Questions tagged [equal-area]

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Calculate area for Chinese cities

The task is to calculate areas for small project sites (polygons) in various Chinese cities. The dataset is available as EPSG:4490, the project CRS is also set to EPSG:4490. To get accurate comparable ...
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0answers
31 views

Seeking WMTS service using equal area projection

When looking at campaigning sites, I have been struck that the use of Google maps (because it is easy and works) and therefore the use of epsg:3857 gives undue political impact to certain countries. ...
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0answers
428 views

Splitting polygon into equal area polygons using shapely

I would like to split complex geometries into n smallest geometries of the same area in Python. While I can divide simple geometry in the following way: from shapely.geometry import LineString, ...
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1answer
29 views

Calculating total area of pie charts in ArcMap

Background: I am scaling the size of pie charts by a field which indicates a percentage. I am doing this for two datasets displayed on two maps and would like the resulting areas of the scaled pies to ...
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0answers
22 views

ArcGIS treats two similar projections definition differently

I am about to recreate a global grid in ArcMAP, based on the Behrmann projection I though. The map I want to recreate has this definition (in the .prj file): PROJCS["...
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0answers
59 views

Calculate total area of both adjacent and contiguous raster cells within a radial distance around a polygon's centroid

I have a raster containing grid-cell values of either 1 or no data, NA, representing used- or unused-habitat types, respectively. Using R's raster package, I want to calculate the total area (in ...
2
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1answer
526 views

Appropriate equal-area cylindrical projection for Southeast Asia?

Background I am facing difficulty in selecting an appropriate equal-area map projection suitable for the geographical extent of Southeast Asia. The main resource I am consulting is Savric et al's ...
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1answer
611 views

EPSG codes for projections to use when computing the area of global polygon sets in python env

The general answer to this question is "Use any equal area projection in units of meters that covers the world". Python code needed to make use of this is short and sweet: import geopandas as gpd ...
4
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1answer
517 views

Dividing polygons into equal parts by the number of points inside

I would like to divide many polygons into 2, 3 or 4 parts. I have vectorized plants. Sometimes 2, 3 or more plants hide under one polygon. Depending on the size I just have to divide the polygon into ...
18
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7answers
8k views

Splitting polygon into equal area polygons using QGIS

There is a Plugin in QGIS 2.18 called "Polygon Divider" which divides an irregular polygon into smaller equal-area polygons of a specified/custom-sized but in QGIS 3.x version there is no &...
3
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1answer
800 views

Calculate area of ellipsoidal polygon with QGIS

There is online service of GeographicLib, by Karney, where one can calculate the area of ellipsoidal polygon without need of reprojection. Can one calculate the area of geometry in QGIS so as ...
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0answers
71 views

Accurate area calculation for countries worldwide individually [closed]

I have polygons of countries with its administrative divisions, I would calculate the areas of each division in a country accurately. I got the bounding boxes for each country, then I divided its ...
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2answers
702 views

Geometric difference between equal-area and conformal projection

For simplification, let's have a source light for a map projection. I know where to put the source light in order to get an orthographic, stereographic, gnomonic map projection, but I still don't ...
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1answer
181 views

Equal area projection of Antarctica ?

I was looking for an equal area projection of Antarctica, but it seems that the Lambert Azimuthal Equal Area (https://epsg.io/3974 , also called 102020 by ESRI) is deprecated because it is not a "true"...
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1answer
97 views

How can I use the Eckert IV projection with GeoServer WMS?

I'm trying to request a map in the Eckert IV using a WMS hosted by GeoServer. When I set srs=EPSG:54012 in my query string, I just get a sad XML response: <?xml version="1.0" encoding="UTF-8" ...
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0answers
68 views

Equal area projection

In which projection I should project a polygon of a country to get the right area in the attribute table without a distortion? For example greenland
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1answer
60 views

problem converting OTF from Mercator to equal area

QGIS 1.8.0 on OSX 10.10.5: I've got continent outlines from Natural Earth that are in EPSG:4326 (degrees) plus USGS tree range data in EPSG:2030 (also degrees). When I set the project CRS to EPSG:4326 ...
8
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1answer
1k views

Equal area projections with different area results in ArcMap? [closed]

Using ArcGIS, I have to calculate areas of huge polygons all over the Pacific Oceans betwwen 20N and 30S. I have been trying different Equal-areas projections (Cylindrical and sinusoidal for example) ...