Acronym for Structured Query Language. A syntax for retrieving and manipulating data from a relational database.
22
votes
9answers
9k views
How can I connect to a PostGIS database from ArcMap 9.3 and 10.0?
How can I connect to a PostGIS database from ArcMap 9.3 or 10.0?
Ideally, I would like to be able to perform spatially enabled queries and receive the results back (e.g. spatial and non-spatial ...
17
votes
2answers
1k 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 ...
4
votes
3answers
923 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.
...
2
votes
2answers
458 views
ArcObjects: Alternative workflow to using a SQL query with over 1000 values in IN statement
I have a ListBox listing the unique values of a column in a feature class; the user can select any number of values and click a button to then zoom to the set of features matching those values. A ...
8
votes
5answers
2k views
A SQL console in QGIS
I know QGIS comes with its field calculator, which is not bad. It also comes with ftools which permits several operations on geometry and attributes. But we often need more control and I haven't seen ...
10
votes
3answers
854 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 ...
3
votes
3answers
338 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
...
1
vote
1answer
77 views
Raster as Attribute Field Error
I'm using Arc 10.1. I am creating a parcel inventory where I would like to have a photo of the property attached as an attribute and view-able with an HTML popup. I have a polygon feature class built ...
1
vote
1answer
57 views
Why does this SQL syntax produce empty feature class with ArcGIS Select_analysis?
I'm working on a script that involves an arcpy.select_analysis function. The problem I have is that when I run the script it produces an empty file. I've verified that the whole thing works when in ...
1
vote
1answer
624 views
Labeling classes for small roads on large extent maps in arcmap with sql statement
I have many small sub divisions that won't label nice, (lot of overlapping) unreadable. While using the bullet leader symbol. What would be the best statement that would place the labels in a clear ...
0
votes
0answers
108 views
How to find points, sort them based on closeness, and get 1-20, 21-40, etc. Efficiently using Myisam and mysql
Note: In this question I want actual mysql command that I should send. Not concept, and stuff.
This question is similar with how to find 20 closest points efficiently
However in that question I ...
13
votes
1answer
579 views
Identifying topological relationships using PostGIS
I'm trying to perform a basic typology analysis using PostGIS. My objective is to find any polygons that touch other polygons. To do this, I thought the ST_GetFaceEdges would work
(reference). I want ...
11
votes
1answer
410 views
Nearest Neighbor Grouped Selection in QGIS
OK - so I have an interesting problem I am trying to solve. I have a list containing over 100,000 points in lat/long format which I have imported into qgis.
Now, what I am trying to do here is group ...
8
votes
4answers
925 views
Queries returning very big datasets in PostGIS
I have a PostGIS query that will return several million rows:
SELECT
t1.id AS id1,
t2.id AS id2,
ABS(t1.mean_h - t2.mean_h) AS h_diff,
ST_Distance(t1.the_geom, t2.the_geom) AS dist
FROM ...
7
votes
1answer
576 views
PostGIS Intersection and Summarise Attributes
I am usually an ArcGIS desktop user, but keen to start using PostGIS more and I have a really big bit of processing to do. Not sure what functions to use, hopefully someone can help.
I have a polygon ...
6
votes
2answers
629 views
Join intersecting lines with PostGIS
This is something that I'm almost ashamed to ask but I can't seem to get it to work for the life of me.
I have a road layer with segments, each segment has a Road ID and a segment type.
I would like ...
5
votes
3answers
2k views
ST_Intersection slow query
I am trying to perform an intersection between two layers:
Polyline layer representing some roads (~5500 rows)
Polygon layer representing irregularly shaped buffers around various points of interest ...
4
votes
2answers
3k 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 ...
8
votes
3answers
965 views
Beginner PostGIS question: getting geometry from multiple tables
I am very new to PostGIS, PostgreSQL, and SQL in general.
I have 44 tables in my PostGIS database, and each one represents a different layer of vector data. Each was loaded from a separate shapefile, ...
6
votes
1answer
743 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 ...
6
votes
1answer
522 views
Spatial joins in OGR SQL
I have seen that OGR supports it's own form of SQL, I was wondering if it's possible to do spatial joins.
Something like select all objects where one intersects the other. I did have a look around ...
6
votes
2answers
2k views
Creating spatial tables with PostGIS
In the PostGIS documentation it says that there are two steps to creating a spatial table with SQL:
Create a normal non-spatial table.
Add a spatial column to the table using the OpenGIS ...
6
votes
2answers
2k views
SELECT TOP query in ArcGIS
Is there a way to use a SELECT TOP (n) within ArcGIS desktop? Is appears that since the ArcGIS query builder is effectively building the SQL statement after the WHERE clause, that this may not be ...
5
votes
1answer
145 views
How to Comment Out Definition Queries
I use Definition Queries a lot in my daily GIS life, but one of the many things I've found annoying about ArcMap is the inability to comment out Definition Queries. I'd like to have this option as ...
5
votes
1answer
174 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 ...
7
votes
0answers
64 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 ...
5
votes
1answer
272 views
How to filter points based on proximity while inserting into PostGIS?
I have a large amount of locations that need to be inserted to a PostGIS database. However, I'd like to aggregate these points so that if there's already a location, say nearer than a kilometer, then ...
5
votes
3answers
2k views
Is there a way to label points in a regular interval in ArcGIS 10? [SOLVED]
Estou trabalhando com linhas em estradas representadas por uma grande grande quantidade de pontos em sequencia.
Uma vez que colocar o nome de todos os pontos tornaria a identificação impossível, ...
4
votes
1answer
718 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 ...
3
votes
2answers
467 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 ...
3
votes
2answers
1k views
Bounding box for PostGIS table
Is there an easy way to get the bounding box for an entire table in PostGIS?
Thanks
3
votes
2answers
829 views
How to write a SQL WHERE Clause using Multiple Choice values in FME?
I published a parameter which is of Choice Multiple type. I wish to
use values from this parameter for WHERE Clause when Reading Inputed
Data in the begin of Workbench.
So there is no problem if I ...
2
votes
1answer
77 views
Select by attribute expression invalid in python
I'm not sure how my expression is failing. Any ideas?
inPoints = "points.shp"
i = 0
arcpy.MakeFeatureLayer_management(inPoints, "pts")
arcpy.SelectLayerByAttribute_management("pts", "NEW_SELECTION", ...
2
votes
1answer
57 views
ArcGIS 10: How to populate SQL options for parameter in tool
I'm trying to create a tool where individuals can select a variety of records using a SQL expression that is then passed to a calculation. I can add a parameter under the tool, and select SQL ...
1
vote
1answer
266 views
Creating a SQL query in the 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 ...
