#POSTGIS IRC Log - 2008-06-24

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07:13:24 lbracher: hi there! I have a LINESTRING with n points. how can I get the sub-LINESTRING between points i and j ( inclusive ), such that 1 < i < j < n?
08:58:46 CIA-6: robe * r2810 /trunk/doc/postgis.xml: Definitions for st_convexhull and st_shift_longitude
09:14:21 CIA-6: robe * r2811 /trunk/doc/postgis.xml: Fix mismatched para in intersection documentation and remove dangling command tag in Reporting Documentation Issues section.
09:15:39 jcs_: when following the install instructions, i get the following error when running psql -f lwpostgis.sql: psql:lwpostgis.sql:53: ERROR: permission denied for language c
09:19:13 jcs_: the README.postgis mentions an 'install-all-headers' Makefile rule, but it doesn't seem to be present in postgresql 8.3.3
09:41:15 jcs: nm on the lwpostgis.sql error, wasn't running it as user postgres
15:43:54 mumrah: Is it possible to write a shp file to the stdout from within postgres?
15:51:16 hobu: no. A shapefile is actually three files
15:51:22 hobu: ( sometimes more )
15:53:04 mumrah: alright, how about this then
15:53:28 mumrah: is there an effective way for me to serve shp files from MS Access with PostgreSQL/PostGIS as a backend
15:54:00 mumrah: or better yet, is there ESRI software that connects to PostgreSQL/PostGIS ( like qgis )
16:15:45 mleslie: I'm not aware of any means of directly connecting ESRI desktop stuff to PostGIS, though ArcSDE may support PostGIS in the future.
16:15:45 mleslie: There are fancy ways of doing it, such as connecting UMN MapServer to PostGIS and using IMSEmu to provide an ArcIMS interface to the MapServer.
16:16:24 mleslie: You're better off dumping/reloading shapefiles in most circumstances.
16:19:25 mleslie: Hmm. GeoServer supports serving zipped shapefiles.
16:20:01 mleslie: I don't expect ESRI software would be able to request/consume it though.
16:42:39 bitnerd: ziggis connects straight from arcgis to postgis
16:43:13 bitnerd: so does the esri data interoperability extension ( made by safe )
19:15:35 Seanasy: I have applied a negative buffer to some data and stored in a new table. Some of the features are empty and selecting astext( geometry ) returns "POLYGON( EMPTY )". However selecting ST_IsEmpty( geometry ) returns false. Are there any known reasons why this might happen?
21:11:15 lbracher: hi there! which function I could use to transform utm coordinates into latitude/longitude coordinates?
21:12:07 mleslie: ST_Transform
21:12:43 lbracher: mleslie: and what exactly is the second parameter in this function?
21:13:01 mleslie: The spatial reference system to transform the geometry into.
21:13:35 mleslie: For lat/long, WGS84 is 4326 I believe.
21:17:33 lbracher: mleslie: I´m a little bit confused in this part... the only thing I know is the datum I´m using is called here in Brasil as "Chua MG"
21:17:53 lbracher: and it replaced old one, called "Corrego Alegre"
21:18:25 lbracher: I found a description of a datum here in spatial_ref_sys, but its date is 1924...
21:18:32 lbracher: its a strange date...
21:18:41 lbracher: ops, sorry
21:18:48 lbracher: spheroid international 1924
21:19:08 lbracher: i think it was built over wgs84
21:21:00 lbracher: so, i´ll google here for it.
21:21:03 lbracher: : )
21:22:09 mleslie: There seems to be a coordinate system named Chua in PostGIS. EPSG:4224. That sound right?
21:41:54 lbracher: yes, but the info about the ellipsoid is strange... because we use GRS-67 with this datum...
21:42:22 lbracher: I really dont know, i need to make a little bit more research...
21:43:51 lbracher: mleslie: i´ll make a call to a friend tomorrow to get the right data...
21:43:55 lbracher: thanks! : )
21:44:00 mleslie: No problem.
21:44:03 lbracher: : )
21:45:39 springmeyer: lbracher: post what you learn to www.spatialreference.org !