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artlembo
Mar 14, 20193 min read
Easy bivariate map with Postgres
A friend recently asked me about the cool looking bivariate maps produced with ArcOnline, lamenting that the capability seemed lacking...
234 views1 comment
artlembo
Feb 21, 20192 min read
Engaging students with multiuser editing, and FOSS4g
A friend is doing some research on estrogen and estrodial in water samples in Delaware. We have about 50 sub-watersheds that show the...
24 views0 comments
artlembo
Oct 16, 20185 min read
Big Data Results
I wanted to revisit the taxi data example that I previously blogged about. I had a 6GB file of 16 million taxi pickup locations and 260...
150 views0 comments
artlembo
Jul 7, 20182 min read
Finding “Dangles” with PostGIS
Do you have a set of lines that you need to determine if there are any “dangle” nodes? A dangle is a line segment that overhangs another...
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artlembo
Jun 22, 20181 min read
Multi-Ring (non-overlapping) Buffers with PostGIS
I was interested in creating mult-ring buffers but with a twist: I didn’t want the buffers to overlap one another. In other words, if I...
270 views0 comments
artlembo
Dec 17, 20164 min read
Undergraduate Geospatial Python Projects
GIS Programming students presented their programming projects to ESRI. First, I cannot say enough to thank ESRI for taking time out of...
280 views0 comments
artlembo
May 26, 20162 min read
Advanced Editing Capabilities with PostGIS
CLICK TO VIEW Jeff Scarmazzi presenting on h0w to create editing rules and triggers using Postgres and PostGIS Today I want to introduce...
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artlembo
May 18, 20163 min read
Open Source GIS Course at UMD – the Syllabus
UMD provided me with enrollment numbers, and we are getting a pretty full class. However, a few people on the “outside” have asked for a...
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artlembo
Apr 26, 20163 min read
k-Nearest Neighbor with PostGRES
Well, even though you didn’t ask for it, I decided to create a k-nearest neighbor analysis in PostGRES/PostGIS. This has lots of...
221 views0 comments
artlembo
Apr 20, 20164 min read
Trade Area Analysis in Postgres / PostGIS
How I used SQL to generate an accumulated sum of spatial data My friend Tomas does work with business analytics, and wanted to find a way...
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artlembo
Apr 19, 20162 min read
SQL and ogr to create 4D lines
A friend recently asked me to help him generate polyline shapefiles with Z and M values that he could deliver to a customer. The problem...
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artlembo
Jul 7, 20152 min read
When More is Less…. lessons from processing large data files
My good friend Stuart Hamilton gave me a fun conundrum to try out. He has a file of province boundaries (400 areas) and lidar derived...
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artlembo
Jun 26, 20151 min read
New Books – How do I do that in PostGIS, How do I do that in Manifold SQL
I have two new books out – How do I do that in PostGIS, and How do I do that in Manifold SQL. From the back cover of How do I do that in...
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artlembo
Apr 20, 20154 min read
A Poor Man’s Parallel Processor for GIS
In addition to SQL, I also am interested in processing large volumes of spatial data. One of the newest rages in “big data” is Hadoop....
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