Linked Questions
25 questions linked to/from Coordinate system for accurately calculating areas of polygons that cross UTM Zones?
3
votes
0
answers
68
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Projecting polygon when calculating its area using R? [duplicate]
I have a broad range of polygons (in vector format and in SpatialPolygonsDataFrame class), some going east-west, others going south-north, while even others span polar regions or very large ranges as ...
- 65.3k
5
votes
0
answers
487
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Intersection and area calculations in geographic vs. projected coordinates
I think one should do intersection calculations when layers are in the same coordinate system, and one should do area calculations in the appropriate projected coordinate system.
The order matters, ...
- 71
4
votes
2
answers
21k
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What are the units of the calculated area from a raster in decimal degree
I'm trying to calculate area for a raster file which contains 2 layers (0 for unsuitable habitat and 1 for suitable). It's been calculated successfully but I don't know what is the unit of the ...
2
votes
0
answers
495
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How to choose a projection for area measurement on building to continental scales?
I have many geographical objects described as polylines, polygons, multipolygons. All objects are in WGS84. Object could be: a building, stadium, park, street, highway, city, state, even country and ...
- 82.7k
3
votes
1
answer
1k
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PostGIS: calculate area of intersection of EPSG:27700 polygons?
I have two tables in Postgres, both of type geometry(MultiPolygon,27700) and I would like to find any that intersect with an area of more than 100 square metres.
I know how to get any that intersect ...
- 1,197
1
vote
2
answers
1k
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How to calculate the area in kernel density?
I have estimated and reclassify my kernel densities and I would to calculate the area of each value. How could I do it?
My Projected Coordinate System is WGS84 World Mercator. My pixel size is 10000 ...
- 32k
4
votes
1
answer
199
views
Why does not equal length of line in DIRECTION/LENGTH with length of line in MEASURING in OpenLayers 2.13? [duplicate]
My map projection is: "EPSG:900913", display projection is "EPSG:4326" and units is "m", however does not equal the length in Direction/length with the length is calculated in measuring in OpenLayers, ...
- 13.5k
1
vote
1
answer
384
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Getting geodetic area from rgeos::gArea? [closed]
I need to get an area of different polygons at continental scale (like third of Africa etc.). Usual functions like rgeos::gArea work only in the projection units.
Is there any function which works ...
- 65.3k
8
votes
1
answer
8k
views
How to measure areas of features in OpenLayers plugin background maps correctly?
I can't figure out how to make areal calculations (eg. in km2). I have tried the 'field calculator', I have tried the 'measure area' function on the "attributes" toolbar, and i have tried fTools in ...
- 84.4k
1
vote
0
answers
286
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how to calculate area if it is falling in two utm zones [duplicate]
I am using ArcGIS 10.1. How do I calculate an accurate area measure for a polygon, where portions of it are falling in two zones, i.e. UTM ZONE 44 & 45 (India)?
- 65.3k
3
votes
2
answers
762
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How to calculate area in sq m - troubleshooting projection issues in a global dataset in QGIS
I am using QGIS version 2.12.3.
I have 3 polygon shapefiles: A, B and the intersect of A and B, which we can call C.
All I want is to add a field to the attributes table of each shapefile giving ...
- 333
0
votes
1
answer
53
views
calculating ratio of areas on a sphere
I have 2 shapefiles and after identifying their intersections I'd like to know the ratio of intersecting areas, e.g.
a given shape S in file1 intersects with shapes (x1,...,xn) in file2 with ?...
- 49.8k
1
vote
0
answers
98
views
What is the right projection for area calculation in Kenya? [duplicate]
I want to calculate the area of counties (1st admin level) in Kenya in ArcGIS. What is the right projection for that? I know I should use an equal area projection, but when I use them (I tried six ...
- 65.3k
4
votes
2
answers
3k
views
Polygon area calculation in Ruby (on Rails, rgeo, PostGIS and GEOS) in sqare meters
In a Ruby-on-Rails application, I need the area in square meters (or any other surface measure, be it ares, hectares, square kilometers, but not in pseudo surface measure like square degrees) of a ...
- 101
0
votes
1
answer
225
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What is most accurate Spatial reference system for calculate Area entire world [duplicate]
I want to know what Spatial reference system is most accurate to calculate area?
I want to use it for entire world (-180,+180,-90,+90 area in WGS84 system) I have every thing ok I only need to ...
- 65.3k