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Questions tagged [graph]

A graph is a representation of a set of objects where some pairs of the objects are connected by link

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2answers
51 views

Networks plugin missing from QGIS 3.4.7?

I installed the Networks plugin in QGIS 3.4.7 successfully, but it does not appear in the Vector Tab. Can anyone suggest another way to reverse the direction of a vector used in a network (graph)?
3
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1answer
67 views

How to create a virtual layer in QGIS that shows only the features in the extent

I am trying to make a virtual layer that is based on a map layer that only returns the features in the current map canvas extent. The purpose is to setup a Data Graph that shows statistical data of ...
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0answers
11 views

Get visible polygon form one point (visibility graph with one point)

Problem I would like to get the visibility of one point in regard to a polygon layer. E.g. which island can I see from the beach. What I found It's possible to get a visibility graph via Grass v....
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1answer
39 views

PyQGIS3 retrieving points from a shortestpath graph

I'm upgrading some code which worked with QGIS 2.18 to now work with QGIS 3.4.5 and had the following snippet working to retrieve a set of points from a graph created by the QgsGraphBuilder function: ...
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1answer
71 views

Constructing a graph from a city in Python using Overpass

I'm looking to construct something exactly like this person Building a graph from OSM? That is I need to construct a graph with intersections as nodes and roads as edges for a simulation. Unlike this ...
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0answers
27 views

Complex edge conditions on geo-edges

Spatial graph databases are capable to find a shortest path from the node A to the node B. Are there any DB which allows complex conditions on nodes and edges between them? For example: The node is ...
2
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0answers
105 views

How to build a route that traverses every edge at least once and begins and ends at the same location?

I have a collection of lines in PostgreSQL w/PostGIS/pgRouting and have built topology. I need to produce a route that starts and ends at the same location, but traverses all of the edges. Can ...
2
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1answer
50 views

Building Graph in QGIS for Service Area computing

I do have a vector shapefile with a streets network a point shapefile with 5 supermarkets as points Everything is right now in WGS 84. I would like to perform QNEAT's "ISO AREA AS POLYGON from ...
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2answers
97 views

Clean road network from nodes blobs

I have a graph representing a road network and I need to clean it before working on it. Problem is that the original shapefile is not clean so when I make the graph I have many useless nodes too close ...
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0answers
223 views

Drawing graph elements (nodes and edges) in Leaflet?

I need to build a simple online map editor and I'm intended to use leaflet (but can eventually use openlayers). How can I draw graph elements (nodes and edges) in leaflet (on top of a map). ...
2
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1answer
2k views

Road graph plugin in QGIS 3.2.2

Where can the Road Graph plugin be found in QGIS 3.2.2? It is not among the plugins.
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0answers
235 views

Networkx shortest paths for two point layers

I have a task to know the best way from houses to subway station. There are three types of data on a picture below: orange dots are the entrances to subway stations violet dots are centerspoints of ...
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0answers
24 views

Adding location points to a graph of roads using osmium and finding the closest roads

I am using c++ 11 and libosmium 2.13.1. In my project I need a graph of roads of an area and I I have figured that part out. My problem is with adding locations to that graph that are not located on ...
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0answers
332 views

Creating histogram for continuous raster dataset in Create Graphs wizard of ArcGIS Desktop?

I would like to create some histograms of continuous raster data (in TIFF format) to display in a report. When I enter the Create Graphs wizard, I can only display histograms for feature classes, not ...
1
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1answer
210 views

Most efficient way to check graph edge or node overlap with circle border on euclidean plane (2D space)

Suppose that there is a given graph, in terms of nodes with specific placement on the euclidean plane (2d space) (for ex. node A is at (7,14) 7 is x-axis and 14 is y-axis) and edges that specify which ...
1
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1answer
100 views

Creating frequency graph in layout view of ArcGIS for Desktop using Quantile symbology?

I'm interested in creating a graph showing the frequency of my data based on the categories of my Quantiles symbology. The Graphs Manager does not seem to allow me to do that, so I was wondering if ...
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2answers
89 views

Building graph from database structure to implement A* algorithm?

