0
votes
2answers
38 views

sql query to get origins and destinations

I have a table of cities with an ID and geometry (200K rows) and a table of travels, with only two ID: idfrom, idto (7K rows) I'm wondering how could I select the geometries for each one in order to ...
2
votes
1answer
93 views

How can I move along a line (or path)?

Given a line (street, railroad, river...) I want to simulate a moviment inside this line. Example: See this picture: Say I'm in "Nagqu" and want to move to "Kunlunqial". In a time (t=0) I'm in ...
1
vote
0answers
104 views

Smoothing Lines in PostGIS

I want to smooth Lines in postgis, to be more specific, I want to smooth road data from OpenStreetMap. Basicly I thought of something like this scenario. This would be a possible road segment. I ...
2
votes
1answer
80 views

Draw a line and a buffer around it onto the spheroid

I need to draw a line between two points and create a buffer around this line. The only difficulty is that I need to draw not a "cartesian" line but a line that is laying on the spheroid. I tried to ...
1
vote
1answer
575 views

PostGIS, create line from points

I have a PostGIS table with position data of numerous vehicles and want to create lines from these points. Data can be selected by vehicle id and ordered by timestamp but how to create lines from the ...
-2
votes
1answer
215 views

QGIS and Python - create line with multiple points in postgis [closed]

How can I create a line, with Python functions, with many points that are records in Postgis? Thank you
13
votes
2answers
818 views

How can I merge/collapse nearby and parallel road lines (eg. a dual-carriageway) into one single line?

I have a shapefile from OSM which contains all the roads within a city. Larger roads (like dual-carriageways) seem to have 2 parallel lines. I'd like to collapse / combine those into 1 line so I can ...
3
votes
1answer
256 views

How to connect particular sets of points with (poly)lines?

I think my problem is quite easy to be solved by the most postgis-users, but i am a bloody beginner: i have a timestamped point-table representing GPS-tracked places of different cars. To distinguish ...
1
vote
4answers
438 views

How to find the center point of MULTILINESTRING?

How to find the center point of MULTILINESTRING, which lies on the multiline?
5
votes
1answer
174 views

Given 2 LINESTRINGs with common point, how to extract common point?

I have 2 LINESTRING geometries. I know both share a common point. Using PostGIS for Postgres, what is the cleanest way to extract the common point? Example with illustration: How do I extract the ...
6
votes
1answer
458 views

Filling a polygon with lines using Postgis

i need to calculate a specific distance in an area. The distance is calculated from parallel lines in a polygon, And i need to find out how many parallel lines (with x meters distance to each other) ...