rpsgroup.com/ rpsgroup.com/ rpsgroup.com/ rpsgroup.com/uk uk uk uk PostGIS: three out of four ain’t bad Chris Hill 05 May 2015 A slide from 11 years ago… A slide from 11 years ago… A slide from 11 years ago… A slide from 11 years ago… PostgreSQL/ PostgreSQL/ PostgreSQL/ PostgreSQL/PostGIS PostGIS PostGIS PostGIS ✓ It’s a relational database ✓ We’ll look at this… ✘ Use QGIS or st_astext() ✓ We’ll look at this too… W W Why you should use hy you should use hy you should use hy you should use PostGIS PostGIS PostGIS PostGIS over a desktop GIS over a desktop GIS over a desktop GIS over a desktop GIS • Spatial and attribute querying together • Permits advanced joins • Aggregate (group by) functions • Transcript of all work done • Scripting in SQL – Repeatability – Enforced documenting of processes • Good raster/vector integration • Can link to R, Python, QGIS… Will it take longer than a desktop GIS? – Possibly, if you only do something once
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Chris Hill RPS Postgis threeoutoffouraintbad 20150505
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WWWWhy you should use hy you should use hy you should use hy you should use PostGISPostGISPostGISPostGIS over a desktop GISover a desktop GISover a desktop GISover a desktop GIS
• Spatial and attribute querying together
• Permits advanced joins
• Aggregate (group by) functions
• Transcript of all work done
• Scripting in SQL
– Repeatability
– Enforced documenting of processes
• Good raster/vector integration
• Can link to R, Python, QGIS…
Will it take longer than a desktop GIS?
– Possibly, if you only do something once
st_intersects 703
st_transform 461
st_union 454
st_length 435
st_buffer 386
st_area 362
st_centroid 307
st_setsrid 280
st_y 257
st_startpoint 255
st_x 244
st_endpoint 232
st_makevalid 225
st_buildarea 212
st_dump 198
st_intersection 180
st_collect 176
st_azimuth 168
st_makeline 143
st_makepoint 121
Analysis functions
Management functions
My top 20 My top 20 My top 20 My top 20 PostGISPostGISPostGISPostGIS functionsfunctionsfunctionsfunctions Fuzzy polygon matching 1Fuzzy polygon matching 1Fuzzy polygon matching 1Fuzzy polygon matching 1
Perhaps use the logic of all three options?Perhaps use the logic of all three options?Perhaps use the logic of all three options?Perhaps use the logic of all three options?
Homework: to make the rays you might use…Homework: to make the rays you might use…Homework: to make the rays you might use…Homework: to make the rays you might use…