jncc / web-mapper-core

Common web-mapper components for the JNCC websites

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MPA mapper polygon load issue

HelenwoodsJNCC opened this issue · comments

We are having a bit of an issue with some of the MPA polygons, whereby they only partially displaying when zooming in close, specifically those with complex inshore boundaries, e.g. Strangford Lough SAC. @JamesPe any ideas why this is? Thinking it might be something that could be solved by caching the layer potentially?

image

Hmm - are they all polygons - or are some lines etc ? I assume they are all one layer in geoserver?
Is it a timeout issue - that geoserver is failing to keep up?
@HelenwoodsJNCC can you send me a permalink highlighting the issue ?
Also just possible its a network connectivity issue at your end - but again if I could see that would help identify

@JamesPe they are all polygons and in a single layer on Geoserver.

Here is an example:
https://mapper.mpa.jncc.gov.uk/?zoom=10&center=-5.544,54.430&layerIds=43&baseLayerId=1&activeFilters=

I can get the same effect here directly in geoserver- https://staging.ows.emodnet-seabedhabitats.eu/mpa_mapper/wms?service=WMS&version=1.1.0&request=GetMap&layers=mpa_mapper:sac_mc_full&styles=&bbox=-2155423.5,6417485.5,374296.3125,8592683.0&width=768&height=660&srs=EPSG:3857&format=application/openlayers

Zooming in at steps and at one zoom level strangford disappears.
I can only imagine its a bad polygon at a certain zoom level

@HelenwoodsJNCC been messing with your caching settings for that layer.
Changing the metatiling settings for the cache has improved (but not removed) the issue.
I'm pretty sure that this means its probably a n issue with a multipart polygon / index - i.e. the polygon isn't showing on the tile because geoserver/postgre doesn't believe the polygon exist on that tile.

I don't have access to your postgre db fro MPA mapper - so not much more I can do at that - but hopefully tahts pointed you in the right direction

@JamesPe thanks, will do some investigating in the db.

@JamesPe Turns out the data had been imported with a simple polygon geometry type rather than multipart polygon geometry type. I have fixed this for the SAC layer and it seems to work ok now.