While importing a polygon file grass7.5svn balked:
"23125 areas represent multiple (overlapping) features, because polygons
overlap in input layer(s). Such areas are linked to more than 1 row in
attribute table. The number of features for those areas is stored as
category in layer 2
"If overlapping is not desired, the input data can be cleaned by snapping
vertices to each other.
"Estimated range of snapping threshold: [1e-09, 1]"
Please suggest snap parameter(s) to be applied with v.clean and when to
stop cleaning.
Rich
On Mon, Jun 25, 2018 at 8:26 PM, Rich Shepard <rshepard@appl-ecosys.com> wrote:
While importing a polygon file grass7.5svn balked:
"23125 areas represent multiple (overlapping) features, because polygons
overlap in input layer(s). Such areas are linked to more than 1 row in
attribute table. The number of features for those areas is stored as
category in layer 2
"If overlapping is not desired, the input data can be cleaned by snapping
vertices to each other.
“Estimated range of snapping threshold: [1e-09, 1]”
Please suggest snap parameter(s) to be applied with v.clean and when to
stop cleaning.
The above suggested range for a snapping threshold applies to v.in.ogr. Is there something unclear about the above suggestion?
When to stop cleaning depends on the data: do you want to get rid off all overlaps? In this case you could also remove small areas with v.clean tool=rmarea. The threshold depends on the input data. There is no universally good threshold.
Markus M
Rich
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On Thu, 28 Jun 2018, Markus Metz wrote:
The above suggested range for a snapping threshold applies to v.in.ogr. Is
there something unclear about the above suggestion?
Markus,
I assumed this.
When to stop cleaning depends on the data: do you want to get rid off all
overlaps? In this case you could also remove small areas with v.clean
tool=rmarea. The threshold depends on the input data. There is no
universally good threshold.
Okay. That's good to know.
Best regards,
Rich