UKH

Does anyone know where I can source aerial photos with OS grid lines superimposed, and (crucially) to scale - i.e. I want a photo at 1:10,000 scale? Plenty of websites offering photos, a few offering highly technical digital mapping type stuff I can't understand...suggestions appreciated!

Could you get OS mapping on bing maps, screenshot it, then switch to satellite view and overlay in photoshop. 

Erm, possibly, but one issue would be getting the scale correct...I'd rather have a professionally printed map sheet sized photo

I think you are looking for someone with Autocad Civils 3D or perhaps some other civil engineering software package. I’m pretty sure they can bring in aerial photography to OS grid.

Fatmap will superimpose gridlines (of varying sizes depending on zoom level) over satellite imaging - but they don't align with OS grid lines. They are to scale though...

Some of that 'technical stuff' might be to do with projection transformation. If you want a true OS grid you will need to have the image transformed to the OSGB36 projection. Most of the free online mapping is to a different projection (WGS84 or something similar for web use). That's why when you view OS maps on Bing, for instance, the grid lines are 'on the wonk'; not perfectly horizontal & vertical.

OS Maps app is, unsurprisingly, projected to OSGB36. So that would work. Scaling to fit when printed could be done in a graphics tool, or even in the print dialogue of Acrobat; I often print A3 maps to PDF, and know the scaling tweak required to get my printer to print correctly to scale.

Few printers print true to scale, across the entire page, so x and y scaling is often required, and, even then, cannot prevent some scale distortion across the page. Then there is front/back side registration & rotation...

Thanks, which is exactly why I am looking for someone to whom I can say "give me an aerial photo 30cm wide centred in grid reference x,y at 1:10,000 scale with OS gridlines overlaid" !

try. aqua4 in the hope valley.

Is this any good? https://mappingsupport.com/p2/gissurfer.php  Does UTM grid.

There are options on this that might help, I haven't had a proper play though and definitely doesn't do 1:10,000 scale maps.

https://wtp2.appspot.com/wheresthepath.htm

Not sure if this link will work correctly but on the National Library of Scotland's website, you can select an over- and under-lay map, and use a slider in the bottom left corner to adjust the transparency of the upper one to reveal the lower:

https://maps.nls.uk/geo/explore/#zoom=16.2&lat=50.52745&lon=-2.4371...

Oh, I really like that...

Fascinating to see how little has changed on Portland (your example location). Apart from the naval bits...

The National Library of Scotland have a "side-by-side" map viewer as well as the overlay Fraser links.  I prefer side-by-side.

https://maps.nls.uk/geo/explore/side-by-side/#zoom=13.6&lat=54.36748&am...

(Select LiDAR DTM 50cm-1m on the right side for incredible elevation maps showing lots of features)

Thanks, yes I had found that but I need a hard copy at 1:10,000 scale...to explain further I have a geological map on tracing paper which I am trying to compare to ground features from the air, so need to be able to overlay it (i) at correct scale and (ii) with gridlines to align

Gotcha. How big an area is it you need? If it's not too huge, I could try and get the required area to scale using a combination of the scale bar on the map and the grid lines. With a bit of layer work in Photoshop, it shouldn't be too tricky. 

Edit: it would also depend on how accurate you'd need it to be!

If you have access to a GIS package like ARCGIS then you can setup a project in OSGB, import an OS basemap, import and georeference your aerial photo. In excel create a text file with 4 columns for the start easting, start northing, end easting, end northing. Set the grid line interval to your choice. Repeat for the other direction. Import these two file as data and then use the points to seismic line feature to generate your grid.

then you can import your geological map geo reference it ( with a bit of stretch and squeeze if needed) and then superimpose over the aerial photo.

perhaps a bit more complicated than earlier suggestions but you do have all your maps together correctly referenced and overlain. You can also add more images

I thought of suggesting the same but thought it might be a little complicated for someone with no experience of GIS. And QGIS is free - see https://www.qgis.org/en/site/

I might be able to help. I have professional mapping software (ArcGIS) for part of my work and while my normal use is very different, I have done something similar for a friend to support a land-use application.

The posts from captain paranoia and apache capture the technical side well, and anyone's day is improved by Fraser's suggestion of a visit to the National Library of Scotland's website.

For a home-grown solution using a tracing-paper overlay, you might manage with 4 control points rather than a full grid. Effectively the corners of a rectangle bounding the area of interest - placed as marks on the satellite image at known OS coordinates to line up with your overlay.

As noted by captain paranoia, websites like GoogleMaps use the WGS84 projection so an OS grid would look skewed when placed on top (the amount of skew depending on the location). So you'd want to get your satellite image from a source that uses the OS grid projection (OSGB36) - like the NLS.

As long as your satellite image and tracing paper have the same OS grid projection - 4 control points are enough to successfully overlay the two. As others have noted there are issues with printers relative x/y scaling (which might vary across the page but let's hope you're not after high accuracy).

Depending on how big your tracing paper is, how good a printer you have access to, and your accuracy needs, this might be a rewarding approach and entirely in the spirit of what you're looking to do.

A more professional approach would be to take an reasoanably accurate scan of your tracing paper and use it to create a layer that then gets 'georeferenced' in GIS software (basically attaches a spatial reference to the image). That then allows you to do stuff like the nice NLS interface.

Very happy to help if you want to email me - either with steps towards the home-grown option or a more computer-based approach.

Thanks Grigor (and Fraser)...that's really generous and in the true spirit of UKC. I'll keep plugging away at trying to find a commercial provider not least as (to pick up one question) it does need to be as accurate as possible, as the area concerned is quite complex geologically and even at 1:10,000 1mm out is 10m on the ground! The size of the map (to answer another question) is c.60cm x 60cm, so my bog standard A4 laserjet isn't going to cut it

Is there gold in tham thar hills?! 😁

Good luck.

I've just looked at his profile: "mostly retired..." and a picture of him by the sea. Clearly a pirate with one last treasure map!

Nic - the offer stands, feel free to reach out if you struggle to find an option commercially.

My general thought is that you may have more success finding someone to scan your tracing-paper map and 'georeference' it - giving you a high resolution digital image with a spatial reference attached. Though perhaps I'm just accustomed to working in the computer realm and am struggling to imagine a printed satellite image being that easy to work with alongside a transparency. 

A well georeferenced scan is arguably a more flexible product to purchase than a printed sheet. Again I guess it depends on outlook and what you'll enjoy working with. I note that the NLS mapping tool includes the option to add your own layers (including a georeferenced scan, "I assume"). You'd want to confirm that the NLS satellite imagery had the required clarity/resolution in the area of interest (it can vary quite a bit).

Happy treasure hunting!

Well if I find any gold I promise to split it 3 ways...but just to let you down gently actually it's my old undergraduate geological mapping area which is principally dolerite and a sequence of siltstones and tuff! *Not* gold-bearing as far as I know.

Amongst other things I wanted to see how good I was at locating by compass resectioning (this being long before the days of GPS!). Also there's a lot of stuff which is far more visible from the air (but traceable on the ground if you know what you're looking for) which I also want to look at in retrospect.