30
The radius measurements surely are subject to some error. I would expect the amount of error to be proportional to the radii themselves. Let us assume the measurements are otherwise unbiased. A reasonable solution then uses weighted nonlinear least squares fitting, with weights inversely proportional to the squared radii.
This is standard stuff available ...
29
You can do it in QGIS using symbol transparency, feature blending mode and symbol color.
Notice the difference between Layer Transparency and blending mode(that will be applied to all features) and the symbol transparency and feature blending mode that will stack with other features in the same layer.
All seetings are available in Layers Properties > Style....
23
Do this in three steps: break the polygons into their component parts, count the overlaps, and convert to raster. This avoids the potentially huge computational cost of separately converting every polygon to a raster and combining those rasters.
Union (in the Geoprocessing menu) breaks the polygons into their parts.
Unfortunately, each overlap is ...
21
To remove duplicates:
You can use the Delete duplicate geometries tool by accessing it via the Processing Toolbox:
Another option is to use the v.clean tool from GRASS and select the rmdupl option:
To remove overlaps:
You can use the Dissolve tool, provided there are common attributes between the original polygon and the overlapping polygon:
As always, ...
16
Enable Topology Checker Plugin in Plugin Manager. Add your polygonal layer in Topology Rule Settings window, select "must not overlap" rule and add them. To see overlap errors click on Validate button.
14
In ArcGIS, the easiest way to create a polygon layer with the count of overlapping features is as follows:
Run the Union tool on your source polygon layers. This will result in a layer with one feature for each area of overlap.
Add a new field to the layer created in Step 1, called NewID or something to that effect, and use Field Calculator to set it ...
14
This is a graph coloring problem.
Recall that a graph coloring is an assignment of a color to the vertices of a graph in such a way that no two vertices which share an edge will also have the same color. Specifically, the (abstract) vertices of the graph are the polygons. Two vertices are connected with an (undirected) edge whenever they intersect (as ...
14
This is a really nice application for a PostgreSQL trigger. To set up a trigger in PostgreSQL, you do two things:
Create a user-defined function that is run whenever a trigger is called (can be a row insert, update, or delete)
Use a CREATE TRIGGER statement to bind that function to a particular table for a particular operation (in this case, INSERT).
Here'...
14
I recommend that you try using the Intersect (Analysis) tool with one input.
According to How Intersect works (with my bolding):
Intersect can run with a single input. In this case, instead of
discovering intersections between the features from the different
feature classes or layers, it will discover the intersections between
features within the ...
14
A self-join allows you to operate on the relationship between pairs of two features. But I don't think you're interested in pairs: for each feature, you want to operate on the relationship between that feature and all other features in your dataset. You can accomplish this with a subquery expression:
CREATE TABLE parcels_trimmed AS
SELECT id, ...
13
In the situation where you only need to know whether a table contains any overlapping polygons, and you're not concerned with the size or abundance of overlaps, I recommend a query of the following form:
SELECT *
FROM my_table a
INNER JOIN my_table b ON
(a.geom && b.geom AND ST_Relate(a.geom, b.geom, '2********'))
WHERE a.ctid != b.ctid
LIMIT 1
...
12
You can use the 'Check Geometries' plugin (Vector/Geometry Tools/Check Geometries) to remove overlapping areas.
12
The GeoDataFrame
import geopandas as gpd
g1 = gpd.GeoDataFrame.from_file("poly_intersect.shp")
g1.shape
(4, 3)
1) You can use the itertools module
a) If you want to merge the intersections of the overlapping polygons
import itertools
geoms = g1['geometry'].tolist()
intersection_iter = gpd.GeoDataFrame(gpd.GeoSeries([poly[0].intersection(poly[1]) for poly ...
11
areas = []
for line_feature in line_layer.getFeatures():
cands = area_layer.getFeatures(QgsFeatureRequest().setFilterRect(line_feature.geometry().boundingBox()))
for area_feature in cands:
if line_feature.geometry().intersects(area_feature.geometry()):
areas.append(area_feature.id())
area_layer.select(areas)
11
One way of doing this is cloning the layer, using definition queries and labelling them separately, using upper-left only label position for the first layer and lower-left for second.
