kartoza / stream_feature_extractor

A QGIS plugin to extract stream features (wells, sinks, confluences etc.) from a stream network

GNU General Public License v2.0

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We need to be able to compute associated node lists for each node #10

Closed timlinux closed 10 years ago

timlinux commented 10 years ago

Problem

Given a point layer add node_list and node_count and populate by generating node list, count from above method

Proposed solution

By using method to generate list of id nearby nodes, populate the list of upstream_nodes, downstream_nodes, and count them. For each attributes, we will need a specific field in the attribute table.

Expected outcome

We will generated information so that we can build a table like in comment below https://github.com/timlinux/stream-feature-extractor/issues/10#issuecomment-41037170

ismailsunni commented 10 years ago

add node_list and node_count

Does it mean, add new attribute in the attribute table?

generating node list

Do we put the id of the node in the node list or the geoposition (longitude latitude)? *I think it should be node_id, just for confirmation

timlinux commented 10 years ago

Ok so what we are aiming for is our extracted nodes layer to have a table like this:

id	node_list	node_count
1	10, 43, 21 99	5
2	12, 15	2

node_list should contain the id's of all other nodes that occur at the same position based on snapping distance (exclusive of the current node)
node_count should contain the len(items in node_list) plus the current node

ismailsunni commented 10 years ago

After discussion we agree to create a table like this:

id	line_id	node_type	upstream_node_list	downstream_node_list	upstream_node_count	downstream_node_count
1	1	upstream	5, 10 , 15	4, 7	4	2
2	1	downstream	12, 14, 44	5, 9	3	3

upstream_node_list : contains the id's of all other upstream nodes that occur at the same position based on snapping distance (exclusive of the current node)
downstream_node_list : contains the id's of all other downstream nodes that occur at the same position based on snapping distance (exclusive of the current node)
upstream_node_count : contains the len(items in upstream_node_list) plus the current node if it's a upstream node
downstream_node_count : contains the len(items in downstream_node_list) plus the current node if it's a downstream node