I imported an osm file into a postgresql database using osm2pgsql. Now, I want to implement a route/path generating algorithm (routing algo) based on two locations entered by a user. It is not ...
2
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1answer
171 views

Merging multilane road into one lane

I have a road network file (openstreetmap exported file) that has various types of edges (freeway, highway, primary, residential, service, ...). Some of these edges have multiple lanes (parallel), so ...
1
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1answer
261 views

The Filter geometry function in T-SQL is not precise and does not return valid results

I have two tables, edges (a set of polyline features): and nodes (set of points): I want to find the "id" of those points that have an intersection with the first point of any edges. I used the ...
2
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0answers
380 views

How can I transform OSM road data to a graph network in 2018? [duplicate]

I see a lot of questions in this topic, but most answers are at least 4-5 years old. I wonder if there is a more current solution that would allow me to gain a graph network from the OSM highways data....
4
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1answer
430 views

commuteDistance in gdistance package in R giving error

I am currently trying to run a function that "calculates the expected random-walk commute time between nodes in a graph. It is defined as the effective distance (resistance distance) between the ...
3
votes
1answer
300 views

How can I calculate averaged response curves for Maxent models fitted using maxnet package in R?

Could someone please point me towards an efficient approach? plot and response.plot (maxnet package) can produce response curves for individual models, but feeding a list of model replicates, as ...
1
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1answer
297 views

PostGIS - Tracing topological network

I am tracing the Postgis topological network with Postgresql via: WITH RECURSIVE path AS ( SELECT edge_id,start_node, end_node FROM simulation.edge_data WHERE start_node = 1 OR end_node = 1 OR ...
1
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1answer
142 views

Using pie chart as circular buffer in ArcMap?

I have several circular buffers throughout a map I have made. Each buffer corresponds to a survey site, but differ in size from 15 ft, 10ft, all the way down to 3ft. I was hoping to make a simple ...
0
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1answer
121 views

Automating calculation of cumulative elevation for multiple line segments (not the profile graph)

I'm using ArcGIS and am trying to figure out how to calculate the cumulative elevation gain (in feet or meters) for over 1,000 line segments representing separate, often unconnected trails. I have a ...
3
votes
1answer
780 views

Programmatically infer start and end points from a Polygon with linear characteristics

Question: Given a Polygon exhibiting linear-like qualities (long and thin, with clear extremities upon visual inspection), is there a reasonable/defensible order of operations to compute "start" and "...
2
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2answers
412 views

Shortest path between cities without duplicate calculation (many-to-many)

I have three tables ==> ways, nodes and cities (OpenStreetMap) ways : Edges with required attributes for routing (source, target, cost, etc.) nodes : Each and every nodes linking the edges cities : ...
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0answers
125 views

visualisation of asymmetric Directed acyclic graph [closed]

I have got a data set, it represents the time take taken to get between different nodes on a graph, I have a valid X/Y pair for each node location. The cost of getting between each node is asymmetric,...
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0answers
233 views

QGIS Graph Nonetype using Dijkstra's

I am currently using the Dijkstra's algorithm to find the shortest path between multiple latitudes and longitudes on QGIS. Most of my code is from the Dijkstra's documentation here: http://docs.qgis....
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0answers
68 views

Forcing driving direction using edited OSM shapefile and pgRouting

I need to edit a shapefile from OSM in QGIS. I want to use pgRouting to find a route, where it uses a forced driving direction. The algorithm may use the same edge however to calculate the route ...
1
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0answers
366 views

GIS data visualization

I have a huge data set with geolocation information. I am trying to visualize the data but the tools cannot handle such a big graph. Size of the file is about 5GB and has more than 3 million rows. ...
1
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2answers
1k views

How to convert a shapefile into a graph in which use Dijkstra

I am working in a simulation using NetLogo, the idea is to make the agents interact inside the roads of a simplified city, in order to do that I need to use some algorithms to find the fastest path ...
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2answers
320 views

Moving chart to top of pop-up window in ArcGIS Online?

Is it possible to move a chart/graph to the top of the pop-up window in ArcGIS Online via its GUI? I have numerous fields to display and it works best if the chart is displayed first. Just the ...
3
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0answers
75 views

In MySQL are there unidirectional and directional graphs?

