Tagged Questions

0
votes
0answers
25 views

How to write a point-in-polygon query for Postgis?

I'm trying to write a query in Postgis which will return all rows where a dynamically changing longitude/latitude point resides within the geometric polygon of that row (in the geom column). This is ...
1
vote
4answers
57 views

Web service to see postgis polygons

Is there any website or web service where I throw a polygon postgis and he show me on the map this polygon. Example: I put this POLYGON((0 0, 1 0, 1 1, 0 1, 0 0)) and the service show me the ...
0
votes
0answers
44 views

polygon/raster intersection artifacts

I'm intesecting a polygon with a raster using PostGIS > 2.0. The outer boundary of the polygon is formed by the convex hull of polygons (building outlines plus safety margin) and the inner rings are ...
5
votes
3answers
163 views

How to insert a GeoJSON polygon into a PostGIS table?

I need to insert a polygon from GeoJSON to my PostGIS table. This is how the SQL query looks like. INSERT INTO tablename (name, polygon) VALUES ( 'Name', ST_GeomFromGeoJSON ( { ...
1
vote
1answer
52 views

Polygon to fill gap

Using postgis I want to fill a gap between other polygons. Can you help with some directions what functions to use ? Thank you and sorry if the question is rather noobish. Image to explain from ...
1
vote
2answers
127 views

How to add a polygon from GeoJson into Leaflet?

I try to use the following function to add polygons to my Leaflet map. function polygon(geojson) { alert(geojson); // alert for testing layer = L.geoJson(geojson); layer.addTo(map); } ...
1
vote
1answer
59 views

How to get polygons from PostGIS table to PHP array best?

Currently I fetch polygons from a database table using ST_AsText(). The results are in text format, like the following. POLYGON((84 104,212 48,321 122,243 179,275 238,131 240,84 104)) I am not ...
0
votes
2answers
78 views

Cannot insert simple geometry data

I installed PostgreSQL 9.2.4 and PostGIS 2.0.3 on my Windows 8 machine. Then I created a table using phpPgAdmin and added a geometry column using the following statement. SELECT ...
3
votes
1answer
45 views

How can I check if a multipolygon can be represented as a simple polygon?

I have a large (30m+ records) spatial data set I have imported into a PostGIS database. I did not expect to find multipolygons in the data set, but it does have a few of them. I'd like to take a ...
0
votes
1answer
93 views

Aggregate points with same values to polygons

I have a shapefile with 2M measurement points (each measurement point has a resolution of a 1/10). How can I aggregate points around each other if and create polygons out of it? They do not have to ...
6
votes
3answers
789 views

How best to fix a non-noded intersection problem in PostGIS?

I'm using a PL/R function and PostGIS to generate voronoi polygons around a set of points. The function that I am using is defined here. When I use this function on a particular dataset I get the ...
2
votes
1answer
78 views

What is the PostGIS function for retrieving buildings by road side?

I want to get information of buildings by the road side only. Assuming that the building table has multi-polygon geometry and the road table has multi-linestring geometry, what would be a pgSQL Query ...
3
votes
1answer
165 views

Merging multipolygon data into a polygon

I have a MultiPolygon representation of some shapes in POSTGIS, I am trying to convert them to Polygon data. I tried, st_geometryn(r.geom, 1) but that didnt work because the way polygons are ...
1
vote
0answers
186 views

How to handle postgresql/postgis geometry type errors in a function?

I have created the following function in PL/SQL to make a polygon from a set of linestrings: CREATE OR REPLACE FUNCTION _myfunction( _fid integer, _rid integer ) RETURNS VOID AS $$ ...
1
vote
0answers
61 views

footprint polygon from raster data with postgis

how can I create a polygon, containing the actual outlines (aka footprint) of a raster file with postgis? I just need the outlines of the data containing parts of the raster. ST_PixelAsPolygon ...
2
votes
1answer
421 views

How to take polygon centroid in Postgis

I have table with column name,Latitude and Longitude.I want to update this with polygon name and its centroid latitude longitude.I know there is a function in postgis st_centroid(geometry). But I want ...
-2
votes
1answer
195 views

Postgis error on select all intersetcs of a polygon [closed]

i can get all polygon on intersects this:-7.9245860488441 -37.122384500713,-7.9245860488441 -37.11904223938,-7.9233955716106 -37.1187601948 SELECT * FROM propriedades WHERE ST_Intersects( ...
3
votes
0answers
175 views

How to estimate the average width of a sidewalk? [duplicate]

I have a table with two polygons representing urban block with and without the sidewalk: geomBlock and geomBlockWithSidewalk. On my city we can approximate the polygons of geomBlockWithSidewalk to a ...
2
votes
1answer
237 views

How can I get the corners of a polygon in latitude and longitude?

