Questions tagged [equal-area]
The equal-area tag has no usage guidance.
23
questions
0
votes
0
answers
50
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 ...
- 143
1
vote
0
answers
42
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 ...
- 11
2
votes
1
answer
45
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 ...
1
vote
1
answer
47
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 ...
- 150
1
vote
0
answers
221
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 ...
- 169
2
votes
1
answer
194
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) ...
1
vote
1
answer
280
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 ...
- 53
6
votes
0
answers
5k
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, ...
- 269
0
votes
1
answer
73
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 ...
0
votes
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["...
1
vote
0
answers
141
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 ...
- 11
2
votes
1
answer
1k
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 ...
2
votes
1
answer
2k
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
...
- 181
4
votes
1
answer
784
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 ...
- 101
19
votes
7
answers
19k
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
votes
2
answers
1k
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 ...
- 335
2
votes
0
answers
155
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 ...
- 343
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 ...
- 343
3
votes
1
answer
393
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"...
- 49.4k
1
vote
1
answer
134
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" ...
- 13k
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
- 31
0
votes
1
answer
65
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 ...
- 573
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) ...
- 193