Creating map layer at 10 fig grid reference

[DrGwenH]

I'm working on orchid records with a nature reserve with the raw data in a cvs file with each row being a single record and a 10fig grid reference. I've managed to crate some very useful maps showing the records as points & on a 10m atlas squares styled to show difference abundance levels. What would also be useful is a way to create a 1m atlas squares which would effectively combine all the data points which have the same 10-fig grid references and allow abundance levels to be shown in a much finer scale. Is it possible to get this added as an option? (I realise it's only applicable to within site projects like mine) Or is there another way to do this? Quite a few of our spreadsheets from survey work end up with several records at the same grid reference, I could manipulate the data in excel to combine rows but if there's an easy way to do it in QGIS that would be great. Thanks! (Sorry if this isn't the best platform to raise this - I was directed here by the chap running our training course!)

[burkmarr]

Hi - thanks for your question. It's fine to put questions like that here so that other people can potentially read and learn from them tool.

As you've found, there's no 1m aggregation options - I'm not sure why I left that out and I will add it for the next release. In the meantime, you could try this workflow.

1. Map your records using the 'records as grid squares' option.
2. Use the 'delete duplicate geometries' tool from processing toolbox to create new temporary layer with a single square at each 10 fig GR.
3. Use the 'join attributes by location (summary)' tool to create a new layer based on the temp layer you just created that counts all the squares from the original layer that are 'contained' within the square from the temp layer. When running this tool, you will need to select an attribute from the original layer and specify that it is to be 'counted'. Alternatively, if you have an abundance attribute in your original layer, you can chose to 'sum' those values.

That will all give you a new layer with a single geometry for each unique square and an attribute which counts (or sums an attribute value) all those squares from the original layer at each square position. Hope that's a useful workaround for now.

[DrGwenH]

Thank Rich, that work around sounds like it’ll give exactly what I was interested in.

Cheers!

Gwen

From: Rich Burkmar [mailto:notifications@github.com] Sent: 22 November 2018 06:54 To: burkmarr/QGIS-Biological-Recording-Tools QGIS-Biological-Recording-Tools@noreply.github.com Cc: Gwen Hitchcock Gwen.Hitchcock@wildlifebcn.org; Author author@noreply.github.com Subject: Re: [burkmarr/QGIS-Biological-Recording-Tools] Creating map layer at 10 fig grid reference (#24)

Hi - thanks for your question. It's fine to put questions like that here so that other people can potentially read and learn from them tool.

As you've found, there's no 1m aggregation options - I'm not sure why I left that out and I will add it for the next release. In the meantime, you could try this workflow.

1. Map your records using the 'records as grid squares' option.
2. Use the 'delete duplicate geometries' tool from processing toolbox to create new temporary layer with a single square at each 10 fig GR.
3. Use the 'join attributes by location (summary)' tool to create a new layer based on the temp layer you just created that counts all the squares from the original layer that are 'contained' within the square from the temp layer. When running this tool, you will need to select an attribute from the original layer and specify that it is to be 'counted'. Alternatively, if you have an abundance attribute in your original layer, you can chose to 'sum' those values.

That will all give you a new layer with a single geometry for each unique square and an attribute which counts (or sums an attribute value) all those squares from the original layer at each square position. Hope that's a useful workaround for now.

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHubhttps://github.com/burkmarr/QGIS-Biological-Recording-Tools/issues/24#issuecomment-440930712, or mute the threadhttps://github.com/notifications/unsubscribe-auth/ArHQ3DSCiY5-IMXPDyAresYDQp31cGWrks5uxkoEgaJpZM4YrboF.

Dr Gwen Hitchcock Monitoring & Research Officer Direct line: 07872 418281

The Wildlife Trust for Bedfordshire, Cambridgeshire & Northamptonshire Unit 2 St Johns Barn Griffin Farm Conger Lane, Toddington, Bedfordshire, LU5 6BT Office: 01525 874317

We work to make our three counties a place where nature can flourish and enrich the lives of the people who live here. With your help we care for local wildlife and more than 100 nature reserves. Volunteering your time or donating money to us will directly benefit local wildlife.

Tweet: @wildlifebcn Like: /wildlifebcn Visit: www.wildlifebcn.org

Registered Office: The Manor House, Broad Street, Great Cambourne, CB23 6DH. Registered in England 2534145. Registered charity No. 1000412

This email is strictly confidential. It may be read, copied and used only by the intended recipient. Please contact the sender immediately if you have received this email in error. You can change how you hear from us at any time by updating your preferences at www.wildlifebcn.org/yourdetails or by contacting us. We process personal data in accordance with our privacy notice which can be found at www.wildlifebcn.org/privacy.

[burkmarr]

Add 1 metre aggregation option

[burkmarr]

Already actioned.