How to “group” based on consecutive occurrences of an element in a column in postgres
I have a table that, when ordered, describes a path by point descriptions in each row.
A column tells whether a row is a special (stop) point within that path and is empty otherwise. The path starts and ends with such a row and has many in between. What I want to do is create line segments from the point rows that start at such a row and also end at such a row.
point stop
1 yes
2
3 yes
4
5
6 yes
I want to call ST_Makeline from PostGIS to turn the ordered points into these line segments. How can I enforce that ST_Makeline, being a "summary" function is only called for the inclusive point groups 1 to 3 and 3 to 6?
postgresql postgis
asked 3 mins ago
telegotttelegott
1
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I have a table that, when ordered, describes a path by point descriptions in each row.
A column tells whether a row is a special (stop) point within that path and is empty otherwise. The path starts and ends with such a row and has many in between. What I want to do is create line segments from the point rows that start at such a row and also end at such a row.
point stop
1 yes
2
3 yes
4
5
6 yes
I want to call ST_Makeline from PostGIS to turn the ordered points into these line segments. How can I enforce that ST_Makeline, being a "summary" function is only called for the inclusive point groups 1 to 3 and 3 to 6?
postgresql postgis
asked 3 mins ago
telegotttelegott
1
New contributor
telegott is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
I have a table that, when ordered, describes a path by point descriptions in each row.
A column tells whether a row is a special (stop) point within that path and is empty otherwise. The path starts and ends with such a row and has many in between. What I want to do is create line segments from the point rows that start at such a row and also end at such a row.
point stop
1 yes
2
3 yes
4
5
6 yes
I want to call ST_Makeline from PostGIS to turn the ordered points into these line segments. How can I enforce that ST_Makeline, being a "summary" function is only called for the inclusive point groups 1 to 3 and 3 to 6?
postgresql postgis
asked 3 mins ago
telegotttelegott
1
New contributor
telegott is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
I have a table that, when ordered, describes a path by point descriptions in each row.
A column tells whether a row is a special (stop) point within that path and is empty otherwise. The path starts and ends with such a row and has many in between. What I want to do is create line segments from the point rows that start at such a row and also end at such a row.
point stop
1 yes
2
3 yes
4
5
6 yes
I want to call ST_Makeline from PostGIS to turn the ordered points into these line segments. How can I enforce that ST_Makeline, being a "summary" function is only called for the inclusive point groups 1 to 3 and 3 to 6?
postgresql postgis
postgresql postgis
asked 3 mins ago
telegotttelegott
1
New contributor
telegott is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 3 mins ago
telegotttelegott
1
New contributor
telegott is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 3 mins ago
telegotttelegott
1
New contributor
telegott is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 3 mins ago
telegotttelegott
1
asked 3 mins ago
telegotttelegott
1
1
New contributor
telegott is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
telegott is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
telegott is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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