12,152 reputation
1065148
bio website maphew.com
location Yukon Territory, Canada
age
visits member for 4 years, 5 months
seen 13 hours ago

hewer of maps, old time techie, newbie developer

woohoo, http://gis.stackexchange.com/ now open to the public!

personal - www.maphew.com
in-between - yukongis.ca
work - www.environmentyukon.ca

profile for matt wilkie on Stack Exchange, a network of free, community-driven Q&A sites


Oct
20
comment How to preserve the original direction of NHD segments when creating a route using the gp.CreateRoutes_lr tool?
Hi Justin, welcome to our site :) Please expand an on your answer, perhaps with an example. We try to avoid 1 line answers as they usually don't stand the test of time. We want to build a knowledge base that will be relevant for as long as possible.
Oct
20
comment RuntimeError while executing python
Welcome to GIS Stack Exchange :) Use the [edited x time ago] link above to see how I reformatted your answer so the list displays properly. Another improvement is to go beyond bare recipe, try and educate. Something more along the lines of "The error message indicates the wrong version of ___ is installed or can't be located. Try installing the latest from ___ from www.___. For example:...."
Oct
3
comment How to smooth/generalize a polygon in qgis
Nice demonstration of the buffer/de-buffer approach at Paul Ramsey: Removing Complexities
Oct
3
comment Update point coordinates in QGIS after manually moving locations in edit mode
+1 for note about saving to a new format. I was spinning my wheels trying to figure out why the tool was disabled for my GPX layer; save to shape and it's all good. (but -1 because as useful as this answer is, it doesn't answer the question asked: modify location based on attribute value)
Oct
3
comment Update point coordinates in QGIS after manually moving locations in edit mode
see gis.stackexchange.com/q/63114/108 for moving coords by typing new numbers, though this is a one-by-one operation and doesn't answer the question asked
Oct
1
comment Using Label classes vs Definition queries - which performs the best?
Yes, please test (and report back if you can). I also lean to definition queries, but for usability performance reasons. The label expression dialogs are painfully sluggish and several click layers deeper than the def query ones. They're also easier to get at in python.
Oct
1
comment Using Label classes vs Definition queries - which performs the best?
I think your math is mistaken. There is the same number of queries on either case, the Q is is there a performance difference dependent on where the query is placed? (Definition Query or Label Expression)
Sep
29
comment How to account for Colour Blindness when designing maps?
excellent news, thank you!
Sep
17
comment What is the difference between Coverage, Shapefiles and Geodatabases in ArcGIS?
Daniel Morisette reverse engineered enough of the coverage format to be useful, its now part of the GDAL/OGR suite. avce00.maptools.org/docs/v7_bin_cover.html
Sep
5
comment Convert DEM to STL (3D Printer Format)
the 2nd link has succumbed to bit rot, the domain name is/was "www.surfacemodeling.com", the tool "Import Points 2" and cost ~$100 in 2005. Likely completely dead now.
Aug
28
comment Raster diff: how to check if images have identical values?
Yes the images we want to do something about are classified, but part of the point of a diff test is to weed out intermingled images that aren't and shouldn't be classified (leave them out of the conversion).
Aug
27
comment Raster diff: how to check if images have identical values?
@whuber thanks for ensuring proper NoData handling stays in the conversation.
Aug
27
comment Raster diff: how to check if images have identical values?
@radouxju the images range up to 100,000px to a side, so ~30GB uncompressed. We don't have machine with that much ram (though perhaps with virtual...)
Aug
27
comment Raster diff: how to check if images have identical values?
intriguing, I love gdal, didn't know about this script. Docs for interpreting the results are sparse to non-existent though ;-). In my initial testing it reports differences in colour interpretation and pallettes, meaning it might too specific for my current needs. I'm still exploring it though. (note: this answer too short to be a good fit here, link only answers are discouraged, please consider fleshing it out).
Aug
21
comment How to generate automatically the name of output parameters in a python script tool?
there isn't enough detail in your Q for us to help. Perhaps include a sample of your script, reduced to it's simplest possible form (sometimes pseudo code can be clearer than the real thing). Also What GP tool do you see creating a workspace automatically? (most ask for a pre-existing workspace). ...and finally a tip: add the GP tool to a model, then export as python script. That will show you how the tool does it. (And if that works, come back and answer your own question so others can benefit from your research)
Jul
4
comment Setting symbol descriptions of ArcMap layout legends from table?
I solved the problem of having to make descriptions and lookup codes match, see my answer.
Jun
25
comment Recommended ArcGIS Server and RDBMS layout on these two machines?
yes @Vince, by the numbers new hotness has lower CPU megahertz, but the chip is several generations newer and has on board cache and some other stuff I don't understand. I was unable to find a (clear) report which could tell me which is in fact faster in the real world. The physical drives are slower, but the backplane is faster; I dunno what the limiting factor is/are. RAM is a bit of a canard, since it's the easiest and cheapest thing to attack (if we find ourselves constrained there we can change it quickly).
Jun
25
comment Find polygons that contain a specific number of points
There isn't a 1 step solution, combine gis.stackexchange.com/questions/58485/… with Branco's answer below.
Jun
25
comment Find polygons that contain a specific number of points
right idea, but can be even simpler: Spatial Join creates a field automatically called Join_Count, which is the number of times the Join Features (the points) intersect the Target Features (the polygons). (NB: other relationships besides /intersect/ can be used.). Also, you don't need to export, just use a Definition Query on the Spatial Join result to select only Join_Count > 30; see Displaying a subset of features in a layer
Jun
24
comment Setting symbol descriptions of ArcMap layout legends from table?
An interesting idea that might work in some situations. It won't work here though because the description table is just a table, there is no geometry. One could join the geometry and descriptions, but I'm not interested in that extra work or performance hit for this project.