Aerial images vs OSM - which is right?

eteb3 · 2018-12-01T14:58:24.000Z

Hi all

Is it possible to find out the date an aerial photo was taken?

This object (warehouse?) was added 8 years ago - but Bing and Esri both have houses in that location.

https://www.openstreetmap.org/way/87863090#map=18/52.56089/-0.25990

I could survey the object on the ground, but it’s a fair old way from me. Common sense suggests that warehouses are more likely to have been demolished for housing rather than vice versa, but I think that probably isn’t strong enough for verifiability.

What’s the best way to proceed? If I had a date for the image I could adjudicate between the conflicting evidence.

Thanks,

Edward

Hendrikklaas · 2018-12-01T16:27:31.000Z

Hi Eteb3,

The building east to your warehouse seems to be used by Bonack Ltd as office at the end of a living or residential street
The rest looks like it as been demolished. Due to a new development of houses. I could not find the project but you might.
Try for instance another editor with more choice to vary your aim or background.

nevw · 2018-12-02T00:18:55.000Z

The Bing imagery displays ‘Metadata Capture Date 6/18/2017-9/24/2017’ by right-click on the background image and ‘Show tile info’ in JOSM which I assume is the image capture/processing date and appears, in comparison to Esri and Digitalglobe, to be the most recent and displays the new houses.
Esri and Digitalglobe don’t display similar type of info, [edit see @smaprs comment below].

smaprs · 2018-12-02T09:28:44.000Z

eteb3:

Is it possible to find out the date an aerial photo was taken?..

Yes, it’s possible:
https://forum.openstreetmap.org/viewtopic.php?pid=727195#p727195

-For Bing, already said, is rigth-click;
-For Digital Globe images have to add as an additional layer “Imagery Vintage”, from the list of supported layers in “image preferences”.
https://wiki.openstreetmap.org/wiki/DigitalGlobe#Imagery_Vintage

Go to: JOSM > Imagery > Imagery preferences
and have to “activate” the imagery layers you require (adding it to your prefered layers).
Regards,

SK53 · 2018-12-02T11:52:06.000Z

A couple of other sources which can help to resolve this type of problem:

os.openstreetmap.org : tile layers for every version of OS StreetView (OSSV) Open Data maps from 2010-2016, including a diff layer. This shows the warehouses as being in existence for the whole period. Because OSSV represents snapshots at a given time it can be a useful tool to help date imagery if one suspects changes.
OSM-Nottingham: this site now allows many Open Data sources to be searched throughout the UK. A simple query for “Peterborough” in that area (http://osm-nottingham.org.uk/?z=17&lon=-0.26032&lat=52.56105&bgl=OSM,1,15&s=peterborough&st=SearchOpendataJson&uc=1) shows a number of limited companies registered at streets which aren’t on OSM: Buttermilk Drive, Mollis Close and Cumberleaf Close. Given the location of post code centroids it may be possible to assign street names from this data.
OS Open Data Local. This needs to be downloaded & inspected (eg in QGIS) but should be more uptodate than OSSV and may well show the new roads.

In other words you can safely remove the warehouses (if you are worried about others adding them back you can make them demolished:building, but I don think this is needed). You also have a better handle on imagery dates which may be useful more generally, but watch for sharp cutoffs between newer & older imagery (I think these are usually near edges of suburbs).

eteb3 · 2018-12-02T17:53:31.000Z

Thanks all for all of those.

@SK53, especially useful. Just one clarifying question:

SK53:

watch for sharp cutoffs between newer & older imagery

What are ‘sharp cutoffs’?

SK53 · 2018-12-02T22:44:24.000Z

We used to have Bing imagery in N Nottingham (Bulwell to be exact) which went from something like 2009 imagery to 2002 in the middle of a building which a) got demolished and b) replaced on more or less same ground plan. It was hellishly confusing working out what the actual situation on the ground was, until we realised there was such a big difference in dates. Of course in many places such changes are obvious, but it’s as well to be on guard against them.

eteb3 · 2018-12-03T20:55:17.000Z

Lol - I see! Thanks!!