How can I get the corners of a polygon -a square/rectangle, to be precise- in latitude-longitude format by using its geom value -or some other way, perhaps-? Thanks.
0
votes
1answer
233 views

To get attribute data of polygon layer by giving Lat/Lon

Is anyone having an idea about how to get attribute data of a polygon layer by giving Coordinates with in that polygon. Here i have tried with these codes.. SELECT * FROM kar_bbmp_198 WHERE ...
0
votes
2answers
186 views

How to retrieve a single polygon from a multipolygon layer in GeoServer

I have a multipolygon layer in GeoServer. The layer represents states within a country. I want to enable a user to search for a specific state, and then only the selected state to be displayed on the ...
2
votes
1answer
211 views

determine whether a circle intersects a county boundary in postGIS

I'm using PostGIS 2.0.1 and need to determine whether a circle (center + radius) intersects a county boundary (polygon). The query I'm using is this: SELECT DISTINCT(u.id) FROM siteareas_poly sa, ...
0
votes
1answer
216 views

How to remove polygon under other one?

Hi, lets say that green polygon is under red and part of blue with yellow stripes is also under red polygon. how can i make one polygon from every polygons that intersects my main ( red ) polygon ...
3
votes
1answer
713 views

Postgis - Converting 'geometry_dump' data type to a 'geometry' type

I am working with a dataset of property boundaries that has had ST_Union() run on it, thus all the polygons appear as a multi polygon in one row of a table. I would like to separate these out so I get ...
3
votes
2answers
467 views

Merging polygons that intersect by more than a specified amount

I am working with a dataset that contains a subset of property boundaries in a local government area, thus my dataset is made up of several thousand properties but not all are touching. Since it is a ...
6
votes
1answer
323 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) ...
6
votes
4answers
677 views

Output PostGIS geometry data as centroid or polygon depending on zoom level (GeoServer)

This is what I want: when I zoom out, cities of the country should appear as points and at a certain level when I zoom in, I want them to appear as polygons (showing the area of the city and ...
3
votes
2answers
467 views

Generate non-overlapping shapes from a buffer

I have a collection of points, and I need to generate shapes around these points. Let's assume that these points are locations of offices and that the shapes are the 'area of responsibility' around ...
16
votes
3answers
2k views

How can I calculate the average width of a polygon?

I'm interested in examining the average width of a polygon that represents the road surface. I also have the road centerline as a vector (which is sometimes not exactly in the center). In this example ...
6
votes
3answers
689 views

Can Polygons be generalized to MultiPolygons in GeoDjango?

I set up a model with models.PolygonField in geodjango, using postgres as database. I try to import shp into postgres. The problem is, shp (compiled with QGIS) mixes polygon and multipolygon, hence it ...
12
votes
5answers
4k views

How to use ST_Intersection?

Here's a quick summary about what I'm trying to do: I have 3 tables in Postgres, 'a' and 'b', each have a Polygon column, and 'c' has a Point column. What I'm trying to do here is to get the ...
6
votes
1answer
3k views

How to convert a String to OpenLayers.Geometry.Polygon using javascript?

First let me say that I'm using Javascript, jQuery, Java, GeoServer, OpenLayers and PostGIS. Using java class ResultSet I return this String: POLYGON((516000 2135000,515039.264020162 ...
5
votes
3answers
974 views

How can I display with OpenLayers the geometry returned from a ST_Buffer in POSTGIS?

Im using PostGIS, GeoServer and OpenLayers, and the thing is that i want to display the geometry result from a query like this: SELECT ST_Buffer(ST_GeomFromText('POINT(100 100)'), 500); To perform ...
10
votes
3answers
1k views

Optimizing a nearest neighbor calculation using PostGIS

I'm using PostGIS to calculate the nearest neighbors of polygons. What I want to calculate is the minimum distance from each polygon, to the nearest polygon. Thus far I have got great help from Mike ...
7
votes
1answer
775 views

Should I split MultiPolygons into Polygons?

In the system I'm implementing I have a table T1 with an associated geometry. Most of the geometries are a set of n polygons, with 10 < n < 100. At the moment in the table T1 I have a geometry ...
3
votes
2answers
143 views

How to bring polygons closer to a point?

I have some scattered polygons with a lot of space between them. I want to make a thematic map but all that white space doesn't look very good, so I want to bring the polygons closer to the center of ...
1
vote
0answers
86 views

Getting started with storing LoST and GML searching

I am working on a logging and search database application. The application will receive event records containing XML LoST values (RFC5222 Location-To-Service-Translation). These records will be ...
9
votes
2answers
733 views

PostGIS: split a polygon in a given ratio

Is there a convenient way to split a polygon into n parts, more-or-less equal in size in PostGIS?
8
votes
2answers
562 views

Splitting polylines using regions with PostGIS

I was wondering if it is possible to split a polyline on polygon boundaries (regions) in PostGIS, the picture below is of what we have at the moment and showing where I need the polylines split: ...
14
votes
2answers
3k views

How can I find a point inside a polygon in PostGIS?

How can I find a point that is guaranteed to be within a given polygon in PostGIS? I am aware of the ST_Centroid function. However, the centroid is not always within a polygon, see below: ...
3
votes
1answer
465 views

Find polygon that contains all linestring records in PostGIS table

I'm still pretty new to this stuff, so bear with me. In PostGIS how could I find a polygon that would contain all the linestring records in a given table?
16
votes
4answers
4k views

Separate polygons based on intersection using PostGIS

I have a PostGIS table of polygons where some intersect with one another. This is what I'm trying to do: For a given polygon selected by id, give me all of the polygons that intersect. Basically, ...