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...
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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...
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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...
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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...
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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...
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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...
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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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