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 of extent changes at when cell size increases

I am working with a LiDAR dataset that has been converted from a set of .txt files into an XYZ point feature, and then interpolated using Topo To Raster. When the cell resolution is set to 1 meter, ...
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1 answer
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Using GEE to investigate area of Desert returns wrong area

I am very new at GEE and am trying to investigate how much of Chad is desert using NDVI. I presumed using Reducer.count() to count the number of pixels and then multiplying it by the scale would give ...
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Calculating area that polygon occupies within another polygon using QGIS

I am using QGIS. How do I calculate the area that polygons (such as those brown and red ones) occupy within the area of that "more pink" polygon?
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QGIS find areas of intersection of overlapping polygons

I have two shapefiles, one corresponding to census tracts and the other is precincts. I'd like to find the proportion of area of intersection of each precinct with every tract that it overlaps with. I ...
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1 answer
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Creating polygon by specifying area and some (irregular) boundaries

To assist with a multi-year planting project, I need to find a way to identify and map the portion of the whole planting area that will be planted in year 1. With reference to the image below, the ...
2 votes
1 answer
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Calculating the area within a polygon of a different layer

I am trying to calculate the area ('area' - pink/red colored) of the Layer ('Layer1') within a polygon of a different Layer ('Layer2' - yellow selected). I`ve tried to calculate it, within the layer2 ...
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Average slope (in °) for each area

I have nationwide areas I want to get the average slope in ° in a south-north line for each area. I found something about zonal statistics in QGIS and DEM (enter link description here) but returns ...
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Determination of distances (for PV-Moduls)

I located nationwide suitable areas for photovoltaicmoduls. Since the possible installable PVmodule-area depends on gradient of the ground, the distances (in blue see below) between the two ...
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2 votes
1 answer
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Calculate value per unit area from raster in QGIS

I have a raster (GeoTIFF) of number of people per pixel. I would like to convert this to a new raster of population per unit area. In other words, I would like to divide each value in my existing ...
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1 answer
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QGIS calculate area automatically

Is there a way to calculate area automatically when I edit a polygon? I mean, is there any function there I can use on area field and update itself when I finish editing?
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ipyleaflet area of drawn polygon

I am trying to get the area of a drawn polygon in ipyleaflet with geopandas...but kind of cant get a propper result. from ipyleaflet import Map, basemaps, DrawControl, SearchControl m = Map(basemap=...
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Calculate the percentage of a polygon either side of a line

I have a series of polygons outlining distributions of various fish species around Australia. I am relatively new to GIS. I am trying to class each species as either tropical or temperate based on the ...
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Calculate the area of pixels with values below 0 in NDVI

I'm relatively new in GEE. I'm trying to calculate areas of different type of classification in GEE and I'm having a problem with it. The script code is: https://code.earthengine.google.com/...
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Calculating Raster Cover in Polygon - ArcGIS Pro

I need to work out how much tree cover is in a polygon. The tree/vegetation layer is a raster with non-integer values for height (the Environment Agency VOM data if anyone's familiar). Height values ...
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Area calculation doesn't make sense: smaller raster has higher area

I'm comparing two rasters calculating their area. One of them is noticeably (see image below) larger than the other on the map. But when calculating the area, the one that looks smaller gives a larger ...
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1 vote
1 answer
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Calculate polygon area in vector grid QGIS

I have a polygon layer in QGIS (building outlines) and I made a grid over this layer using the MMQGIS function. I want to calculate the area of the building outlines in each grid cell (so it becomes ...
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Calculate new aggregated data using given aggregated data for different geographical unit

I have data aggregated (mean) on the neighbor level. And the same region is clustered using some criteria, and the relation is a new geographical unit. Are there approaches to calculating the ...
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Calculating area's region in DEM

I have a DEM map in my project Tsunami Assesment project.The white area below the mentioned map is sea and we know that possible tsunami height is 14 meters(please neglect the line, there is an error ...
2 votes
1 answer
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Checking surface area of com.vividsolutions.jts.geom.Polygon

I would like to compare the area of a polygon created with some coordinates passed and ensure that it is less than half the sky or a set area. My approach to create the Polygon is as follow: Geometry ...
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Finding intervals of latitude/longitude of cities throughout the world at 0.01° precision [closed]

Geographical coordinates determine a specific point on a map. I am searching for the coordinates interval (thus to frame the area) of different large cities by latitude/longitude at a 0.01°x0.01° ...
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Calculate area for raster in R

I want to calculate area for each different class of landuse for raster image as shown below:- The dimension of the raster image is as follows: class : RasterLayer dimensions : 16366, 29848, ...
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2 answers
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Calculate area of adjacent pixels

I have a raster layer of seasonal lakes created from snowmelt runoff. I would like to calculate the size of the lakes that are created. So I want to basically calculate the area of pixels clustered ...
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1 answer
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Parallelize raster area calculation per class in R

I am trying to get crop area for admin units of whole African continent using the data available here at 30-m spatial resolution globally (raster value 1 = crops). I've tried both terra and raster ...
2 votes
1 answer
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Calculating cumulative sum of area values in attribute table by graphics in QGIS

In QGIS I have a set of polygons divided into plots, each polygon has a diameter and area. I would like to sum up the polygons per each plot area. From the attribute table, the polygons are not ...
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Open standard of Earth areas

I have used a "proprietary" 3 dimensional shape for dividing the Earth's surface into similar sized areas of about 1000 km2. It is a icosahedron (or maybe a pentakis dodecahedron) with the ...
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3 votes
1 answer
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Area calculation for non-planar surfaces

I am looking for a way to calculate the area for a big set of 3D-surfaces. I know, that some of those surfaces are slightly non-planar, which means that the coordinates got somehow "rounded" ...
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Road network analysis for big data

Is it possible to generate service areas from 65000 facilities? Batch processing or database analysis? A friend tried with 6000 (1/10) facilities, OpenStreetMap data (country Latvia) to calculate ...
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Calculating volume of IDW raster below Height of Plane, but it is failing

I am using ArcMap. I am trying to calculate the volume of water using IDW Tool. When I reach a point to calculate, the statistics below height of plane cannot run, giving me 0.00, What could be the ...
2 votes
1 answer
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Why are my area calculations in Python so small with .area()?

