Can a polygon have overlapping sides?
Polygons may not have sides that overlap. Some say that these shapes are still polygons, known as self-intersecting or crossed polygons, but most properties of polygons do not apply to these, so they are best considered as two separate polygons.
Can polygons be squares?
In non-Euclidean geometry, squares are more generally polygons with 4 equal sides and equal angles. In spherical geometry, a square is a polygon whose edges are great circle arcs of equal distance, which meet at equal angles.
How to calculate the overlapping parts of a pair of shapes in PostGIS?
So an overlapping set of three circles becomes a non-overlapping set of 7 polygons. Calculating the overlapping parts of a pair of shapes is easy, using the ST_Intersection () function in PostGIS, but that only works for pairs, and doesn’t capture the areas that have no overlaps at all.
How to measure polygon overlap in QGIS coordinates?
Multiplying by this fraction gives us square miles (or if you prefer, divide by 1000000 to get square kilometers). It’s important that we set the field type to a real / decimal number and specify a meaningful length (total number of digits) and precision (number of digits right of the decimal place).
How to reproject polygons in PostGIS and QGIS?
To reproject them, we select each one in the layers panel, right click, and choose save as. Browse and save them as new files, hit the CRS button, search for North America Albers Equal Area (AEA), select it, and save the new layers in that system.
Can you turn a collection of overlapping polygons into a non-overlapping set?
What they mean is, “can you turn a collection of overlapping polygons into a collection of non-overlapping polygons that retain information about the overlapping polygons that formed them?” So an overlapping set of three circles becomes a non-overlapping set of 7 polygons.