Lessons Learned from Experiments with PostGIS Eleanor Tutt St. Louis

What is PostGIS? Eleanor Tutt | Lessons Learned from Experiments with PostGIS Providence NNIP Meeting | September 2012 Free and Open Source Adds support for geographic objects to PostgreSQL database (which is also open source)

Why Experiment ?? Eleanor Tutt | Lessons Learned from Experiments with PostGIS Providence NNIP Meeting | September 2012 Growing quantity of data Increasingly complex analysis needs Tired of seeing this in ESRI help files:

Continued Concerns Eleanor Tutt | Lessons Learned from Experiments with PostGIS Providence NNIP Meeting | September 2012 Other priorities besides shuffling data Fear of reliance on a lesser-known platform Skills Identified on LinkedIn Profiles 3,000 61, ,000

The experiment so far… Eleanor Tutt | Lessons Learned from Experiments with PostGIS Providence NNIP Meeting | September 2012

Frustrating - Projections Eleanor Tutt | Lessons Learned from Experiments with PostGIS Providence NNIP Meeting | September 2012 Need SRID to properly import data (and if you forget, you don’t get a warning)

Frustrating - Projections Eleanor Tutt | Lessons Learned from Experiments with PostGIS Providence NNIP Meeting | September 2012 SRID has to be in “spatial_ref_sys” table (and not all codes are there by default) Where’s my SRID???

Frustrating – Projections Eleanor Tutt | Lessons Learned from Experiments with PostGIS Providence NNIP Meeting | September 2012 No “on the fly” projection – must be constantly aware of SRID and use ST_Transform any time SRIDs don’t match

Exciting – Increased Speed Eleanor Tutt | Lessons Learned from Experiments with PostGIS Providence NNIP Meeting | September 2012 ArcGIS takes up to 45 seconds to get past the splash screen (let alone adding data)… …when half the time, my queries are simple and don’t require a “pretty map” (“Which bus routes are within a half mile of a site?”)

Exciting – New Analysis Capabilities Eleanor Tutt | Lessons Learned from Experiments with PostGIS Providence NNIP Meeting | September 2012 Drive time polygons/routings Converting polygons to lines/splitting lines into line segments So much more…

Exciting – ESRI + PostGIS! Eleanor Tutt | Lessons Learned from Experiments with PostGIS Providence NNIP Meeting | September 2012

ArcMap Query Layers + PostGIS Eleanor Tutt | Lessons Learned from Experiments with PostGIS Providence NNIP Meeting | September 2012

Side Benefits – Better Understanding of ArcGIS Eleanor Tutt | Lessons Learned from Experiments with PostGIS Providence NNIP Meeting | September 2012 Learning a different language helps you think in different ways What is intuitive in one system may be possible, but easy to miss, in the other

Side Benefits – Opportunity for “Data Audit” Eleanor Tutt | Lessons Learned from Experiments with PostGIS Providence NNIP Meeting | September 2012 “Export_Output_2.shp” “test_data.shp” “RHCDA shp”

Conclusions??? Eleanor Tutt | Lessons Learned from Experiments with PostGIS Providence NNIP Meeting | September 2012 Dealing with projections is incredibly frustrating – especially with data from two states Learning curve is steep, but climb-able We aren’t ready to leave ArcGIS, yet