6,764 reputation
244133
bio website djq.me
location Dublin, Ireland
age
visits member for 3 years, 10 months
seen 2 days ago

interested in postgis, geodjango, qgis, python, R and LaTeX.

twitter: @djq


Jan
24
comment How to join data from a CSV to a shapefile using QGIS
Hi @user14519, if you upload images to imgur.com and paste the link someone can insert them in your question. I would check that the data type in each file matches (e.g. numbers or characters in both). This can be a common reason why joins fail.
Jan
22
comment How Can I Make QGIS Stop Blinking Every Time I Pan?
It's not ideal, but you can turn off rendering by ticking the render box on the bottom toolbar. This means that data outside the current viewport is no longer shown/refreshed, though.
Jan
15
comment Trying to combine nearby points into a polygon
There's a great answer to another question on the site which explains how to use kmeans clustering to identify groups. gis.stackexchange.com/a/11778/803 I've used this approach and found it quick on thousands of points; not sure what it would be like on millions.
Jan
15
comment How to make working with Postgis vector layers in QGIS faster?
In the connection options, I usually tick the box Use estimated table metadata which makes it quicker to choose the layers. I don't think this affects panning though.
Jan
10
comment Converting polygon values to a vector grid using PostGIS
I forgot to say, it does return this warning message when running NOTICE: geometry_gist_joinsel called with incorrect join type. I can't tell if this is a significant or not.
Jan
10
comment Add Attribute and merge .shp's from multiple folders/directories
Hi - Are using ArcGIS? You could add the ArcGIS tag and perhaps python to your question.
Jan
10
comment PostgreSql query problem with aggregate functions
Just added a way of doing it in one step.
Jan
10
comment Converting polygon values to a vector grid using PostGIS
That works perfectly, thanks. I grouped by gid and geom. I'm trying to understand the logic behind the LEFT JOIN poly p ON ST_Intersects(g.geom, p.geom) though. Is it like a true/false condition for relating the geometries?
Jan
10
comment Converting polygon values to a vector grid using PostGIS
hmm, interesting. I've done this before using rasters, but I feel like the vector-intersection approach is more accurate. I feel like a vector 'gridfying' function could be a worthy endeavor.
Jan
8
comment How do I create multiple polylines from single polyline that consists of disjunct sections?
Can you describe what software and version you are using to do this, and perhaps link to a diagram of what you are doing?
Jan
1
comment Easiest way to create measured intervals between shape points
What software would you like to do this in?
Dec
28
comment Nearest Neighbor problem in Postgis 2.0 using GIST Index (<-> function)
I assume that using ST_DWithin() is not relevant in this case? Also I don't know if it would make any difference but perhaps you could use SELECT .... LIMIT 1 on your second query instead of SELECT DISTINCT ON
Dec
26
comment Where can I download the Google Road network as shapefile?
An answer here: spatiallyadjusted.com/2012/12/26/…
Dec
20
comment How to colour polygons with a completely transparent fill using MapServer?
Thanks for your answer - is the SLD for geoserver related at all? I don't see the similarity between it and MapServer.
Dec
15
comment How to colour polygons with a completely transparent fill using MapServer?
Just added an image to explain what I mean.
Dec
15
comment Which Geo stack for an online strategic wargame?
OpenLayers might be another JavaScript library to consider as part of the workflow.
Dec
15
comment How to colour polygons with a completely transparent fill using MapServer?
Sorry for the double confusion; just clear polygon fill; lines do not matter.
Dec
14
comment How to colour polygons with a completely transparent fill using MapServer?
I don't mind if the lines appear or not; I just want a clear polygon fill.
Dec
14
comment How to colour polygons with a completely transparent fill using MapServer?
how could I have no-fill of the polygon that way?
Dec
14
comment How to colour polygons with a completely transparent fill using MapServer?
Did this result in a completely transparent polygon? I tried experimenting with values of TRANSPARENCY from 0 - 100 and it seemed to just adjust the opacity. I realize this was not clear in my question intially - I revised it.