All Questions
65
questions
1
vote
1
answer
46
views
Calculate ratio of 2 polygons using QGIS modeler
Working with QGIS modeler, I need to do some arithmetic operations with some polygon areas.
Let's say there are 2 polygons in layer A and layer B. And I'm inputting them into the model using Vector ...
- 123
1
vote
0
answers
83
views
QGIS ellipsoidal area values changing very slightly between calculations while planimetric values stay the same
I have a number of vector shapefiles that I need to calculate the geodesic/ellipsoidal area for. These shapefiles are accessed and updated regularly, with the area recalculated each time they are ...
- 57
1
vote
2
answers
66
views
QGIS Count values between two numbers inside a polygon in another layer
I have 2 layers.
LayerA are multiple polygons of the area that i'm evaluating (Red boundarys).
LayerB is a MSAVI raster to vector with the data (multicolor greens - blues).
I want to calculate the ...
- 87
0
votes
1
answer
74
views
Adaptive polygon division in QGIS
Let say I have an irregular polygon layer that I want to divide into squares of fixed size (i.e. 50 x 50m). The simplest solution is to create a grid based on the polygon extension and then use the ...
- 47
4
votes
1
answer
94
views
Add polygon areas by roof orientation condition
I have a shapefile with building poligons and a raster file with the roof orientation (0-360º). I would like to assign the orientation to the building shapefile using QGIS. I converted the raster file ...
- 309
4
votes
1
answer
169
views
Why area of intersection differs from total area of polygon?
I calculated intersection between Layer 1 and Layer 2 using expression below:
area(
intersection (
$geometry,
collect_geometries(
overlay_intersects ('layer1',$...
- 155
2
votes
1
answer
74
views
Merging all polygons (and their respective attributes) into similar areas in QGIS
As you can see in the image, I'm trying to merge selected polygons and their respective attributes. I have thousands of these polygons (some very small, others very large). I have to create areas of ...
- 21
3
votes
1
answer
140
views
Create competing polygons from points and bearings (azimuth)
I have a set of points on a city, representing CELL TOWER locations. Each CELL TOWER has 3 or 4 different CELL RADIOS pointing to diferent directions (Azimuth). What I need is an algorithm to take ...
0
votes
1
answer
686
views
QGIS calculate area automatically
Is there a way to calculate area automatically when I edit a polygon? I mean, is there any function there I can use on area field and update itself when I finish editing?
- 671
3
votes
2
answers
268
views
Calculate the percentage of a polygon either side of a line
I have a series of polygons outlining distributions of various fish species around Australia. I am relatively new to GIS.
I am trying to class each species as either tropical or temperate based on the ...
- 41
1
vote
1
answer
103
views
Calculating area's region in DEM
I have a DEM map in my project Tsunami Assesment project.The white area below the mentioned map is sea and we know that possible tsunami height is 14 meters(please neglect the line, there is an error ...
2
votes
1
answer
204
views
Calculating cumulative sum of area values in attribute table by graphics in QGIS
In QGIS I have a set of polygons divided into plots, each polygon has a diameter and area. I would like to sum up the polygons per each plot area.
From the attribute table, the polygons are not ...
- 69
0
votes
1
answer
150
views
How to get a list of the empty areas between the filled ones? (+size in ha)
I am an absolute beginner in GIS software.
My goal is to get a list (or something similar) of all the empty polygons/areas between the colored ones. It would be perfect if the size and location of the ...
- 140
1
vote
0
answers
73
views
Calculating area of polygon with consideration of slope in QGIS [duplicate]
I would like to know if there is an easy/efficient way in which you can calculate the area of a polygon considering the irregular slope underneath the polygon. I would like to know a solution in QGIS.
- 615
3
votes
1
answer
550
views
QGIS 3.8.3 - Create polygon with a specific width
I'm very new to GIS and QGIS.
I'm trying to map areas of arable fields and would like to create a polygon that traces the edge of a field and is a specific width away from the edge of the field ie 8 ...
- 33