I'm trying to calculate the area of a flood with Python, but the results seem way too small: iceye_breaks = iceye_breaks.to_crs("+proj=cea +lon_0=0 +x_0=0 +y_0=0 +lat_ts=45 +ellps=WGS84 +datum=...
4 votes
1 answer
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Which projection type is most suitable for area calculation of northern hemisphere using arcgis/qgis?

which projection will be most suitable for the area calculation of polygon which is almost covering the whole northern hemisphere? I am trying to calculate the area of the historic distribution of ...
1 vote
1 answer
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Comparing polygon areas across simple feature collections

I currently have three simple feature objects created from different shapefiles in R using the sf package. These three objects have all been projected to the same coordinate system using st_transform()...
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Calculating area of habitat suitability map obtained from Maxent using ArcMap

I am doing a species distribution modelling using Maxent. I got the species distribution maps from maxent and I reclassified the map into four group as high, moderate, low and unsuitable areas in ...
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1 answer
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Dissolve a intersection along id and keep only features of the bigger area QGIS

In QGIS I'm trying to dissolve an intersection and keep only the features with the bigger area [blue arrow] (compared with other features with same id [red box]). I'm interested in keeping other ...
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4 votes
1 answer
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Incorrect ST_Area after changing to 4326 in PostGIS

I'm trying to change the geometry in our database from 3857 to 4326 so that I can use more functionality within PostGIS. It converts them all properly when I run the alter column and transform query: ...
5 votes
2 answers
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Getting "QgsPolygon: CurvePolygon EMPTY" when extracting the largest part of MultiPolygon using PyQGIS

There is a shapefile with MultiPolygons, see the image below With this code, I am trying to get the largest part (by area) of each MultiPolygon feature. It utilizes the constGet() method. layer = ...
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1 vote
1 answer
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Dissolving features based on another layer in QGIS

I have two layers, see image below: Yellow: the ground where people can build; Red: existing buildings. Create a shapefile of all grounds where >50% of the grounds are free. In order to do this, ...
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2 votes
1 answer
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Finding correct ellipsoid to calculate the surface of polygons (hectares) in QGIS

I would like to calculate the surface of a group of polygons in QGIS. It was not me to create the shapefile, when I add it to the project and I check its properties, it results that the geometry and ...
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Calculate cell/pixel area with Rasterio in Python

The Situation I have a tile spanning 10° north-south (n-s) and 10° east-west (e-w), e.g. from 10-20W and 10-20N. This tile contains multiple pixels, e.g. with a resolution of n-s and e-w of 100m at ...
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4 votes
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r.surf.area outputs are unclear (QGIS)

For different projects in my company the area was calculated using $area (and sometimes area($geometry) in the Field Calculator. I decided to change the surface area calculation to using the r.surf....
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How to get a list of the empty areas between the filled ones? (+size in ha)

I am an absolute beginner in GIS software. My goal is to get a list (or something similar) of all the empty polygons/areas between the colored ones. It would be perfect if the size and location of the ...
1 vote
1 answer
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Area based Heatmap (QGIS)

I am new to QGIS. I am trying to create a heat map based on area not points. What I want to acheive is similar to this question. I want to create a binary raster (0 for no point, 1 for point). Then, ...
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How to import CAD drawings into QGIS?

I have a dxf with a polygon. This polygon has an area of 680279.678 m² in Autocad. When i import it into QGIS and calculate the area in the field calculator with area($geometry) i get 680281.25 I ...
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Computing area of very large feature collection in GEE?

I'm trying to calculate the total area of a very large Feature Collection (over 1 million features) of burned areas over the Amazon. I want to find the total area (sum), and also the area grouped by ...
3 votes
2 answers
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Getting area of part of MultiPolygon in QGIS

Is it possible, with QGIS, to get the area of a single part of a multi polygon? Or do I have to split them into single polygons?
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2 answers
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Calculating area with formula gives zero in the attribute table in QGIS

I am trying to calculate the area of each patch of a vector on the total area of all my vectors (sum of each area) with the following "area" / "totalarea" but then it returns 0, ...
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5 votes
1 answer
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Draw buffer around points considering slope in QGIS

I generated random points on a map. Around each point I would like to draw a circular buffer which considers the slope in that area, and within these circular buffers I would monitor tree height in ...
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1 vote
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Calculating area of polygon with consideration of slope in QGIS [duplicate]

I would like to know if there is an easy/efficient way in which you can calculate the area of a polygon considering the irregular slope underneath the polygon. I would like to know a solution in QGIS.
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Do you need to factor in projection into area calculation in Google Earth Engine (GEE)?

I'm interested in calculating the area I have classified of a certain class. Do you need to account for projection to assess class area or can you run the following code and it will be accurate? I'm ...
0 votes
1 answer
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Convert unit of measurement for a buffer area

I have generated buffers around geocoded points on a map. The shape areas for buffers are clearly different than the shape areas generated when projecting polygons (such as tracts, CDPs, or counties). ...
5 votes
1 answer
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Raster classes area calculation

I have 3 raster layers each of them is classified into 4 classes and each one has defined weight value. I had to to create FINAL raster by multiplying those 3 rasters with their weight values and ...

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