Ow, That Stings!

There’s a certain backhanded snarkiness to the ESRI UC Q&A item on PostGIS:

Will ESRI support the PostGIS open-source spatial extension for PostgreSQL?

Yes, ESRI will provide our customers with the option of using either the ISO/OGC spatial type or the PostGIS spatial extension.

So they’ll support the standard type or that PostGIS thingymabob. Of course, PostGIS is also an ISO/OGC spatial type, but somehow that fact is a little submerged in the phraseology.

Perverse Incentives

I am sure others have beaten this horse before, but I just have to take a whack at it.

Oracle, ESRI and others license their server-side technology on the basis of dollars-per-processing-unit, usually in the form of Constant * NumberOfCores * Price. For example, the base price for Oracle Enterprise (which you need to do high-end processing, like, say, computing a buffer (snort)) is 0.5 * NumberOfCore * $40,000.

OK, time for the quiz-show section of our show: Let’s say you buy yourself some Oracle, and start using it. You find a particular use case that is slow, but important to you. You call up your Oracle representative, what will his answer be: (a) we’ll make it faster or (b) you need more processing power. Remember, this is not a trick question, and he does earn commissions on sales.

Take it up a level. From a strategic financial point of view, all R&D dollars spent on on performance improvements actually constitute a double cost: the cost of doing the development; and, the cost of lost revenue due to fewer upgrades. If I am the CEO, do I encourage my managers to spend money on performance tweaks, which will reduce upgrade revenue, or on new features, which will drive new sales?

Safari: SyntaxError - Parse error

I have now worked my way past this particularly opaque Safari error message twice, which is one time too many, so I am putting the explanation for my error case online. Safari seems to have a few cases where it throws up this utterly useless error message. It does include a line number reference, and double-clicking the error line in the log will take you to the offending line, but heaven help you if it is not clear what is wrong at that point.

I found another reference to this problem on the web, but it wasn’t the problem I had.

My problem was that I used “abstract” as a variable name. Because I am working on web pages for viewing presentation abstracts, this seemed natural, however I guess “abstract” is a reserved word of some kind in Safari’s Javascript implementation. Firefox showed no errors and happily ran code that Safari could not even parse.

Cognitive Dissonance

Try to hold these two concepts in my head at once… Ed Parsons, at the Open Street Map conference… Ed Parsons, at the Open Street Map conference… Ed Parsons, at the Open Street Map conference…

Just as in Hollywood, casting against type is sure to bring in the punters.


Ed Parsons, former CTO of the Ordnance Survey (organization dedicated to the monetization of proprietary data), current geospatial evangelist for Google (organization dedicated to the monetization of proprietary data), speaking to Open Street Map (organization dedicated to the free public domain data). Will there be a mud wrestling pit too?

Mass Shape File Load into PostGIS

I needed some test data to do some performance investigations, and had to load 235 shape files, all of identical schema. Here’s what I did.

First, get the table schema into the database, by loading a small file, and then deleting the data. We delete the data so we can loop through all the files later without worrying about duplicating the data from the initial file.

shp2pgsql -s 3005 -i -D lwssvict.shp lwss | psql mydatabase
psql -c "delete from lwss" mydatabase

Then use the shell to loop through all the shape files and append them into the table.

foreach f (*.shp)
foreach? shp2pgsql -s 3005 -i -D $f -a lwss | psql mydatabase

Note the “-a” switch to tell shp2pgsql we are in append mode, rather than the default create mode. Add a spatial index, and we’re done.

psql -c "create index lwss_gix on lwss using gist (the_geom)" mydatabase

Seven hundred thousand line segments, ready to play!

psql -c "select count(*) from lwss" mydatabase

(1 row)