A command used to retrieve information from a database

learn more… | top users | synonyms

3
votes
1answer
277 views

How to filter layer of osm data?

I have a table osm_roads that has a column named geometry geometry geometry(LineString,900913). If I want to filter a city to draw districts, I cannot do it by geographic coordinates? What if in ...
2
votes
1answer
844 views

How to save WMS getFeatureInfo points to a layer?

This may be a poorly worded question, because I am not sure of the exact terminology, but I'll give it a shot. I have imported a vector layer from a WMS server into QGIS. I am able to query the ...
5
votes
2answers
1k views

PostgreSql query problem with aggregate functions

I need help with a PostgreSql query. I need to find all parcels which have bigger area then average. I'm using this query: SELECT OBJECTID FROM parcela WHERE ST_Area(geom)<(SELECT ...
5
votes
1answer
2k views

Querying Data with a 1-Many Relationship Class

I have created a relationship class similar to the one I posted about in this question. Essentially, there is a point feature class representing a location of vegetation clearing with attributes ...
13
votes
3answers
5k views

Idiots guide to expressions for QGIS

I have no formal training in GIS and have learned on the fly with ArcGIS 9.3 at work and have been dabbling with QGIS on my own time for my business. Is there any resource recommendations ingeneral ...
5
votes
1answer
675 views

How to run custom queries on vector layers and display results?

Is there a way to display the result of a query in QGIS? For instance : To get the total number of inhabitants : SELECT SUM( inhabitants ) FROM countries To get the total density : SELECT ...
0
votes
1answer
770 views

How to make Stored Queries for WFS 2.0.0 in Geoserver

I am a new user of Geoserver. I have created a WFS and also could connect it with the QGIS WFS 2.0.0 Client plugin available now. But as like the default WFS link in that plugin I am not able to make ...
2
votes
1answer
267 views

How to filter or query data in GRASS?

I have a PostGIS dataset with just over 2 million rows. Each row has a PostGIS geometry point value and several attributes. I'd like to do some analysis on certain subsets of the data, but I can't ...
10
votes
3answers
1k views

How to speed up queries for raster databases?

I have a raster database in postgresql/postgis with these columns: (ID, rast, data_of_data). 'rast' is the column that has raster files in WKT format. An example query to find the DN value of a ...
2
votes
2answers
498 views

How fill length and feature count in PostGIS table for each polygons

I'am new to PostGIS/PostgreSql. I have a database which containts two shape-files : polygonal layer towns and linear layer of roads To calculate the length and feature count of 'Streets' inside ...
2
votes
2answers
1k views

Spatial index to speed up the query

I have spatial table in PostgreSQL 9.2 / postgis 2.0 that I have to extract some information from it. But my query is hopelessly slow. How could I make use of spatial index to improve the performance ...
3
votes
2answers
161 views

Multiple queries in a row

I have osm data imported into PostgreSQL with osm2po tool (wich makes the data routable). Also I have imported data relationed with nodes and node_tags with osmosis tool. I need to obtain a set of ...
3
votes
0answers
453 views

How do I determine appropriate Date query syntax for a layer?

I'm writing a web mapping query tool to query Esri mapservice layers by date using the REST API. It has been said that the syntax depends on what kind of database is behind the mapservice layer, as ...
4
votes
1answer
351 views

Improve database performance for geospatial

I have a database with osm data imported with osmosis tool. I want to search for the nearest POIs from a given point. For this purpose, I perform this query: select id from nodes where ...
4
votes
2answers
787 views

Spatial query of raster data

I have population distribution data as a raster layer and exposure contours as vector (polygon) layers. What I'd like to do is use the vector layer to estimate the population indicated from the raster ...
3
votes
1answer
186 views

Editing and Deleting Query Tables in ArcMap

How do I edit the query for a Query Table after it has been created? How do I permanently delete a Query Table? Even after I do right-click -> remove, it still appears in dropdown lists.
7
votes
2answers
329 views

How to run a spatial query with a raster and vector layer in QGIS?