Add THEFIELD type integer to layer and populate it using expression below:
aList=[]
def FirstOrOthers(shp):
global aList
key='%s%s' %(round(shp.firstPoint.X,3),round(shp....
10
It is very complicated task known as bin packing problem.
The script below produces one of countless sub-optimal solutions. Algorithm:
places fish net over rotated POLYGON to find out rotation angle in range (0,175,5) that result in maximum count of complete rectangles
breaks if no such rectangles found, otherwise
un-rotate every good rectangle and append ...
10
Try Point displacement or Point cluster from symbology menu. (QGIS 3.x required for point cluster.)
As point displacement they can look like this for example:
And as point cluster like this for example:
Play around with the settings to fit your needs. You can combine these with graduated, categorized or rule based renderer; Set up own styles and adjust ...
9
You can use "cartograpic representations" to display your points. Then use the Disperse Markers tool. Your point coordinates will still the same, only the position of the symbol (=representation) will move.
This requires a ArcInfo license (ArcGIS for Desktop Advanced).
9
I would recommend using the Count Overlapping Features (Analysis) tool.
Generates planarized overlapping features from the input features. The
count of overlapping features is written to the output features.
9
This can be easily accomplished using PostGIS. Preview the results using a modified version of the query below:
SELECT a.id, b.id, ST_Area(a.shape), ST_Area(b.shape)
, 100*(ST_Area(ST_Intersection(a.shape, b.shape))/LEAST(ST_Area(a.shape), ST_Area(b.shape)))::numeric(5,2)
as pct_overlap
, ST_Union(a.shape, b.shape) as new_shape
FROM ...
9
You can do this with 2 tools, Feature to Polygon and Spatial Join
First, run your polygons through Feature to Polygon. Delete any of the attributes you don't need from the output (I still got them even when I turned preserve attributes off):
Then, run Spatial Join:
The target features are the output of Feature to Polygon
The join features are your ...
8
You can use Schematics - The ArcGIS Schematics extension provides a sophisticated data model and a comprehensive set of tools for creating, managing, analyzing, and displaying complex networks. Perhaps less well known is the fact that it contains tools to create custom schematic layouts. You can use ArcGIS Schematics to create maps for any linear network ...
8
The quickest way that I am aware of, is to use the Shapely library (requires the GEOS Engine, you can find a one-click installer for shapely here if you're on windows)
The manual provides a dead-on example of what your question:
>>> from shapely.geometry import Point
>>> a = Point(1, 1).buffer(1.5)
>>> b = Point(2, 1).buffer(1....
8
ST_Intersection(geomA, geomB) returns a geometry, then calculate areas with ST_Area.
8
If your polygons are slivers the eliminate command works well to merge them into either the larger area polygon or the longest edge.
If the polygons are overlaps then there may be an easier way, but I would select out the overlaps to a separate layer, then union them back in, creating the slivers and using the eliminate command.
8
JSFiddle Example
I've created a JSFiddle demonstrating a solution to your problem using the JavaScript Topology Suite (JSTS) (JSTS) library.
Explaination
There are two steps to this approach. The first step converts your Google geometries into WellKnownText (WKT) geometry expressions, which is a widely supported format. The second step uses JSTS to ...
8
QGIS Processing Toolbox has a SAGA Polygon self-intersection tool (under SAGA | Vector polygon tools).
It works much like QIGS Union Tool, while this tool retains only one feature per the overlapped area.
Open the attribute table of generated Intersection layer and select Delete all features whose fid (or id) is 0.
8
I use the 'Line Pattern Fill' with a different colour and line fill rotation for each layer.
It can be useful to create a variable in the project properties to use as the spacing between lines, fill line weight etc, this will make it easier to adjust all layers by changing one or two variables instead of lots of variables for different layers.
See below ...
7
The Generate Conditional Random Points tool from Geospatial Modelling Environment should do the job for you. If you specify the BVUNIFORM option for the distrib atttribute (distribution) you can supply a radius around the input points within which new points will be generated in a uniform distribution. The number of points generated (the sample attribute) ...
7
You can use an offset for one of the two routes. You find the option for each line style.
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