Questions tagged [connectivity-analysis]

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7
votes
1answer
201 views

Clustering points and summing up attributes per cluster in QGIS

We want to find out the ideal location for sheds and the required dimensions of each shed. As input, we have a point layer with locations (each representing one arable field) and the estimated yield ...
0
votes
1answer
38 views

Calculating connectivity of region?

I have some regions that I have defined and all the public transit in the State, shown here: The blue blobs are the regions, points are the bus/tram stops, and the lines are the routes. I want to ...
1
vote
0answers
27 views

How to fix transportation network connectivity problem? [closed]

I am using network analysis in ArcGIS to conduct a health-related analysis of limited resource country. the quality of the road network layer is not high, with many connectivity problems between the ...
6
votes
2answers
427 views

Selecting connected lines between start and end point in QGIS?

Is there a method in QGIS to select all connected lines that are between a start and end feature (point or selected lines)? I imagine a workflow going something like this: Choose the starting line ...
7
votes
0answers
194 views

How do I select the longest connected lines from PostGIS ST_ApproximateMedialAxis?

I used PostGIS ST_ApproximateMedialAxis to transform polygons representing mountain ranges into a series of lines. Now, I'd like to select only the "longest" line segment for each group, so that I ...
0
votes
1answer
81 views

Filtering out clusters of features based on collective area threshold using QGIS/python?

I have a map I generated that roughly estimates timber industry land ownership (designated by the green on the map) in the counties surrounding the Salish Sea in the US state of Washington: I want to ...
1
vote
0answers
209 views

Fish passage connectivity analysis using geometric network traces?

We are looking at the connectivity between lakes and the ability of fish to pass between them, considering that downstream presents no barriers for these fish but swimming upstream does (barriers = ...
2
votes
2answers
392 views

The average distance between the roads

I have two vector layers. Roads Line layer Roads Point layer I want somehow to get the average value of the distance between each roads and get average value for my region. Each road has its own ...
2
votes
1answer
254 views

Algorithm for Cost Connectivity tool of ArcGIS Spatial Analyst?

For the Cost Connectivity tool in the Spatial Analyst toolbox, what is the algorithm used to compute the minimum spanning tree? The ArcGIS website includes a general description of how the cost ...
0
votes
2answers
251 views

Using ArcPy to find connected features and update attribute table?

I have a map containing Polylines. There are some blank field names. I want to fill them with the name of connected features. How to use python to find the connected features and update the attribute ...
3
votes
0answers
68 views

Examining each connected pixel to select its neighbors to separate clusters using ArcGIS for Desktop? [duplicate]

I am trying to develop a methodology for separating pixels from one another to determine whether they belong to a city cluster or not. Starting at the center pixel of the city I want to select all ...
1
vote
0answers
122 views

What is a good data structure and file format for describing road network geometry AND topology?

I am trying to emulate the road network from OSM or Google (or Waze, etc.) locally, so that I can run some algorithms on it. For that, I want to represent these roads as graphs, where each edge would ...
3
votes
1answer
89 views

List group of line segments that are not connected to any other lines

In the image below, the system of lines includes 6 segments. This connectivity gives the appearance of an "island" as the internal segments are connected to each other and are not to the outside world....
1
vote
0answers
72 views

Which Network Analyst tool(s) or other geoprocessing tool(s) would be useful for this analysis? [closed]

I have been doing GIS for a few years now but never Network Analyst so I thought I would give this a go. I've built a multimodal network. Question I want to solve: Using street center lines (walking) ...
2
votes
1answer
145 views

Connectivity of Streams

I have a line vector layer containing streams (see image below). What is the easiest approach to determine the connectivity of each stream segment (eg. sum of upstream nodes)?
1
vote
1answer
197 views

Orphan road segments in QGIS?

I am working with OSM road data for a developing nation. Included in the dataset are various small networks of roads that are orphans or islands i.e. not connected to the main road network. For ...
2
votes
2answers
468 views

Calculating forest connectivity for raster

I'm trying to calculate some sort of forest connectivity value for each pixel in my land cover classification. I would like to do this by calculating how many other forest pixels are directly ...
0
votes
0answers
24 views

implement aspect in least cost path analysis to account for downhill and neutral ground movement [duplicate]

I am creating a least cost path model for large species that migrate over large distances across a rugged landscape (elk, deer, etc.) To calculate movement cost I am using a slope raster but I ...
2
votes
1answer
103 views

Find connected features by type in utility network?

I have a storm drain geodatabase with digitized direction flow. I am trying to find catch basins (upstream) that drain to other catchbasins (downstream) as opposed to a junction structure or an ...
4
votes
3answers
722 views

Habitat connectivity — how to map connectivity between polygons based on a separate polygon layer

I have a polygon layer representing a habitat type and another polygon layer representing water features. I want to be able to assign to each water feature whether it shares a connection via a ...
9
votes
4answers
12k views

Checking "connectedness'' of line shapefile in ArcMap?

I inherited a line shapefile in ArcMap that is used to represent a road network. The problem is that the road network is pretty large and it is impossible for me to: Tell if the end of each line (...
12
votes
2answers
3k views

Grouping connected linestrings in PostGIS?

I have a table of streets I've selected based on a set of attributes (let's say it's speed_limit < 25). There are groups of streets that are locally contiguous; I'd like to group these sets of ...
1
vote
1answer
86 views

Identifying connected drainage lines

I have a vector layer containing the potential drainage lines that have been computed from a DEM. I want to be able to click on any point and identify all the lines that are connected to my point of ...
1
vote
0answers
612 views

Line segment connectivity analysis in FME

I have a set of line segments, all of them snapped at the endpoints: As seen in the above image, the line segments appear in groups (4 in this example). Question: I would like to determine which ...