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Questions tagged [equal-area]

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Why are discrete global grids vs. making a custom grid using a tesselation different in size and shape?

I need an equal area grid system that can vary in area (i.e. 100km2 to thousands). I have two ways of doing this at continental scales (Asia + Europe as an example). One way is to create a tesselation ...
Leo Ohyama's user avatar
0 votes
1 answer
20 views

Calculating area percentages of another vector file based on vector grid using ArcGIS Pro

I have a grid (vector file) in ArcGIS Pro, and I want to calculate the percentages of the area of different anthrome types in the other vector file (Anthromes 12K DGG Dataverse) for each grid cell. I ...
cloudberry's user avatar
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0 answers
97 views

Understanding Equal Earth Projection (EPSG:8857)

I am considering using the Equal Earth Projection (EPSG:8857) in a project because it seems to meet the requirements I am after. If I understand correctly, because this is an equal-area projection ...
cmosig's user avatar
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1 vote
0 answers
47 views

Recenter projection of world map in QGIS [duplicate]

I'm a beginner in QGIS. I would like to use world maps with different longitudes in the centre for my geography lessons. I am trying to create world maps centred on different longitudes (others than ...
Ole Joerss's user avatar
2 votes
1 answer
69 views

Compute the area of differents buildings for differents regions in GeoPandas

I'm really new to GeoPandas so this question may have already been answered (I hope not). I have a GeoPandas dataset with points that represent the coordinates of buildings and I would like to ...
Pierrick Bournez's user avatar
1 vote
1 answer
75 views

Estimating area from global raster datasets

I am trying to estimate how much area of emerged landmasses is covered by each of the 12 great groups of soils defined in the USDA Soil Taxonomy with rasterio/rioxarray. My results differ quite a bit ...
e5k's user avatar
  • 160
1 vote
0 answers
287 views

Dividing a polygon into only two equal areas in QGIS

I would like to look at only 50% of the area. To do this, I would like to divide the surface into two equal areas. (Afterwards, I would like to automate it using the model builder). I have followed ...
miraculix's user avatar
  • 169
2 votes
1 answer
222 views

Split polygon with West East direction with equal area in PostGIS

This code splits into NS direction but I need to split with WE direction (horizontally): WITH foo AS ( SELECT id,name,geom, blade FROM admin4 CROSS JOIN LATERAL ( SELECT ST_xMin(geom) + (ST_xMax(geom) ...
Rabi Gorkhali's user avatar
2 votes
1 answer
334 views

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 ...
axre's user avatar
  • 63
6 votes
0 answers
6k 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, ...
emax's user avatar
  • 269
0 votes
1 answer
76 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 ...
Cora Coleman's user avatar
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0 answers
34 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["...
Rasmus Ø. Pedersen's user avatar
1 vote
0 answers
155 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 ...
AD_R's user avatar
  • 11
2 votes
1 answer
2k 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 ...
meaning piano92's user avatar
4 votes
3 answers
3k 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 ...
Jwely's user avatar
  • 211
4 votes
1 answer
835 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 ...
Hardau's user avatar
  • 101
19 votes
7 answers
22k 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 &...
Kapildev adhikari's user avatar
4 votes
2 answers
2k 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 ...
Khaled's user avatar
  • 287
2 votes
0 answers
196 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 ...
user9322960's user avatar
5 votes
2 answers
1k 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 ...
user9322960's user avatar
3 votes
1 answer
446 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"...
radouxju's user avatar
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5 votes
3 answers
2k views

Splitting circle polygon into equal sectors in QGIS

How do you split a circle polygon into equal sectors that are 5 degrees in width in QGIS? I have a shapefile from a boundary of a field and want to break it into sectors.
Chad Godsey's user avatar
1 vote
1 answer
148 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" ...
dbaston's user avatar
  • 13.1k
0 votes
0 answers
73 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
Tobias_Terra's user avatar
0 votes
1 answer
67 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 ...
johnsankey's user avatar
8 votes
1 answer
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) ...
Sylvain C.'s user avatar