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Feb 8 |
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Why is not ST_GeomFromEWKB() working? Thank you for your help, it still does not really work though. What I am trying to do is get the distance from a given point to the nearest boundary. This point will always fall within a polygon - that is why I include st_boundary. |
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Feb 7 |
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layer to KML conversion I had some trouble converting to KML using arcmap. I found QGIS "save as KML" option to be quite handy! |
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Dec 11 |
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What is the maximum Theoretical accuracy of GPS? I use Arcmap to set my fixed test positions and then measure the distance from the GPS positions. The results that I stated above are average and rounded accuracy values for European countries (mostly UK, Spain and Germany ) |
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Sep 17 |
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Why does ST_Transform fail? My postgis_full_version() - POSTGIS="1.4.0" GEOS="3.2.2-CAPI-1.6.2" PROJ="Rel. 4.8.0 |
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Sep 17 |
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Why does ST_Transform fail? Hi, I started testing in the UK but now it has gone global so I am trying to come around this problem. |
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Sep 17 |
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Why does ST_Transform fail? Hi, I tried it today and it worked, then I tried it again and it did not by throwing an error like this, ERROR: AddToPROJ4SRSCache: couldn't parse proj4 string: '+proj=utm +zone=47 +ellps=WGS84 +datum=WGS84 +units=m +no_defs ': latitude or longitude exceeded limits |
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Sep 14 |
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Why does ST_Transform fail? i just copied it from postgresql log file in which E indicates a string if I am not mistaken.. |
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Sep 14 |
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Why does ST_Transform fail? hi, i tried the 32647 and it still throws the same error. Thanks for your help though! |
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Sep 3 |
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How do I use st_dwithin with meters? Thank you for your answer. I used the functions above and they indeed return meters but i can only use them to calculate a distance between two latlong geometries and I need to use it to calculate distance from polygon edges. I thought of a solution with the above info, I could use st_closestPoint() to my polygon and then st_distance_sphere() which will do the trick. Problem is I am using postgis 1.4 and st_closestPoint() is unavailable. Also, I would like to use minimum code because ST_WDistance() will return a simple true/false whilst the other alternatives need more coding. |
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Mar 2 |
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postgis minimum distance among many points I found my answer here, stackoverflow.com/questions/2098186/… Thanks! |
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Mar 2 |
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postgis minimum distance among many points Yes, I am trying to get the geometry which has the minimum distance from the given point. In the provided link, it is requesting a less than or more than using a default value. which works fine in the WHERE section. |
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Feb 6 |
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Vertex point is returning None alright, ST_AsEWKT() did the job. Thanks for helping me out on the ST_Dump etc. |
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Feb 6 |
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Vertex point is returning None I am trying ST_AsText(ST_Dump(%s)) but it returns an ERROR: function st_astext(geometry_dump) does not exist on character 8 |
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Feb 6 |
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Vertex point is returning None Cool, do you know if there is a way to get the WKT of the ST_dump? I can only get the binary format..I read the doc but I do not understand how it gets the ST_AsText().. Thanks! |
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Feb 2 |
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Passing parameters to PostGIS SQL queries in Python: weird behaviour Yeap, I have excausted coding alternatives based on this document initd.org/psycopg/docs/usage.html#query-parameters.. |
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Feb 2 |
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Passing parameters to PostGIS SQL queries in Python: weird behaviour Hi, yes I tried hard coding it and still does not work... |
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Jan 27 |
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clip linestring by length You are right, some of my lines have a double ending like a double fork and that is probably causing trouble to postgis...Anyway, thank you very much for your help! |
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Jan 27 |
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clip linestring by length Right, your suggestion works fine but it seems that postgis has problems converting some specific multilinestrings into linestrings which is necessary before calling the st_line_substring function. Is there a way to come around this postgis issue? |
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Jan 26 |
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clip linestring by length thx, i ll give it a try! |
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Jan 16 |
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line segments using points hi, i am now usign 1.5 but i will definatelly install 2.0 once it gets a bit more stable. Anyway, what I did to solve this issue was to get the npoint count and create a dictionary in my code with vertex id as key and point geom as value. I could then use postgis 1.3 functions to come around my problem. Of course when 2.0 is installed, i will be able to greatly optimise my code :) |
