A command used to retrieve information from a database

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2answers
57 views

Find the majority area within another area

I have a survey grid overlaid unto several administrative areas. Both are polygon features and I have performed a union on both features in order to determine the areal contribution of the segments ...
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1answer
146 views

Circles created by points inside bounding box query - PostGIS

The table that i want to perform this query has 3 columns: id, the_geom and seen_count. The query i've been using to get points inside a bounding box is as follows: SELECT id, ST_AsGeoJSON(the_geom) ...
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2answers
415 views

ST_DWithin uses Geometry or Geography type

assuming I use the following query to match the locations to a poi within 10km distance: SELECT poi.poi_id, h.loc_id, (ST_Distance(poi.geom,h.geom)*111.111) as distanceinkm FROM iut_poi_transl AS ...
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3answers
104 views

Comparing polygon attributes that share the same parcel?

I'm new to ArcGIS, or at least anything beyond the basics, especially ArcToolBox. so the answer might be extremely simple. Basically I have one layer of building footprints, and another layer of ...
0
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1answer
76 views

How to select all cities in Germany from city and country layer?

I have 2 layers: layer_1: countries of europe, layer_2: cities of europe I want to create (and then save) a layer_3 which would be all the cities of Germany. Is there any good tutorial of how can i ...
1
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1answer
507 views

Why isn't my select by attributes query working?

I'm running ArcMap 10.1. I have a point feature class joined to a table and am trying to query a field. If I do [field] = 'TEST', it selects all the fields. But if I do [field] LIKE 'TES%', it ...
2
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1answer
298 views

Help building SQL query to get a list of streets of a city

From two layers in PostGIS (osm_places and osm_roads), I would need to have the roads belonging to a certain city. It would be fair enough to get the street names of all streets in a radius of X ...
2
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3answers
379 views

How can I export or query all hospitals from Open Street Map?

I'd like to extract all the hospital locations in the US from Open Street Map as a reference for my geocoding project. I know how to get all the OSM data for a small area with the QGIS plugin but not ...
3
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0answers
248 views

Select features within a country or bounding box effectively using PostGIS

I imported the planet OSM file into a PostgreSQL 9.2/PostGIS 1.5 server using osm2pgsql. I now want to select certain map features which lie within the bounding box formed by a countries borders, e.g. ...
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1answer
66 views

For each polygon, return yes/no value if it intersects another layer

I have a polygon grid overlaying several other polygon vectors. I wish to visit each polygon in the grid and ask yes/no if each of these layers fall within the grid cell or not. I can do this easily ...
0
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2answers
179 views

PostGIS, distance between two users

I have a simple table (location_test) with three column (name, geom , jid). geom is a geometry column with SRID 27700. I set the user's geometry position with: UPDATE location_test SET geom = ...
2
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2answers
638 views

Built a query for polygon Shapefile in R

I use the package maptools to read in Shapefiles in R. I would like to know if there is a function that can built up a query/subset to select only some Polygons based on a specific attribute in the ...
3
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2answers
110 views

How to query for a specific point, within a specific polygon?

I have a shapefile points layer, with each point representing either Marginal, suboptimal, or optimal conditions. I want to find only the marginal points within a specific polygon from my catchments ...
2
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1answer
206 views

Merge attribute data using spatial query in QGIS

I have 2 vector layers that I wish to correlate attributes - a shape file containing boundary polygons and a shape file containing point locations. I'm using the vector>spatial query tool to generate ...
3
votes
1answer
129 views

Filter contour lines in QGIS

I have a shapefile of contour lines, with an ALTITUDE attribute with the height ASL in metres. The source data is in 0.5m intervals, but I'd like to filter it down so I get contour lines at (for eg.) ...
1
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2answers
294 views

What are the options for working around the max number of records returned for a query task on ArcGIS Server 9.3.1?

I'm trying to return polygon features that intersect a larger polygon which defines my area of interest. It is working in some cases, but when the area of interest gets large (7000 intersecting ...
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1answer
606 views

Querytask/query - executed select

Is there a way to get to the query condition, which is executed under the querytask ? I have an example, which is actually a copy of this ArcGIS example ...
1
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1answer
188 views

How can I change SQL query through a layer of an action (python)?

