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

learn more… | top users | synonyms

6
votes
1answer
498 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 ...
1
vote
1answer
206 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 ...
2
votes
2answers
3k views

Formatting SQL queries for use in Arcpy?

I have to make an SQL query on a column having not adequat name "type_borne_id", I couldn't make SQL queries using arcpy.Select_analysis neither selectbyattribute, but when I use select_analysis ...
1
vote
0answers
73 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
150 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 ...
2
votes
4answers
1k views

Finding center point of MULTILINESTRING using PostGIS?

How to find the center point of MULTILINESTRING, which lies on the multiline? I am using SQL in PostGIS
1
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 ...
4
votes
3answers
2k views

Publish SQL Views from Postgres/Postgis to Geoserver

I've trying and reading how to publish a Postgres/Postgis View in Geoserver. I know that I can create an SQL View in Geoserver, but I'd like to define the View in Postgres, not in Geoserver. Does ...
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 ...
2
votes
1answer
149 views

Join Zip Codes Table to Nearest City from Second Table

I have two tables, siteareas and ziplookup. The former contains large cities in the US; the latter all US zips with lat/lngs. I have a foreign key into the former table in the latter: sitearea_id. I ...
2
votes
1answer
597 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 ...
26
votes
4answers
12k views

What is the best way to join lots of small polygons to form a larger polygon?

I have the following layer using SRID 27700 in postgis: It's every administrative region in the UK, and (as you can see from the colour grouping) each of them has a text field specifying the county ...
3
votes
1answer
742 views

Duplicate ObjectID in ArcSDE Table

After making a check in from an arcpad AXF file, i notice that there's duplicate ObjectID records. This ArcSDE PostgreSQL table is versioned and edited by Axf checkins and a .net engine application. ...
42
votes
2answers
6k 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 ...
6
votes
3answers
7k views

Creating join based on multiple fields using ArcGIS Desktop?

I have two feature classes in a File Geodatabase that I would like to join based on multiple fields. I've searched this site and Google and all I have come up with was to use the Make Query Table ...
1
vote
0answers
105 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
718 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 ...
2
votes
1answer
346 views

Direct DBMS sql queries and ArcSDE geodatabase

i want to make updates from Arcobjects on several tables stored on a ArcSDE 10.1 versionned geodatabase based on Postgresql 9.0.5 , none of these update require spatial data , and making these updates ...
7
votes
3answers
6k views

Select features by attribute if in Python list

I believe this will amount to largely a sql syntax question. Essentially, I am trying to complete a select by attribute in Python but based on the query of whether an attribute is present in a list. ...
1
vote
1answer
317 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 ...
2
votes
1answer
273 views

Creating a model to run a complex query

I'm just a rookie when it comes to creating models in ArcGIS. I have two shapefiles from which I need to calculate an AVG and a MAX erosion rate for individual properties. The two shapefiles are: ...
2
votes
1answer
208 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 ...
2
votes
0answers
235 views

Select a distinct attribute with maximum shape area

I am trying to manipulate a large dataset containing a lot of sliver polygons resulting from an overlay operations. (The eliminate tool is very time consuming to generalize them.) I identified the ...
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
375 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
3answers
363 views

Filtering dataset using SQL or Python in ArcGIS Desktop?

Using ArcGIS Desktop 10.0 SP4. I have a large dataset of sites that needs to be filtered down to a usable size. There is an attribute for the site_ID and another one for the site_type. There are ...
3
votes
1answer
322 views

Python SQL connection causes crash in ArcMap

I have the following code which I have striped down to just included the part that is causing a crash in ArcMap. import pymssql # Connect to the Research db using Windows Integrated Authentication. ...
4
votes
1answer
323 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 ...
3
votes
1answer
418 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 ...
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.
1
vote
0answers
141 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 ...
1
vote
2answers
388 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 ...
1
vote
0answers
354 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' ...
6
votes
2answers
7k 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 ...
2
votes
1answer
189 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 ...
0
votes
1answer
141 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 ...
1
vote
1answer
107 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 ...
1
vote
0answers
292 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 ...
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. ...
1
vote
1answer
511 views

Creating SQL query in ArcGIS Explorer SDK?

I am using the ArcGIS Explorer SDK and have run into an issue surrounding a query I would like to perform with SQL. I believe my query is built wrong or perhaps I am looking at the wrong fields. Would ...
0
votes
1answer
222 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)'), ...
7
votes
3answers
13k views

How to convert MultiLinestring to Linestring?

I have a multiline string and want to convert it to a linestring in order to use some functions that only work with linestrings. I used ST_Dump() and got a collection of my geometries. If I merge them ...
11
votes
3answers
3k views

Intersecting a raster with a polygon using PostGIS - artefact error

I'm using PostGIS2.0 to do some raster/polygon intersections. I'm having difficulty understanding which operation I should use, and what the quickest way of performing this is. My problem is as ...
0
votes
1answer
269 views

Vertex point is returning None

I have this multilinestring that has 48 NPoints. When I execute ST_PointN(line,5) it returns none. And to continue on, it returns None for everything after index:2 up to index:48. This is how my line ...
6
votes
1answer
2k views

Registering SQL Spatial View in ArcSDE and updating Row_ID?

I am having issues registering an inner join SQL view with a spatial column in ArcSDE. Any help would be much appreciated. Here is the background info: ArcSDE 10, SQL Server Enterprise 2008 R2, SQL ...
1
vote
1answer
589 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))" ...
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 ...