Post

2 followers Follow
1
Avatar

Issues with flood data WFS bounding box

Hello, 

We used the previous version of the WFS to access various flood data, but we're having difficulty with the new services

We use FME to fetch the data. We need to constrain our request to avoid a gateway timeout error and we've have had success getting some features through by using a max features parameter, but not using a bounding box which is the preferred method. We've had two different responses, one saying the bounding box is not recognised when using the URL generated by FME, and a second showing the bounding box coordinates as 0 when modifying it slightly.  

It definitely seems to be the bounding box which is the issue so any suggestions on this appreciated. 

Katie Morgan //

Official comment

Avatar

Hi Katie,

Apologies you are having difficulty using this data, we are currently investigating the issue.

This is a high priority and will aim to get it fixed ASAP. 

Many thanks

Ella Fotheringham 

Environment Agency

Ella Fotheringham //
Comment actions Permalink

Please sign in to leave a comment.

8 comments

0
Avatar

Hi Katie,

Apologies you are having trouble with this dataset.  Please see the guidance below from our technical team.

The WFS construct was invalid, you need to specify the coordinate system srsNAME and ensure proper TYPENAME as well as defining the BBOX with a reprojection to 27700, as the coordinates used are in British National Grid. The default OGS coordinate system is WGS84 (srsNAME=EPSG:4326). This has been amended in the URL below:

https://environment.data.gov.uk/spatialdata/historic-flood-map/wfs?SERVICE=WFS&VERSION=2.0.0&REQUEST=GetFeature&TYPENAME=Historic_Flood_Map&BBOX=444018,321614,489124,401169,EPSG:27700&srsName=EPSG:27700

I hope this helps.

Ella Fotheringham

Environment Agency 

Ella Fotheringham 0 votes //
Comment actions Permalink
1
Avatar

Thanks Ella this worked great. It's frustrating that when we try to use FME to do this (it worked previously) an invalid request is generated. 

Still having some issues with the Flood Zone 2 and 3, I suspect because the coordinate order is inverted for those datasets (as per this forum post) the bounding box we are using in the URL will not work? 

Katie

Katie Morgan 1 vote //
Comment actions Permalink
1
Avatar

As an update to my previous comment, flipping the bounding box coordinates worked fine to query the Flood Zone data - I'd forgotten that WFS 1.1.0 and 2.0.0 treats coordinates as YX rather than XY. 

I was still having a time out issue when we just used a bounding box and didn't specify a max feature, so just in case anyone else is having similar issues, the workaround I found was: generate a grid for the area I'm interested in, extract the XY max and min for each block, and feed this into the GetFeatures URL. Chopping the request up into smaller bounding box areas seemed to do the trick and can be automated reasonably quickly with FME. 

Katie Morgan 1 vote //
Comment actions Permalink
0
Avatar

Thank you Katie for this useful information. 

Ella Fotheringham

Environment Agency

Ella Fotheringham 0 votes //
Comment actions Permalink
1
Avatar

Hello again. Unfortunately still having real issues with Flood Zone 3, and only this WFS - everything else is working fine with the methods discussed previously.

I get a gateway time-out error very quickly, the only way I can get any data through even when using small search envelopes is to limit the max features per request to something very low, e.g. 10 which really isn't practical. I've tried it from within and outside my corporate network with the same results. Has anyone else had this issue?

Thanks!

Katie Morgan 1 vote //
Comment actions Permalink
1
Avatar

Hi Ella, 

Thanks - I've actually submitted a support request to the helpdesk about this, the ticket number is 268. 

Thanks. 

Katie Morgan 1 vote //
Comment actions Permalink