Acronym for Structured Query Language. A syntax for retrieving and manipulating data from a relational database.

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7
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1answer
926 views

Join based on maximum overlap in PostGIS/PostGresQL?

I have two sets of polygons in two tables. The sets overlap each other. For each polygon in set A, I would like to get the ID of the polygon in set B that it overlaps the most. I'm using PostgreSQL ...
1
vote
1answer
333 views

Should I query the tab/shp file or SQL (mapserver or geoserver)?

I have tab files (or shp) with information like residents , buildings etc... I need to be able to click a point in web map and query all data that fall in certain radius. I didn't decide yet which WMS ...
7
votes
2answers
13k views

Select by Attributes based on SQL wildcard range

I want to select all the records from a geodatabase table where the string starts with a letter, so I tried SELECT * FROM tbl_names WHERE "name" LIKE '[A-Z]%' This returned no records. After some ...
2
votes
2answers
2k views

Convert RT90 into WGS84

Goal: Gain WGS84 decimal to locate some cities in Google Map. Problem: I don't know how to convert the value of the RT90 coordinate system into WGS84 in SQL Server.
4
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1answer
2k views

Python script for constructing a WHERE clause from user input

I'm trying to construct a where clause from user input that will eventually be passed through as a SQL statement in the select tool or the select by attributes tool. I've started a script thats been ...
6
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0answers
1k views

Getting ST_Difference between two different tables in postgis [closed]

One table has a series of grid squares in it, and the other has millions of voronoi polygons in it. I need to create a table that has the difference between the two of the them so that I effectively ...
7
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0answers
75 views

How can I automatically split a spatial layer to a grid [duplicate]

Possible Duplicate: Divide vector in equal smaller parts in QGIS or similar I am a software engineer and the company I work for has a project that needs some spatial data manipulation in order ...
2
votes
1answer
472 views

Why is my PostGIS transformation not working?

I am using a PostGIS query to find the intersection of two streets, and then transform the results into lat/lon. The street database's current SRID is 6856, a projection I added to PostGIS myself; and ...
6
votes
1answer
540 views

Clarification of Logical Operators in a PostGIS Database

The following query returns this result: select count(*) from a , b where a.geom && b.geom; count ------- 66514 On a postgis 2 database. What does the logical operator AND (...
6
votes
2answers
8k views

ARCGIS 10 definition query to select the max value from a group

In ARCGIS 10 I am trying to do a Definition Query that will select the records that are the max values from a specific group. Here is what I have tried in the Query Builder but I am getting an "the ...
1
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0answers
3k views

How to populate data from postgresql using dynamic php\html listing

In the form I created, I need two fields to be dynamically populated from the database while the other fields will be manually entered and push to the database. I have written a script that is able ...
1
vote
1answer
213 views

run sql on Qgis

I want to do simple demo to our manager with quantum gis. i have buildings from my city with wgs84 projection on postgre sql database and also have non gis table which have who leaves this buildings (...
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0answers
76 views

Database has duplicate values after running pgrouting

I am a newbie with postgresql and sql statements so maybe it is a trivial question, I'm sorry for that. I am working on a postgis database and try to use the pgrouting function. My goal is to store ...
3
votes
1answer
153 views

Proximity query approach

Let's say that I have two tables in PostGIS, tracks and cities, each table has two columns, in both cases the columns are called name and way, name is a string, way is a geometry. I want to retrieve ...
1
vote
1answer
328 views

Cordenadas 2d transformacion a postgis desde QGIS

This is a three-dimensional shape file, I checked in ARCGIS, where the shape attribute indicates POINT ZM, This is the table fid 0 shape* point ZM atribut1 A atribut2 B ESTE ...
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vote
2answers
3k 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 ...
3
votes
3answers
2k views

How to Calculate length of polyline geometry for several tables in PostGIS?

PostGIS database contains several geometry (polyline) tables (with names "D1_r", "D2_r", "D3_r"). I calculate length for one "postgis layer" use request: SELECT sum(ST_Length_Spheroid(the_geom,'...
2
votes
1answer
698 views

How to create a point table from a remote csv file?