I have three layers from three diferent database tables. When I click in other layer I want to change (with an action) the query of that three layers. How can I do that? Thank you
4
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3answers
401 views

How to create Where Clause from user input via Python list?

I am trying to perform a query based on values in a Python list. The where clause will then be used in an Update Cursor, so that the rows NOT equal to the values in the list will be deleted. This is ...
2
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1answer
326 views

Reading OGC geometry data from SQL server using R

I would like to write a script in R that creates a map using OGC geometry data that is stored on a Microsoft SQL server. Is there a way to read OGC geometry data using a query passed from R? Maybe ...
0
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1answer
107 views

In QGIS can I show just the lines in a Postgis query? How can I do that?

I have three tables in Postgresql, each table with one layer of lines. I want to show the path of an initial line to another final. Is it possible executing a SQL query? Thanks My three tables are ...
4
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1answer
680 views

How to Find points in a Kilometre radius

I am new to PostGIS and GeoData. I need to find where the lightning has stroke by a period of time and kilometre radius based on a given location. I have given lon/lat and my table is: latitude ...
1
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1answer
212 views

How to get the nearest line to a feature?

I have features on map, and i want to get the nearest poly-line to each one. How to write spatial query to get the nearest one. I tried to use ISpatialFilter but i couldn't reach anything.
4
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1answer
543 views

How to speed up an st_intersects() query?

I have a "huge" spatial database: 72GB, 200 millions documents with geometries (points) I have a GIST index on the geometries the database: CREATE TABLE resources ( id bigint NOT NULL, accuracy ...
2
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2answers
300 views

Selecting lines occupying identical positions in MapInfo or QGIS

I have two shapefiles from a client, one is their entire network (complete with unique IDs) and another a selection I need. However the selection file does not have unique IDs but the entire one does. ...
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0answers
421 views

ArcGIS API Javascript - FeatureLayer from json: problem with queries and popup

Hello everybody I've tried this code proposed by Derek Swingley in JSFIDDLE: JSFIDDLE-FeatureLayer from JSON Everything "seems" to work fine, but not always. If you go down to the closer scale (level ...
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1answer
42 views

Isolate And Save Raster Features From Existing Multivalue Raster Map

I have Cyprus Corine map with 44 different types of land use. I want to run a raster calculator query or any other way to isolate the areas with codes 10 to 22 and 26 to 34, all other values 1 to 44 ...
1
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1answer
81 views

How to get routes in the database that intersects circle?

I have routes (linestrings) recorded in the database. I want to create a query which returns the routes that have some commonality with a circle whose center and radius are passed as parameter. I ...
8
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2answers
2k views

How can I more efficiently select related records?

Below is the code I'm using to replicate the "related tables" button in ArcMap. In ArcMap that button selects features in one feature class or table based on the selection of features in another ...
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0answers
162 views

Query to find lat/lon of a house by street.name & house.number

How can I get house coordinates (latitude, longitude) by street.name and house.number? If it is possible, how I can get it? Many thanks!
4
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3answers
1k views

How to join two tables using date, time, lat and lon as common field?

I am sorry if the question is elementary but I did not find any clear discussion or guide to understand how to run a query in postgresql. So that a pointer to another website would be also useful. ...
8
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3answers
2k views

How to query all records (>1000) and export to csv?

I posted in arcgis forum but never got any answer. Can anyone tell me how to solve this? Assume you have a vehicle tracking records from Oct.1 to Dec. 31 with wind speed information. All data is ...
2
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1answer
140 views

How to best execute the same query on many different vector layers?

I have some vector layers in my project and I need to separate the polygones by area (I need a copy of all shapes > 2ha). I know how to do this for each separate layer (query) but is the a tool to do ...
5
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2answers
1k views

How do I use QGIS python console to iterate through simple layer queries and png outputs?

I'm really new to QGIS coding and I'm having a hard time finding (especially) the api classes/functions to carry out actions of the Query Builder window. I'm basically trying to do this: Iterate ...
3
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1answer
211 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
585 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
698 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
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1answer
838 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 ...
12
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3answers
3k 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
474 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
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1answer
590 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
202 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
740 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
383 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
900 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
152 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
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0answers
355 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
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1answer
306 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
622 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
150 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.