Comments (12)
oh also - I'm reopening this issue.. best
was a good enough hack when we really only had Bing, Mapbox, and whatever local imagery to choose from. We have so many more imagery to trace from now that we need something a bit more nuanced (this is a great problem to have!)
from editor-layer-index.
For this project a useful quality metric in addition to the capture date would be ground resolution. This of course only can be specified for homogeneous image sources. But together with the date it would allow applications to perform a better assessment of the image sources. If for example a source like Bing reaches the limit as you zoom in or has an extremely old date specified in the tile metadata (like the standard 1/1/1999-12/31/2003 for the Geocover basemap) the application could look into the available other sources and suggest to the user to use whatever promises a better quality at the current location.
from editor-layer-index.
To be honest, I'd prefer to just build an entirely new thing that can keep track of - for a given quadkey which imagery is best, along with whatever adjustments need to be made (offsets, brighness/sharpness, etc).
@Zverik's imagery offset database is pretty good, but I'd like to take it a step further!
from editor-layer-index.
@imagico that would not address the issue that quality can vary drastically in the same imagery source even with the same nominal resolution (naturally we don't even record that currently) and in the end quality in this case is only meaningful as a relative measure (not to mention all the issues with zoom levels and so on) and that is why I would prefer a solution as I outline here #112 (comment)
from editor-layer-index.
We have an indication of approximate resolution with maxzoom for TMS sources. It's only approximate, but imagery resolution differences are frequently several powers of 2.
from editor-layer-index.
Due to the variable scale of the Mercator projection the maximum zoom level does not say much about the resolution. In the osmim the maximum zoom currently varies between 10 and 14 for example despite all images currently offering either 10m or 15m ground resolution.
from editor-layer-index.
Due to the variable scale of the Mercator projection the maximum zoom level does not say much about the resolution. In the osmim the maximum zoom currently varies between 10 and 14 for example despite all images currently offering either 10m or 15m ground resolution.
For imagery over a reasonably small area, like most, the variable scale doesn't matter as it impacts all imagery the same. A bigger current issue is probably the high number of sources with 22 as a max zoom (~2-3cm where it is) but the imagery is 20-50cm
from editor-layer-index.
from: #164 (comment)
Our hope for this best flag is that local contributors can use it to mark imagery that they know to be better than Bing/Mapbox. For example, "Kanton Zürich 2015 10cm" is marked "best" because people from Switzerland say so, not because of the imagery's age and resolution. Tomorrow Bing may update their imagery and then "Kanton Zürich 2015 10cm" will no longer be the best source there, and ideally somebody from the Swiss community will notice this and open an issue to remove the flag.
Closing this issue for now.. Consider "best" as meaning "better than Bing according to local mappers".
from editor-layer-index.
Another "solution" might be to turn around the whole "best" concept:
Remove the best attribute from all imagery entries. Create new separate area polygons and assign one layer as best to this area (by the id of the layer). These areas can be a whole country or a smaller part or whatever.
However this doesn't solve all problems and creates new ones:
- "best" can still mean different things (date, clouds, resolution, orthorectification,...)
- the new polygons must not overlap. So a common database for all these polygons would be required. Something like the osm database just for these polygons.
Not sure if it is worth the effort. It all sounds a bit complex too.
from editor-layer-index.
What about having a bestoverride geojson featurecollection that has polygons where the best background is their bestmapid attribute? Or do we want something more objective than "best"?
from editor-layer-index.
There was also :
Best-best image for region? #390
from editor-layer-index.
I must also question the utility of a simple "best" attribute. This merely splits available imagery sources into "first class" and "second class", without quantitative meaning. This is especially noticeable near borders, where (1) the neighboring classifications spill over and (2) the neighbors show your area as blank.
I think the situation needs objective attributes quantifying the image data. The common points of contention (in the "best" debate) are vintage, resolution, and coverage.
- Vintage: some sources have it, some don't. The date ranges vary too, some stating a single month, some spanning a year or more. This should ideally be attributed to each tile, but if a polygon for the imagery source exists, then for that polygon.
- Resolution: hopefully a decent measure of actual optical resolution (what you can see), regardless of digital resolution (the pixels). If I lay a checkerboard pattern of black and white tiles on the ground, the tiles being 0.1 m along each edge, and the pattern is blurry or hard to make out (3 dB cutoff or whatever), then that should not be called "0.1 m resolution".
- Coverage: plenty of locally high resolution imagery sources have associated polygons. If any attribute (resolution, vintage) differs noticeably in this polygon, then why not split the polygon into several?
For many sources, those are hard to get authoritative values for. I think it's reasonable to guess date ranges and resolution from imagery, and to draw polygons by what the source actually shows right now.
With such attributes, users could choose their own ranking of available sources. Do I want the most recent images, regardless of resolution? Do I want the best resolution, even if it's older? Do I want some mixed weighting? Who else can tell but I?
from editor-layer-index.
Related Issues (20)
- King County, WA (Seattle, US) Orthoimagery 2019, 2021 HOT 2
- Add Ljubljana high-res orthophotos HOT 2
- rizwan HOT 2
- France previous IGN Ortho HR are not loading
- TIGERweb
- Change of URL for "IndianaMap Orthoimagery - Latest Available"
- WMS dataset layers of City of Tampere
- Reinstate NRW_Ortho as best for NRW HOT 10
- icon for "LINZ-NZ-Bay-of-Plenty-2014" layer is broken HOT 3
- in some areas vector map, not aerial, is default HOT 4
- NRW vDOP is blank while listed as best imagery for at least some areas HOT 11
- Mecklenburg County NC Imagery Not Working
- Update OS OpenMap Local (Great Britain)
- Request: Multiple custom layers HOT 3
- Default imagery doesn't load in JOSM HOT 9
- au/act urls will need to be updated due to server shutdown 31 May 2024. HOT 2
- South Central Ontario Orthoimagery (2018)
- Imagery layers not working
- Fairfax County Orthoimagery is broken
- City of Bern (CH) WMS out of service HOT 1
Recommend Projects
-
React
A declarative, efficient, and flexible JavaScript library for building user interfaces.
-
Vue.js
🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
-
Typescript
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
-
TensorFlow
An Open Source Machine Learning Framework for Everyone
-
Django
The Web framework for perfectionists with deadlines.
-
Laravel
A PHP framework for web artisans
-
D3
Bring data to life with SVG, Canvas and HTML. 📊📈🎉
-
Recommend Topics
-
javascript
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
-
web
Some thing interesting about web. New door for the world.
-
server
A server is a program made to process requests and deliver data to clients.
-
Machine learning
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
-
Visualization
Some thing interesting about visualization, use data art
-
Game
Some thing interesting about game, make everyone happy.
Recommend Org
-
Facebook
We are working to build community through open source technology. NB: members must have two-factor auth.
-
Microsoft
Open source projects and samples from Microsoft.
-
Google
Google ❤️ Open Source for everyone.
-
Alibaba
Alibaba Open Source for everyone
-
D3
Data-Driven Documents codes.
-
Tencent
China tencent open source team.
from editor-layer-index.