The current approach that I am using to load a csv file into a PostGIS enabled database on a server is the following: -- create table CREATE TABLE points( id int, lat double precision, lng double ...
48
votes
2answers
7k views

Acquiring ArcGIS-like speed in Postgis

I have been using Postgis 2.0 for 3/4 of a year now and while I really enjoy using it, excessive query processing time has rendered it basically unusable for my use case. I tend to do heavy ...
11
votes
3answers
2k views

How to interpolate GPS Positions in PostGIS

I have a PostGIS table of GPS positions for every five seconds: 2011-01-01 00:00:05, POINT(x1,y1) 2011-01-01 00:00:10, POINT(x2,y2) 2011-01-01 00:00:15, POINT(x3,y3) ... I'm looking for a query ...
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0answers
111 views

How to find loops in a network

I am a new in this field and need help, how to code using SQL spatial a function that retrieve loops in a network.The input, flag: Geography and barrier: Geography and two spatial tables, first ...
0
votes
1answer
786 views

How to select multiple features using advanced search SQL in QGIS

I have a layer of planning units covering a large area (there are over 16000 PU's). Three of the columns in the attribute table hold information about which planning units were included in the ...
4
votes
3answers
1k views

How to label features in QGIS using SQL statement?

In QGIS, I can't seem to find a way to define the features that I want to label using a SQL query? Is this possible? For example, I downloaded the OSM Natural shapefiles, and a lot of those features ...
2
votes
1answer
218 views

Postgis nested query trouble

I am having difficulty writing a nested postgis query. I have a single table from which I need to create a view in PostgreSQL. I have created the view with the following command create view rrop08....
4
votes
1answer
3k views

Performing Geoprocessing SQL Queries in QGIS from a PostGIS Database

This may be a dumb question, but is there way to run a PostGIS geoprocessing SQL query in QGIS? Specifically, I am thinking of running SQLs such as ST_Union, ST_Split etc etc. I have tried the ...
4
votes
1answer
601 views

Shorter Version of this SpatiaLite Query

I've been doing some spatial queries using spatialite, and they're large enough that a spatial index becomes a must. An example of using an index is given in the tutorial spatialite> SELECT ...
7
votes
1answer
2k views

Performance Gain Through GIST Index for Point in Polygon Query

I have two tables: locations(id,region_id,the_geom) and regions(id,the_geom). For each location point I want to determine the region it is located in: UPDATE locations SET region_id = (SELECT id ...
4
votes
1answer
409 views

ogrinfo SQL GROUP BY Clause

Does ogrinfo support a GROUP BY clauses? I could not find any good documentation of all the SQL syntax features it supports. I tried the following: ogrinfo . -geom=no -sql 'SELECT lsad FROM ...
4
votes
1answer
343 views

How to update attribute values of points outside an area?

I have two datasets in PostGIS 1.5 (on Postgres 9.1) one of polygons and one of points. I am hoping to create a SQL command that will select all of the points in a dataset that are not within of the ...
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1answer
644 views

Passing parameters to PostGIS SQL queries in Python: weird behaviour

The following code always goes to the except section and I do not understand why..Any help would be much appreciated. l = None c = conn.cursor() try: s = "SELECT ST_NPoints(ST_GeomFromText(%s))" ...
3
votes
1answer
442 views

SQLServer generating invalid WKT

I am a GIS novice using SQL 2008, with C# and the NetTopologySuite WKTReader type to work with some geometries. I have some data which I have been able to save into the database but when I read back ...
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0answers
149 views

Acceptable Reduce() amounts for google maps zoom levels?

I'm using SQL Server Spatial to return large polygons to Google Maps for display. Given that google maps has a zoom scale of 1 - 20, I would like to reduce my polygons (reduce function uses the ...
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2answers
401 views

Select points within a relative number range

I need to select points that have attributes that are within a relative number range of each other. For instance; given the following numbers: 95,705,139,65,537,266,525 and 188; I need to find all of ...
3
votes
1answer
2k views

ESRI File Geodatabase - Trying to use CURRENT TIME in Definition Query

Is it me, or are the date functions in the file geodatabase a total nightmare. Anyway, I am trying to set up a fairly simple definition query that contains a subquery with a date comparison. My ...
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0answers
366 views

Add building height from xyz points in PostGIS

I have been trying to get this query right and just can' seem to. I have a building polygon table with over 7 million polygons, indexed I then have a grided height XYZ table with attribute 'height' ...
0
votes
1answer
147 views

Postgis reorder mixed up linestring chunks / max_segment_length(linestring)?

