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| bio | website | |
|---|---|---|
| location | ||
| age | ||
| visits | member for | 6 months |
| seen | May 11 at 8:26 | |
| stats | profile views | 3 |
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Mar 19 |
comment |
building larger polygons from smaller ones *without* a common id in PostGIS 2) I had not seen that post, and it would present a fairly straightforward solution. I guess the question would become how many polygons I could union at a time w/o my system falling over (I may need to do millions spread over a tens of thousands of kilometres). Perhaps way forward would be multi-step: first union/dump within tiles of a much larger-scale grid; then select any polygons that intersect borders of the grid into new table; then union/dump those; then combine all 'freestanding' polygons. |
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Mar 19 |
comment |
building larger polygons from smaller ones *without* a common id in PostGIS Devdatta -- cheers. 1) Yes, touching polygons should be dissolved so that ultimately no polygons touch. |
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Mar 19 |
asked | building larger polygons from smaller ones *without* a common id in PostGIS |
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Jan 22 |
comment |
Ordnance Survey TOIDS: converting from strings to integers I should have been more clear about saving 'space': I was mainly thinking about memory rather than storage. I have run a quick experiment on two tables, one with a single text column populated by 7.5m TOID records and the other with TOIDs converted to bigint. With an index on each, the bigint table was 55% the size of the text table (390Mb vs 707Mb) -- so a significant if not huge difference. |
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Jan 22 |
comment |
Ordnance Survey TOIDS: converting from strings to integers Sylvester Sneekly -- cheers for that. I am aware that removing the string would require us to take a few extra steps pre-processing any updates, etc. We won't be mixing data with different provenance in this project (I think!), so less need for it, although adding a provenance column would be useful. |
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Jan 22 |
accepted | Ordnance Survey TOIDS: converting from strings to integers |
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Jan 22 |
asked | Ordnance Survey TOIDS: converting from strings to integers |
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Dec 7 |
answered | Why does this simple Python OGR code create an empty polygon? |
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Nov 15 |
comment |
adding multiple points to a linestring in PostGIS Just confirming that it was unconnected a_lines causing the problem. When I extended them by a short distance (so they visibly crossed the r_lines) and then re-ran the process, the network came up as fully segmentized. |
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Nov 15 |
awarded | Scholar |
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Nov 15 |
awarded | Supporter |
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Nov 15 |
comment |
adding multiple points to a linestring in PostGIS Thank you -- that appears to work for the most part. There are a few places where an r_line segment hasn't been broken by an a_line node, but I suspect the a_lines may not actually intersect at those points. |
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Nov 15 |
accepted | adding multiple points to a linestring in PostGIS |
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Nov 15 |
awarded | Student |
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Nov 15 |
asked | adding multiple points to a linestring in PostGIS |
