artlemboSep 18, 20191 minVirtual layers with QGIS – wait a second, this is starting to look like Manifold…If you are like me, you love writing spatial SQL. But what can you do if you have a geodatabase, some shapefiles, or any other data format? Well, you can a...
artlemboJul 7, 20182 minFinding “Dangles” with PostGISDo 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 line segment. Now,...
artlemboJun 22, 20181 minMulti-Ring (non-overlapping) Buffers with PostGISI 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 had concentric buffe...
artlemboJun 19, 20181 minGIS Analysis of Overlapping LayersSure you can solve it with a few for loops, inserting the results into a new table, but that really is a hassle. Also, I have to do it for different distan...
artlemboNov 21, 20171 minBig Data GeoAnalytics – Turning Points to LinesIn my last video, I gave a short of mile-high view of how SQL can be used for big data geoanalytics. I want to dive a little deeper, and explore the idea of...
artlemboNov 20, 20171 minBig data geo-analytics with SQLI’m getting ready to create a course in big data analytics with GIS. I have lots of ideas as to what to do, but one thing I know is that I will be using spa...
artlemboMar 26, 20172 minMaryland State GIS Conference (TuGIS)The TuGIS training workshop on March 20, 2017 is completed – you can see the workshop evaluations below: The workshop evaluations are in (if you want to cut ...
artlemboJan 27, 20172 minWorkshops at the Maryland Geospatial Conference#TUgis2017) is on March 20/21, 2017. I first attended TUgis in 1990, and it is always a great conference. It is not too large, so it is great way to have ...
artlemboDec 18, 20164 minUndergraduate Geospatial Python ProjectsGIS Programming students presented their programming projects to ESRI. First, I cannot say enough to thank ESRI for taking time out of their schedule to meet...
artlemboApr 26, 20163 mink-Nearest Neighbor with PostGRESWell, even though you didn’t ask for it, I decided to create a k-nearest neighbor analysis in PostGRES/PostGIS. This has lots of potential: find the 5 neare...
artlemboApr 26, 20162 mink-nearest neighbor with SQL in Radian StudioI wanted to give you another look at some features that Radian Studio will offer. I’ve shown how we can use SQL to replicate the ARC/INFO NEAR function, and ...
artlemboApr 20, 20164 minTrade Area Analysis in Postgres / PostGISHow 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 to perform trade ar...
artlemboJun 26, 20151 minNew Books – How do I do that in PostGIS, How do I do that in Manifold SQLI 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 PostGIS: For those w...
artlemboJun 9, 20142 minSpatial is Not Special – Quadrat AnalysisIn our book we illustrated the use of quadrat analysis for determining whether points were random, clustered, or distributed. Figure 14.9 from the book show...
artlemboMay 30, 20142 minSpatial is Not Special – Nearest Neighbor IndexIt is nice to get back to the book, and start talking about Statistical Problem Solving in Geography again. Today we are going to look at the Nearest Neighb...
artlemboMay 28, 20142 minARC/INFO Functions in SQL – Line DensityDale posted a request to see Line Density recreated in SQL. Please take a look at the ESRI help topic for line density. I will warn you, the SQL for this is...
artlemboMay 26, 20141 minARC/INFO Functions – Symmetrical DifferenceI was recently asked by danb to illustrate the ARC/INFO function symmetrical difference. We basically want to find those areas in layer A that don’t intersec...
artlemboMay 23, 20142 minARC/INFO Functions – UNIONWe are going to conclude our overlay posts with the ARC/INFO UNION command. This should be a lot easier than it actually is. I think the problem is that Ma...
artlemboMay 21, 20142 minARC/INFO Functions in SQL – IDENTITYThe ARC/INFO IDENTITY operation seen here is sometimes confusing because it takes ALL of the Input feature, and the part of the IDENTITY feature that interse...
artlemboMay 14, 20141 minSpatial is Not Special – Spatial Interaction completionWe’ve spent some time looking at how to create spatial interaction models using PIVOT tables and spatial constructs in SQL. The one last thing I wanted to a...