Linked Questions

5 votes
0 answers
474 views

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, ...
JPC's user avatar
  • 71
3 votes
1 answer
1k views

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 ...
Richard's user avatar
  • 3,299
1 vote
2 answers
1k views

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 ...
Sofia Margaroni's user avatar
1 vote
0 answers
285 views

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)?
Kundan's user avatar
  • 11
3 votes
2 answers
748 views

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 ...
ElephantTwelve's user avatar
0 votes
1 answer
51 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 ?...
Anna Magdalena's user avatar
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 ...
Enzo Baldini's user avatar
  • 2,347
0 votes
1 answer
220 views

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 ...
Majid Hojati's user avatar
4 votes
1 answer
197 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, ...
Samane's user avatar
  • 989
1 vote
1 answer
148 views

Choosing projection for calculating 2D 3D area in New Zealand?

I'm trying to use Surface Volume tool in ArcMap to calculate 2D and 3D area of a catchment. What would be the best projection to use and how do i check the maximum error of the estimation?
Jiajia Liu's user avatar
11 votes
2 answers
740 views

Why do I get correct area and intersect area when use wrong projection?

I need to calculate areas and intersection areas for polygons (some real geographical objects like lake, city, country, e.t.c.). Polygons located in California, New Zealand, Russia.Anadyr, Sweden All ...
Capacytron's user avatar
1 vote
1 answer
383 views

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 ...
Tomas's user avatar
  • 1,252
2 votes
0 answers
494 views

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 ...
Capacytron's user avatar
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 ...
das-g's user avatar
  • 1,465
1 vote
0 answers
3k views

Why Haversine formula and Web Mercator give different length between two latlng points?

I am calculating the distance between two points given by latlng. However, Google Maps (i.e., web mercator projection) gives me a longer distance than Haversine formula. Which is the most accurate ...
pedromateo's user avatar

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