3,854 reputation
33280
bio website elegantdesigns.ca
location Fredericton, Canada
age 32
visits member for 4 years, 3 months
seen 2 hours ago
GIS, Transportation, Civil Engineer in New Brunswick Canada. I'm interested in using FOSS, python, QGIS, PostGIS, GRASS, and QT to develop open source engineering applications

Nov
24
revised Free GIS workshops, tutorials, and applied learning material
added 765 characters in body
Nov
24
revised Free GIS workshops, tutorials, and applied learning material
added 134 characters in body
Nov
24
comment Free GIS workshops, tutorials, and applied learning material
@radek I was thinking more along the lines of existing documentation that individuals can download and do on their own free time. But if it's forthcoming and the material will be available for download later then I see no issue with that.
Nov
24
asked Free GIS workshops, tutorials, and applied learning material
Nov
23
comment How to sum area of polygons by values occuring in multiple fields?
using an ORM like geoalchemy, how would you build the same query? I know it's a follow up question, but I think it's somewhat related to the OP's
Nov
23
revised Method to shade or overlay a raster map to reflect time of day and ambient light
edited title
Nov
23
comment Vehicle travel data for the USA
I was wondering, were you able to get the data you needed?
Nov
23
revised Method to shade or overlay a raster map to reflect time of day and ambient light
added 392 characters in body
Nov
23
asked Method to shade or overlay a raster map to reflect time of day and ambient light
Nov
20
answered Advice for someone considering careers in GIS?
Nov
19
comment Dealing with bridges and tunnels when modeling raster least cost paths?
@julie - WRT (1) As long as the peds are not trespassing, you might not want to build a model that encourages cross cutting even if it is the existing scenario. (2) There is prob. a way to grab centerlines from gaps in a polygon layer (new question?). Modelling wise, I would use regular road data and remove the edges with no sidewalks. I'll add trail data and manually trace whatever doesn't exist. Where roads and trails meet I'd create dummy nodes. The model would favours trails, roads, roads with no sidewalk, and then raster based data such that the route doesn't infringe anyone's property.
Nov
18
comment How to union polygons with common ID in QGIS?
A follow up question; how do you ensure that the boundaries matchup nicely after the dissolve? from experience, I find that I have to go back and remove or redissolve polygons
Nov
18
comment How to union polygons with common ID in QGIS?
I realize you're new to this site and thanks for posting the question; however, the posts are reserved usually for answers, any thanks or additional information could be added to the original posts. Specific comments to a post could be added under each post. Don't forget to accept an answer if it works for you, and feel free to update your question or ask the users for more clarification. Cheers :)
Nov
18
revised How to union polygons with common ID in QGIS?
Fixed up the formatting but I did not correct grammar or spelling.
Nov
15
comment How can I optimize pgrouting for speed?
Just curious have you looked at any Mode choice models? We use the centroids to build slimmed down version of the network, and then we optimize reroute based on it. Mind you, we use this exercise in planning and predicting traffic rather than in operations
Nov
15
comment How can I optimize pgrouting for speed?
Another option would be to build an O/D matrix (origin/destination matrix). This is a technique we use in traffic engineering. split the network into zones, so let's say a large city could have 100 zones. Each zone would have a dummy centroid. Connect the centroid to your network via a dummy link. Then you can remodel your whole network as 100 x 100 trips (10,000 trips in total). When a user does a search, pgrouting has to find a route closed to the centroid or dummy link on the origin and destination side.
Nov
15
comment How can I optimize pgrouting for speed?
I'm not a pgrouting expert, but can you cache results, for example, if you know a common sub route is always used, can you precache it? therefore, you have to do less searches? Also, van you limit searches to Arterials and collectors?
Nov
14
comment Which is the best way to create a polygon with the extents of a raster file in QGIS?
I think this is a better example from the pyqgis cookbook. If you get the extents, you can use this to create the vector bound
Nov
14
comment Which is the best way to create a polygon with the extents of a raster file in QGIS?
I'm not versed with the QGIS API, but would this help?
Nov
13
comment Nearest Neighbor Grouped Selection in QGIS
@whuber this is awesome