[GRASS-user] Estimating import time for large data file

[Helmut Kudrnovsky]

Rich Shepard wrote
> On Sun, 31 May 2020, Helmut Kudrnovsky wrote:
> 
>> it seems the projection of your data (+proj=merc) doesn't correpond to
>> the
>> Enterprise Office's projections you mentioned (+proj=lcc, +proj=lcc,
>> +proj=longlat)
> 
> Helmut,
> 
> That's true. So I created a new location for this huge shapefile. The
> issue
> has nothing to do with the projection but the time to import it. And
> Moritz
> and Markus N. both suggested using ogr2ogr with a simplify value. My
> question is how to select that value for a first try.
> 
> Thanks very much,
> 
> Rich
> _______________________________________________
> grass-user mailing list

> grass-user at .osgeo

> https://lists.osgeo.org/mailman/listinfo/grass-user

I think it is EPSG 3857.

Have you read the wiki entry (from the link I mentioned in a previous mail)?

taken from there:

"While the Web Mercator's formulas are for the spherical form of the
Mercator, geographical coordinates are required to be in the WGS 84
ellipsoidal datum. This discrepancy causes the projection to be slightly
non-conformal. General lack of understanding that the Web Mercator differs
from standard Mercator usage has caused considerable confusion and
misuse.[4]:87 For all these reasons, the United States Department of Defense
through the National Geospatial-Intelligence Agency has declared this map
projection to be unacceptable for any official use.[7]"

thus I suggest, as already before, to use another projection appropriate for
your working area. 

regarding values for ogr2ogr, maybe ask also on the GDAL mailing list .




-----
best regards
Helmut
--
Sent from: http://osgeo-org.1560.x6.nabble.com/Grass-Users-f3884509.html