Questions tagged [area]
Area is a quantity that expresses the extent of a two-dimensional surface or shape, or planar lamina, in the plane.
672
questions
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25 views
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 ...
0
votes
0answers
9 views
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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1answer
70 views
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([...
1
vote
0answers
23 views
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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0answers
16 views
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 ...
5
votes
4answers
456 views
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 ...
4
votes
5answers
421 views
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 ...
0
votes
1answer
17 views
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....
7
votes
2answers
88 views
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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0answers
83 views
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 = ...
1
vote
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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1answer
35 views
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 ...
2
votes
2answers
73 views
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 ...
0
votes
1answer
29 views
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 ...
8
votes
1answer
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 ...
2
votes
1answer
83 views
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 ...
1
vote
1answer
39 views
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?
0
votes
0answers
90 views
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/...
14
votes
2answers
329 views
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 ...
0
votes
0answers
46 views
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 ...
0
votes
0answers
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 ...
0
votes
1answer
21 views
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, ...
2
votes
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 ...
0
votes
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 ...
3
votes
1answer
57 views
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 ...
1
vote
0answers
28 views
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 ...
3
votes
1answer
74 views
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 ...
2
votes
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 ...
0
votes
0answers
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 ...
3
votes
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 ...
4
votes
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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0answers
29 views
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 ...
0
votes
0answers
24 views
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). ...
2
votes
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 ...
0
votes
0answers
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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vote
0answers
47 views
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 ...
1
vote
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 ...
1
vote
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.
...
3
votes
0answers
28 views
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,...
1
vote
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 ...
0
votes
0answers
22 views
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 ...
2
votes
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 ...
0
votes
0answers
38 views
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 ...
0
votes
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.
0
votes
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
1
vote
1answer
51 views
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....
1
vote
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 ...
1
vote
0answers
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 ...
2
votes
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 ...
2
votes
0answers
29 views
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 ...
