef and its development over the past years. The shown ortophoto is already loaded in QGIS. The unit of this file is degrees. That's where my main ...

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