29
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....
22
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 ...
17
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, ...
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 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'...
13
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 ...
13
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 ...
12
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, ...
11
ArcMap just orders based on geometry type: 1. Points, 2. Lines, 3. Polygons.
My suggestion is to use transparency to help you symbolize these overlapping features. Take a look at a color wheel when you're selecting colors and choose colors that have good additive properties.
By using this technique you'll be able to identify the individual layers and ...
11
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.
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....
11
You can use the 'Check Geometries' plugin (Vector/Geometry Tools/Check Geometries) to remove overlapping areas.
10
Few options. Some crazier :-) than others. The basic strategies are
Cluster features
Hide/move the top feature
Send the click through the top feature
==>
Turn on feature clustering strategy
Implement your own clustering algorithm, so when a new item is added or modified, your algorithm re-runs and does a nested for-loop check and n*n(-1) checks to see ...
10
I have not used ArcGIS Schematics for more than some quick demos quite a few years ago, but there is a blog posting on Create route maps with the ArcGIS Schematics extension that may provide a solution.
10
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 ...
10
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
...
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 custom Count Overlapping Polygons tool.
Description:
This sample contains a toolbox with one tool, Count Overlapping
Polygons. Given a feature class or layer containing overlapping
polygons, outputs a new feature class with the overlaps removed and a
Join_Count field containing the number of overlapping polygons.
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
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)
8
ST_Intersection(geomA, geomB) returns a geometry, then calculate areas with ST_Area.
8
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 ...
8
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
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 ...
7
the quick and dirty method consists in using the "union" tool with the layer alone. Two new polygons will be created where polygons are overlapping and you can remove one of them. This is not straightforward but you can use "find identical" to get the polygons to be deleted.
The more advanced solution consists in building a topology for your layer (with ...
7
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.
7
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 ...
7
You will need:
1) A table with LineString geometries:
CREATE TABLE lin (
id serial PRIMARY KEY,
geom geometry(LineString, 31370)
);
CREATE INDEX ON lin (id);
CREATE INDEX ON lin USING gist (geom);
2) A table with Point geometries where you want to split your overlapping lines. They can represent train/metro stations, intersections, bifurcations etc.
(...
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