[GRASS-user] The upper limit for displaying large vector layers

[Markus Neteler]

hi Peter,

On Wed, Dec 10, 2008 at 9:09 AM,  <peter.loewe at gmx.de> wrote:
> Hi,
> the current GRASS versions share a constraint regarding the maximum
> size of _displayable_ vector layers.
> This affects both traditional GRASS monitors and map displays.

[which GRASS version, which OS?]

> While GRASS is capable to ingest and process rather large vector data sets,
> these can _not_ be properly be displayed when their size exceeds a certain
> threshold [which needs to be further pinpointed].

What does really happen? Crash? Slow? Missing vectors?
If crash (maybe the best case), please run it in gdb/ddd and
create a backtrace (see GRASS Debuging in the Wiki). Then
we could try to find the bottleneck (maybe integer overflow).

> The effect can be experienced when using the GADM dataset. It is provided here:
> http://biogeo.berkeley.edu/gadm/data/gadm_v0dot9_shp.zip
>
> The shape file holds about 600+Mb of areas (global administration boundaries).

You can import it successfully with v.in.ogr?

If successful, could you make the GRASS *location* available?
Would save us time to avoid the (lengthy?) v.in.ogr step.

> While _working_ with the data poses no problem (just as expected),
> attempts to display (d.vect... ) it in GRASS have failed so far.

In which sense?

> It is interesting that visualizing data of this size freezes GRASS and QGIS,
> yet is no problem for Java-based applications like uDig once the heapsize is cranked up.

Sure because uDig is non-topological. That's way easier to handle.

Please send a precise description of the problem.

Markus