I imported ~1000 paths from somewhere into my postgis database to a linestring field. I had the problem that the paths were divided into chunks, and those chunks were mixed up in some cases. Suppose ...
2
votes
1answer
195 views

SQL Plus error using sdeversion

I'm new to SQL Plus and I have a question. I've created several versions of a feature class located on a SDE database. I want to use ArcSDE Administration Commands found here but I'm getting an error ...
1
vote
1answer
112 views

Read height data from Meridian 2

I'm having difficulties reading the Gridded height data (OS Meridian 2). I'm loading with OSGB 1936 reference system but have trouble finding the lat/lon data for each point. i.e.I open the attribute ...
5
votes
2answers
1k views

Changing Buffer table geometry dynamically in PostGIS using plain SQL

I have two tables in PostGIS, a point and a point_buffer table. The point table has a buffer_distance field, with a default value say 200. Now I want to change the buffer table geometry whenever I ...
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0answers
315 views

Manifold 'Link drawing to query' - can I do this in QGIS?

Manifold GIS allows the creation of dynamic drawings linked to queries. Unfortunately I do not have access to Manifold as my employer refuses to pay for it, so am currently investigating alternatives....
1
vote
1answer
1k views

POSTGIS query of point feature. How to find nearest point to query location?

I am querying a point feature using a POSTGIS request fired in Javascript. The decoded URL looks like this and returns great results for polygon features. http://test.tablelocation.com/api/v1/sql/?q=...
0
votes
1answer
224 views

Running database operations against a stored GIS geometry

I'm using Quantum GIS and Postgres with the GIS extensions to store shapefiles that I'd like to run point in geometry and point in union geometries against. While it's easy to save and load the vector ...
0
votes
0answers
62 views

postgis minimum distance among many points [duplicate]

Possible Duplicate: Nearest Neighbor calculation in PostGIS Is there a way to achieve the following: SELECT ST_AsText(a.geometry), min(ST_Distance(ST_GeomFromText('POINT(10 20)'), a.geometry))...
4
votes
2answers
1k views

Selecting points not snapped

I have a point layer and a polyline layer. I want to select all points in the point layer that are not snapped to a vertex in the polyline layer. How can I accomplish this? I'm using MapInfo and ...
4
votes
2answers
1k views

What is the best approach to using IQueryFilter.WhereClause in ArcObjects?

What is your preferred / best approach to using IQueryFilter.WhereClause statements in ArcObjects (e.g. when selecting features by attributes)? You need to check the source type (shapefile / personal ...
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vote
1answer
389 views

How to correctly use cursor.execute() with PostGIS?

I do not understand how the operator works some times... Here is an example that works, "SELECT ST_Distance(ST_GeomFromText('POINT(-3.16496271127842 55.9262620593642)'),ST_GeomFromWKB(a.geometry)),...
6
votes
2answers
1k views

How to fix pgRouting error “starting vertex not found”?

I've posted on here before about my battles with drivetime polygons and got some sensible suggestions back, so having Googled myself stupid over this I'm turning to you once again in the hope of a ...
4
votes
1answer
2k views

Good place to get Country, State, City, and Zipcode information?

I'd like to populate a database with common location information. I'm not entirely certain that addresses across the globe have similar or even the same entities as the Country, State, City, and ...
3
votes
1answer
766 views

ArcGIS Select Analysis using Unique Values from Field

I am trying to create separate shapefile using Select analysis with ArcPy by doing an SQL query to create them based on a unique value from the field. I want to create a list of the unique values in ...
0
votes
1answer
102 views

How to query distict row with the same label from different linestring with multiple segment?

I have a multilinestring street table in postgis with two columns: label and prefix. This table has 2 different roads with the same name and each road contains multiple segments. Roads were splitted ...