1
vote
0answers
63 views

OpenLayers - Add points at vertices of line while drawing line

I would like to create points while I draw a line on my map in OpenLayers. That is, at each vertices of a line and at the end points there is a shape like a square, circle, or diamond. I have this ...
3
votes
1answer
86 views

Find the closest line vertex from the linestring using PostGIS

How to find the closest line vertex from a linestring? ST_ClosestPoint will give a point which is not from the linestring.
0
votes
1answer
21 views

ValueError when instantiating LineString from a mix of tuples and Point objects

I'm new to Shapely, and tried instantiating a LineString object from a mix of tuples and Point objects like this: >>> LineString([Point(1,2),(2,3),Point(3,4),(5,5)]) I get the following ...
3
votes
1answer
89 views

Calculate distance between point and linestring and how to represent that on QGIS?

I have loaded my data with osm2pgrouting and I have my network with ways (Linestring) and nodes (Point). The problem is : I have a database of doctors addresses (point) and I should calculate the ...
4
votes
2answers
166 views

How to speed up a query for nearest linestring to point data

I have processed a Strahler stream order layer with a lot of river linestrings (type: Multilinestring) and their corresponding strahler number (see information here). Besides I have a point layer. I ...
0
votes
1answer
68 views

Can I use Point as the geom type in pgrouting?

in my table i have the field geom(POINT, srid) and its populated, this table also have the source an target field witch is blank(just like pgrouting guide). I tried the function pgr_createTopology() ...
0
votes
2answers
228 views

Create multi-line from point in PostGIS

I'm working on an old table where polygons are stored as points. Now, I want to migrate these points to PostGIS and store them as polygons (or multi-polygons). The table structure is as follows: ...
0
votes
1answer
131 views

Defining a WHERE clause from a subquery for a query to create a handy view

It is about my implementation from an answer of this question. It is more an postgresql issue than a GIS issue, whereas it is about geometries and spatial queries. I want to create a view from the ...
4
votes
1answer
473 views

How to create linestrings with a definite angle and length, that are fixed to a point

I want to create linestrings with a definite angle (e.g. 160°) and length (e.g. 2m) that are fixed to a number of points of another linestring. So, I want to use the ST_DumpPoints function to find the ...
1
vote
2answers
255 views

Extract a LineString from LineString by two Points

I am using PostGIS2.0 and PostgreSQL9.3. I have LineString in Spatial-Ref 4326 like geom:= ST_GEOMETRYFROMTEXT('LINESTRING(60.7014631515719 56.8441322356241,60.7023117507097 ...
0
votes
1answer
225 views

Linked point geometries to linestrings in Spatialite

I have been parsing Canada's radio system frequency open data. It's a single large table per province, containing point geometries for each station callsign. Where a point-to-point link is defined, ...
1
vote
1answer
360 views

how to split a line by a point which is on the line but not in the linestring itself?

i need some help with the following: i have a linestring - geom i have $lat,$lon (using some php syntax) i have an osm table with the roads geom, i am trying to get closest point, and then split ...
7
votes
4answers
526 views

How to calculate the “depth” of a linestring using postgis

I have linestring features, which look like bent linestrings, hemicycles or convex or concave linestrings. In the moment I can select the distance between the startpoint and endpoint of each feature. ...
3
votes
3answers
2k views

How to extract POINT from a [LINE|MULTILINE]STRING

I'd like to create a vectorLayer in QGIS to display all the points that form a LINESTRING or a MULTILINESTRING stored in a PostGIS DB. I think that I need to transform all points of LINESTRING (or ...
3
votes
2answers
1k views

Create point to a center of polyline

I'm trying to create a points in the middle of polylines. The data is now in the form of shapefile. Is there an easy way to do this? Cheers, Sanna
5
votes
1answer
428 views

adding multiple points to a linestring in PostGIS

Though a newbie to PostGIS, I'm having trouble solving something that I think should be farily straightforward. I have two linestring tables, both consisting of simple, 2-node line objects: one has ...
8
votes
2answers
753 views

How to add vertices to existing linestrings?

If I have Linestring(1 2, 1 5, 1 9) and a Point(1 3) Is there any function that can merge linestring and point preserving the order so output would be: Linestring(1 2, 1 3, 1 5, 1 9)
0
votes
1answer
234 views

What is the fastest way to identify the two nearest linestrings using PostGIS?

I want to be able to identify the closest roads to two points that are generated through geocoding (a start and end address). The points will likely be near a linestring. Two approaches that I have ...
1
vote
2answers
2k views

How to offset point perpendicular to line direction in PostGIS

I have a postgis table of points, that are sitting on road centerlines (I've linear referenced them). And the second table with road centerlines themselves. The point table also has a field roadid and ...
2
votes
3answers
567 views

How to create a efficent linestring out of geography points using postgis

I'm trying to create a linestring out of geography points. At the moment I'm doing it like this: select ST_GeographyFromText(ST_Makeline(a.record_point)) from ( select (record_point::geometry) from ...
2
votes
1answer
109 views

Access points with PostGIS

I have a PostGIS table with linestring geometries and point (A) on it and I need to detrimine points (M) which located M meters from A. Distance is measured along linestrings. Any thoughts?
7
votes
2answers
1k views

For a given feature find the closest point along a given path

Looking for a Java based (foss4g) solution for the following: I am using a path along with a buffer to find features that are along the path. For each of the features returned I want to find the ...