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As part of a planning application I have to provide an existing building ground floor level relative to local levels/ local benchmark level. I can't locate any benchmarks near the property. Does anybody have any idea as to how I go about doing this? The property in question is in Scotland, if this makes any difference.
Any help appreciated.
Is this any help?
https://www.ordnancesurvey.co.uk/benchmarks/
It's so long since I've done any surveying I can't even renember how we found out where benchmarks were.
Probably done with GPS now. Perhaps the local authority in question could help with local benchmarks. Like Rob it's so many years since I did any surveying or setting out, I've no idea how we used to locate them.
Apart from the OS 190 fundamental bench marks, it is now all done with dGPS. Either you are ‘stuck’ with some of the 1950-1980s unmaintained network that Rob listed, or could you use a spot height from a map (for example there are known heights on the road networks). Any idea as too what vertical resolution you need it? I could look on the academic mapping data we have if you get stuck.
Seems an odd request if not part of a professional survey where they should have dGPS kit.
If you're into playing with IT, have a look at the Scottish Remote Sensing Portal and see if there is Lidar data for the area; it's all public domain now, but you'll need a GIS application (such as QGIS) to read it. Not sure about Scotland but in England you can get Lidar data that gives ground level to 25cm.
Are the not usually on prominent buildings , town house, toll booth , library and bridges etc os maps ?
Are the not usually on prominent buildings , town house, toll booth , library and bridges etc os maps ?
That what the OS list Rob linked too gives the locations and elevations of. They haven’t been resurveyed for typically 20+ years but I’m imagining a bit of land level change doesn’t matter in this context. That’s why they are no longer listed on OS maps.
Get your nearest spot height from your local OS map and use a dumpy level to transfer height difference to your ground floor. Give them this level to three decimal places; job done. I doubt they will ever check the accuracy. It should be good enough for planning and gives a tick in the box for the planners.
Thanks.
Excuse my ignorance but am I correct in thinking I have to pay for access to an OS map, or is there a free online service anywhere?
I did try with the benchmark list but can't find my co-ordinates anywhere!
3.17 For the purposes of Classes 1A to 3E of the General Permitted Development Order, the height of the development is measured from the lowest part of the surface of the ground adjacent to the building or structure.
3.18 In all other instances the height of the building or structure is calculated from the highest part of the surface of the ground immediately adjacent to the building or structure.
3.19 The ground is the natural ground and would not include any addition laid on top of the natural ground.
Andy,
If you use grid reference finder you will get your coordinates.
If you PM me your address i can check if we gave threshold levels in your area.