2,563 reputation
620
bio website github.com/jlaura
location Flagstaff, AZ
age 31
visits member for 3 years, 3 months
seen 9 hours ago

I am a geography Ph.D. student at Arizona State University, with interests in FOSS, big data, spatial algorithm implementation in python, visualization, the application of cartographic techniques / spatial analysis to planetary data (Moon, Mars, Titan, etc.), and remote sensing.

My primary research focuses are in the geocomputation domain.


Oct
26
comment How can I create random concave polygons for test purposes?
@whuber A sample dataset consisting of just convex polygons does not simulate the convex / concave reality that one sees in applications such as congressional redistricting - this discount multipart polygons and islands (in the sense that the unit has not neighbor, not just in the case of a physical island). Additionally, a generated dataset provides the means for a priori knowledge of the optimal solution. Can you suggest any references to the perturbation method? It sounds as if this will simply introduce slivers at common edges (fixed endpoints with each edge defined by only two points).
Oct
26
revised How can I create random concave polygons for test purposes?
added 1077 characters in body
Oct
26
asked How can I create random concave polygons for test purposes?
Sep
14
answered How to average a set of n rasters using gdal or other GRASS module?
Sep
9
answered Where download sld styles for OpenStreetMap for GeoServer?
Sep
9
comment Is it possible to destroy a spatial index?
Updated with additional code. Added a comment wondering why intersections are indexed by negative long.
Sep
8
revised Is it possible to destroy a spatial index?
added 564 characters in body
Sep
8
comment Is it possible to destroy a spatial index?
Exactly my thought. I thought that perhaps it was because the variable was not going out of scope, but that does not appear to be the issue. As you said, calling soat_index again should force it to reinitialize.
Sep
8
comment Is it possible to destroy a spatial index?
Code / Pseudocode added. I can flesh in some more if needed, but these are the important parts.
Sep
8
revised Is it possible to destroy a spatial index?
added 1298 characters in body
Sep
8
comment Is it possible to destroy a spatial index?
Yes. In init() I loop through an input point layer to generate a polyline layer. The spatial index is off the poyline layer. Then split, update the point layer attribution, recreate the polyline layer. It is on the recreate that the spatial index is duplicated. I tried both reinstantiating QgsSpatialIndex and emptying it out with deleteFeature. No joy on either. I see that the API has a ~QgsSpatialIndex (destructor), but I don't think it is accessible via python.
Sep
8
comment Is it possible to destroy a spatial index?
This is within a plugin, on an in-memory layer, so the spatial index should only be created in memory.
Sep
8
asked Is it possible to destroy a spatial index?
Aug
28
comment Qgis 1.9 commitChanges() and Redraw a temporary layer
Got it. This fails on a view, but propagates on a table. Also not sure why geojson write was failing. I'll investigate. Not sure if this is of value to write up to help someone else or too specific. Thanks for the info / questions.
Aug
28
comment Qgis 1.9 commitChanges() and Redraw a temporary layer
The 'source' dataset is a postgis table. This is what is edited. On load, I use it to derive my in memory layer. I then edit the source, remove the in memory layer, and then rebuild the in memory layer. On rebuild, I am not able to capture the edits to the source, even if I commit them. Is this the expected behavior?
Aug
27
comment Qgis 1.9 commitChanges() and Redraw a temporary layer
Derived in that it is generated from the layer that is being edited.
Aug
27
asked Qgis 1.9 commitChanges() and Redraw a temporary layer
Aug
22
comment What is topojson and how is it different than geojson?
re: support - It looks like the community is starting to add topojson support, presumably because of the 'weight' of geojson over a small pipe. PostGIS2.1 (Aug 2013 release) support a From_TopoJson and the topojson team has a reader that integrates with D3. Support from these two larger players is, I believe, a great thing for keeping TopoJson around.
Aug
16
accepted ArcGIS Symbology Transparency
Aug
16
comment QGIS Extend Toolbar (GUI) Button Functionality via Python Plugin?
Awesome. Thanks!