I have a soil map (vector-polygon layer) and a map of the crops farmed in the same area (raster layer, from the US Cropland Data Layer). I would like to calculate for a given soil type, the surface ...
3
votes
1answer
799 views

Using Google Earth to query database

I've been reading about using Google Earth to query data (this article) and I'm interested in learning how to make one of these. I just have a couple of questions: 1. Is this possible with the free ...
3
votes
3answers
1k views

How to join Shapefile and Excel data without unique ID column?

I have one huge shapefile with lots of roads (polylines) along with various attributes and I have an Excel file containing some of these roads by three same attributes (road no., section no., length) ...
3
votes
1answer
265 views

How to query against time

I have a date-time field in a feature class which I want to query. The field has values like "2011-01-01 00:00:29". I want to query the data between the time 00:06:00 and 00:12:00. The date does not ...
2
votes
2answers
1k views

How to query multiple features from Geoserver WFS?

Are there any methods to query several features by id other than one entry by a single url request? The scenario is I store around 200 point layers in PostgreGIS. Each maintains 100k entries GPS ...
1
vote
1answer
287 views

I'm trying to zoom to a graphic, but nothing happens?

I'm trying to zoom to a graphic retuned from the query; query.OutSpatialReference = MyMap.SpatialReference; query.ReturnGeometry = true; After this query I used ...
1
vote
2answers
88 views

How to query points that fall outside their designated regions?

I have a shapefile with 250 points. Each point has a region attribute. In another shapefile I have all the possible regions with their names (it is polyline geometry). Unfortunately the coordinates ...
2
votes
2answers
1k views

query raster in ArcGIS 10

I am using ArcGIS 10 (includes spatial and geostatistical analyst). I have a raster (GRID) with a value range of -167 to 18. I would like to query the raster and create a new one with only the values ...
7
votes
3answers
234 views

What would be 'normal' processing time for a large postgis query

I have two datasets which I want to spatially join (with an intersect). The first dataset consists of 9 million addresses. The second dataset consists of 12.000 neighbourhoods. I want the add the ...
6
votes
1answer
2k views

How to find the nearest point by using PostGIS function?

table A: lat | long | the_geom | code | sign 13.8433095 | 100.6360357 | 0101000020E61.... | ABC | start_point 13.7544738 | 100.5459646 | 0101000020E6..... | ABC | end_point 13.4124215 | 100.6232332 ...
8
votes
3answers
582 views

How to select only Spatial tables from the postgres database?

My database contains both Spatial and Non-Spatial tables, but I want to retrieve only Spatial table from the query. Any suggestions to select only Spatial tables. 'the_geom' is the geometry column in ...
2
votes
1answer
823 views

How to query attributes cross-table in QGIS?

is it possible in QGIS to query a layer with data from another layer? And if so ... how is the syntax for that? Usecase: I have a lot of image-position points and a lot of monitoring sites. I would ...
1
vote
1answer
197 views

Using database tables with bigint columns in ArcMap query layer

I am very new to GIS and am using the ArcMap 10 program. Currently, I am trying to set up a query layer from a remote database. I am able to connect to the database, but I am having trouble making ...
1
vote
1answer
2k views

Setting a query loop

I am looking to apply a Select By Location protocol to my data, but need to first query individual IDs in my target and source layer (the same ID in each table, one at a time). How do I loop through a ...
3
votes
1answer
355 views

TO_DATE query on ArcSDE for Oracle dataset failing?

I'm trying to use TO_DATE to query an Oracle SDE dataset. It's not working in the javascript API application so I tried to query the rest end point directly and I get the error: "Unable to perform ...
1
vote
0answers
1k views

How to fire a query from OpenLayers to GeoServer to fetch 'the_geom' column in PostGIS table?