I'm new to MySQL and studying about geospatial data. I have read the documentation of MySQL and learned about the ST_Geometry type, its subtypes and its functions; but I didn't find anything about ...
3
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0answers
68 views

Constructing contiguous regions with similar properties by graph partitioning

I have census data for census output areas. Each area is a geographical region. I would like to partition these areas into contiguous super-regions with similar properties. For example, in each area ...
0
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1answer
53 views

ArcMap Elevation Graph Min/Max Values

I'm trying to create elevation graphs from a set of line features and raster elevation file, while the Stack Profile tool from ArcMap can do that, I need to modify the min/max values of the y-axis to ...
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0answers
521 views

NetworkX or Shapely to get the simplified graph between 2 Graphs?

I'm having trouble whether which approach to take in simplifying a graph from another graph. It's not a basic graph difference but the other way around. I want to further simplify a graph of a street ...
2
votes
1answer
553 views

Making graph from network vector in QGIS?

I have a network of roads and I would like to obtain a graph made by edges, each of them delimited by a origin node and a end node, such as the picture shows. I would like to obtain a table made of ...
1
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0answers
156 views

Is it possible to create a ternary (triangular) graph template in ArcGIS 10.3?

Is is possible to edit a .tee graphing template file to create a ternary diagram (example can be found at http://csmres.jmu.edu/geollab/Fichter/SedRx/readternary.html)? I'm aware of the clever method ...
3
votes
1answer
2k views

How to calculate edge length in Networkx

I want to export a directed weighted graph from a shapefile. I used read_shp function of the Networkx package to export the directed graph which perfectly matches my needs. But I am unable to ...
2
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0answers
318 views

Getting bar chart with negative values to display in ArcGIS for Desktop? [closed]

Using ArcMap 10.4 I'm trying to display bar charts to represent the changes that occurred at several locations. At one point, the change was always negative, and so are the three values (-3; -1; -4). ...
0
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1answer
84 views

ArcGIS 10.2.2 Chart Graph data precision shown

I created a pie chart that had several pieces of data; pipe diameter to length of pipe per diameter. I summarized data from length of pipe and diameter from a database and input into a summary data ...
0
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1answer
77 views

Plotting graphs showing precipitation of area on map?

I have precipitation data of an area and I need to create a bar graph or something on the map of the area showing the precipitation. Is there a way I can do it?? I am a beginner so I really don't have ...
3
votes
1answer
2k views

Understanding Contraction Hierarchies

I'm very interested by understanding how Contraction Hierarchies algorithm works. I have found this page : https://www.mjt.me.uk/posts/contraction-hierarchies/ and read a lot of stuff. I understood ...
0
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1answer
52 views

Constructing distribution graphs of attribute tables using ArcGIS field calculator?

Since I'm new to python I have an issue with writing the correct code to achieve the following. The picture is an example of an attribute table of which i want to make frequency distribution graphs ...
0
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1answer
509 views

PSO for solving shortest path in matlab

I crate a file that represents 16000 edges with information of start node, end node and cost in a table. In MATLAB i want to solve shortest path with PSO algorithm. How i can solve it?
2
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2answers
1k views

Create time series graph with multiple rasters

I need to create a time series graph for a few random cells with known underlying attribute such as "forest" or "agriculture" based on the VCI (Vegetation Condition Index). I have been reading and ...
1
vote
1answer
249 views

Constructing a weighted graph a.k.a. a road network with distances for a specific area

Pardon my ignorance in GIS/Routing tools as I'm new to it: I have a map in OSM format and wanted to build a routable graph out of it ( to experiment a searching algorithm I have in my PhD thesis). ...
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0answers
79 views

edge Data labelling OSM local tile server

i have OSM tile server running locally on my machine I have used Leaflet to add markers Now I am looking for graph script in which markers to act as nodes and polygon (more precisely an arc) to show ...
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0answers
130 views

Qgis network prepare road graph

I have been working on finding shortest path between two buildings. For that purpose i have created kml files of various streets, converted them into shape files and then merged all of them together. ...