14,677 reputation
13368
bio website sites.google.com/site/mwtoews
location Wellington, New Zealand
age 34
visits member for 3 years, 8 months
seen 2 hours ago

I'm a hydrogeologist. An expert of many random things.


10h
comment How to store lat/long in PostGIS database?
That chart is misleading. There is only S = south and N = north. China is in the North.
10h
comment How to store lat/long in PostGIS database?
Since Beijing is in the Northern hemisphere, you want zone 50N, or EPSG:32650, although 50S will sort-of work.
11h
comment How to store lat/long in PostGIS database?
You need to transform to a different SRID. You didn't transform anything since 4326=4326.
12h
comment How to store lat/long in PostGIS database?
If you transform your coordinates into easting and northing, it would also make sense to also convert elevation into metres, so that functions like ST_3DLength work. However, it doesn't influence projection issues on a flat map.
22h
comment Gdal/QGIS resampling asc file
Be sure to use -r average, otherwise the downsampling will pick the middle pixel and ignore the other 8.
1d
answered Removing small polygons gaps in a Shapely polygon
1d
comment How to store lat/long in PostGIS database?
Looks like there is some bias, but I'm not convinced it is a projection issue since some parts match up. Also, I'm no expert with how smartphones obtain their position, but check out this thread.
1d
answered How to change the SRID of exisisting data in PostGIS?
1d
comment How to store lat/long in PostGIS database?
Yes, WGS84 is SRID=4326. Location estimates from smartphones are not great, so it is expected that your lines would look like zig-zags jittered around the expected locations.
1d
answered How to store lat/long in PostGIS database?
1d
answered Subsetting a x,y,z into a text file from a large xyz text file
1d
comment Subsetting a x,y,z into a text file from a large xyz text file
update your question to show the command you tried and errors (except for the usage info)
1d
revised Subsetting a x,y,z into a text file from a large xyz text file
specify output format
2d
comment Invalid join selectivity error in postgis 2.1.3
Yeah #2543 should be fixed. This is probably beyond a simple question. Ask on a PostGIS mail list, providing more details than you have here, such as the exact error message, PostGIS version, etc.
2d
comment Geocode as soon as PostGIS table is updated
There are dozens of other languages (e.g. PL/Perl) but are less used and supported. I would use PL/Python because it works, if used correctly.
2d
answered Geocode as soon as PostGIS table is updated
Oct
26
comment gdalnumeric in python virtualenv
The description at PyPi that you linked to says it is deprecated, and the source shows that change was in 2007. You should use osgeo.gdal_array instead.
Oct
24
comment Subsetting a x,y,z into a text file from a large xyz text file
It is installed with GDAL, often packaged as gdal-bin. For Windows, install with OSGeo4W.
Oct
24
comment gdalnumeric in python virtualenv
As a side note, gdalnumeric was deprecated 7 years ago (in 2007).
Oct
23
comment Are any fictional worlds available in some GIS format?
My favourite fictional maps are of the Koana Islands, but I'm not sure where to obtain the base data for it.