I am coloring the polygon shapes of world_country. I have OpenLayers in my UI, GeoServer as server and PostGIS as db. All I want is fire this query: select the_geom from world_country where ...
2
votes
1answer
951 views

Geometryutil, simplify polygon, querytask and query fault error

One of the tools in my app is to draw freehand polygons (counties) to show points (companies) in each county. Everything works great but if the user creates an intersecting polygon then I have a ...
1
vote
1answer
107 views

Does linux suport “like '%c'” filter(cql_filter)

I can execute the following request: http://My.host:8080/geoserver/wfs?request=GetFeature&version=1.1.0&typeName=topp:states&cql_filter=STATE_NAME like 'California' But I can't execute ...
4
votes
2answers
2k views

Selecting MAX values within records with the same name

I'm working in ArcMap 9.3 and I've never dealt with that kind of queries... I need to Select the MAX value from column [A] for each set of records in the table which have the same value in column [B] ...
1
vote
2answers
62 views

2 Similar Queries Run at Vastly Different Speed in a Very Surprising Way

I have to be very careful here. Both queries are so similar that the only different is the area searched. What's surprising is the query that run on BIGGER AREA, and naturally yield MORE ROWS, is the ...
10
votes
5answers
3k views

How to identify duplicate attributes in a field?

I have a point shapefile with thousand of points. It has an ID code field that supposed to be unique. Every now and then the data entry clerk wrongly type the id creating duplicates.Right now I'm ...
1
vote
2answers
310 views

postgis, mapserver & openlayers: if data is not in table give an error / pop-up

I have created a website with postgis, mapserver & openlayers. On the website you can enter a postal code and then a drivetime isochroon is created. The problem now is that you can enter ...
11
votes
3answers
1k views

Are personal geodatabases better suited for quickly querying indexed attributes than file geodatabases?

I'm preparing data for an ArcGIS Engine application that queries the data to search for an address. Sometimes we search just on the street name field, just on the house number field, or both. When ...
1
vote
0answers
399 views

Cannot join feature layer with SQL Server table with query built in it in ArcMap

I need to join a feature layer with a SQL Server View with a common field in ArcMap. The View was successfully added to ArcMap as data table with some query built on it from Query Builder. When I ...
6
votes
1answer
555 views

Need to learn more about Precision and Accuracy

I am currently taking Introduction to Image Interpretation online and there is a section in it that talks about Precision and Accuracy. I wanted to know if someone out there has any good information ...
3
votes
1answer
4k views

How to filter features in a layer?

I am trying to display certain features in a shapefile-based layer using QGIS. I have found the subset function in the properties panel, which does exactly what i want, but is too tedious given that I ...
3
votes
0answers
285 views

How to get distinct values from multiple columns in GeoTools?

Is there a way to get distinct values from multiple columns in geotools? I know I can get unique values from a column like this: SimpleFeatureSource featureSource = ...
2
votes
1answer
854 views

Why does my PostGIS query fail with “current transaction is aborted”

I'm trying to create a vector layer in a QGIS project using a PostGIS query. QGIS is returning the following error: Query failed 1 cursor states lost. SQL: CLOSE qgisf1 Result: 7 (ERROR: ...
0
votes
3answers
524 views

How can I query and categorize a shapefile using MS Access?

Is there a way to categorize locations by lat-long in MS Access using caparisons to shapefiles?
5
votes
1answer
2k views

How do I perform a proximity search with Postgis?

OK, so I downloaded the Geonames database (cities1000) and wrote a small Ruby program to import them into my table (geo_cities). I then added geography column called geog. So after all of that, I ...
2
votes
1answer
1k views

PostGIS UPDATE Statement with ST_Contains(table1.geom, table2.geom)

I'm strugeling with a query I should write to UPDATE my dataset. First of all, I have 2 tables containing data and I need to mix it. Tabel 1 -- lets call it names: name_str the_geom (points) ...
2
votes
1answer
348 views

How to query OSM tags by polygon?

I do not know whether something like this is possible but nonetheless. If I understand OSM correctly all objects essentially have associated tags based on type of object (street, building etc) ... ...
1
vote
1answer
526 views

Administrative level and coordinates from Yahoo GeoPlanet WOEID

The Yahoo GeoPlanet data can be freely downloaded from: http://developer.yahoo.com/geo/geoplanet/data/. If I understand it correctly, each WOEID corresponds to a unique location on earth, with ...
5
votes
3answers
4k views

How to fix performance problem in PostGIS ST_Intersects?

I'm a newbie in postgis and I have a problem in query performance. This my query: SELECT DISTINCT ON (userid) userid ,ST_AsText(position), timestamp FROM table1 WHERE ST_Intersects ( ...