Load testing new MapKnitter exporter! Help wanted!
We've just published the new MapKnitter cloud exporter for the first time, in a beta mode. We're very excited to try it out before putting some final touches on it!
The design and user interface is not complete (no worries, it'll improve!), but we'd like to ask people to try running exports on some big maps to test out the exporter on some tough maps.
Edit the map
To run the export, click Edit this Map:

Select images
Then shift-drag or shift-click images you'd like to export:

Start the export
Look in the upper left of the window and click the down-arrow export button:

Choose a resolution

Wait for the completion dialog box

Copy that message and paste it into a comment below, along with anything that went wrong! Thanks a lot!
Example export
Please include:
- a link to the map
- how many images you exported
- what resolution you chose
- a link to the output
Map: https://mapknitter.org/maps/east-providence-pond-view-map/
- 35 images
- 28 cm/px in about 3 minutes
- Output JPG:** https://mapknitter-exports-warps.storage.googleapis.com/1585682284/1585682284.jpg
List of big maps you can test out (from this list):
- [ ] https://mapknitter.org/maps/lemon-fair-burn - ~30 images
- [x] https://mapknitter.org/maps/lincoln-peak-vineyard has 48 images ~3mb each!!!
- [ ] https://mapknitter.org/maps/scott-test-bienvenue is quite large
- [ ] https://mapknitter.org/maps/otter-view-park-west also huge
- [ ] This is a tough one with 2 map areas far apart. It'll probably fail due to being too big a TIFF: https://mapknitter.org/maps/ile-perrot-1947-49
https://mapknitter.org/maps/lincoln-peak-vineyard/
- 24 cm/px
- 48 images, 3mb each
- https://mapknitter-exports-warps.storage.googleapis.com/1585683543/1585683543.jpg (~3000x2000)
Running last one again - https://mapknitter.org/maps/lincoln-peak-vineyard/ - at 10cm/px, in same open window...
IT WORKED! ~7000x5000 px output, @ ~5mb:
- 10cm/px
- 48 images, 3mb each
- https://mapknitter-exports-warps.storage.googleapis.com/1585684810/1585684810.jpg
Now trying at 5cm/px 😅
This breaks my browser, but... it worked @ 15mb: https://mapknitter-exports-warps.storage.googleapis.com/1585685256/1585685256.jpg (14000x10000px)
it also generates a 543mb tif at: https://mapknitter-exports-warps.storage.googleapis.com/1585685256/1585685256.tif
OK, so, noting that while exporting works, there seem to be some inconsistencies on local saving of export status:
- [ ] https://mapknitter.org/maps/the-mews/edit gave an alert upon completion but did not save status of most recent export within the Rails app (stuck at 2 of 22)
- [ ] i think this may be because we are fetching the status differently in these two blocks of code? We should be relying on the remote
status.jsonfile: https://github.com/publiclab/mapknitter/blob/b085f654b6c117d72979570b382f75dbafb2f129/app/controllers/export_controller.rb#L51-L82 - [ ] AHA! the interface shows a link to https://export.mapknitter.org/id/1586280820/status.json, but the ajax request shows https://mapknitter-exports-warps.storage.googleapis.com/1586280820/status.json -- and these show different values!!! We probably need to be flushing a cache, maybe? or updating the address once we get the first response, to be the direct to
https://mapknitter-exports-warps.storage.googleapis.comversion?
Wow, @icarito doesn't see the discrepancy but noting here i saw a discrepancy on both browser downloads and wget
OK so we can bypass by:
you can bust the cache by adding a GET parameter as in
https://export.mapknitter.org/id/1586280820/status.json?a=<timestamp>
let's do this
https://github.com/publiclab/mapknitter/blob/b085f654b6c117d72979570b382f75dbafb2f129/app/views/maps/_cloud_exports.html.erb#L15
I suppose this ought to do it: export_url + "?cachebust=#{rand(1000)}"
https://github.com/publiclab/mapknitter/commit/8e20d25ffd975a1f2e769a8730cc2591b24da081 - made the change here! I did it in JS
Confirmed it worked... not 100% sure it busted the cache but it ought've -- we'll publish to production to confirm in a sec...
Confirmed!
OK, haha i think i reached the limit: https://mapknitter.org/maps/2011-08-06-brooklyn-newtowncreek-north
13960x20698 px
1.15589GB
2020-05-07 22:18:28 +0000
stalled at making a JPG from that 1.15GB GeoTiff 😂
Oh! What can we do? do we know where it failed?
Logs should be at https://console.cloud.google.com/logs/viewer?project=public-lab&resource=gae_app%2Fmodule_id%2Fdefault
El vie, 8 de may de 2020 a las 10:45, Jeffrey Warren [email protected] escribió:
OK, haha i think i reached the limit: https://mapknitter.org/maps/2011-08-06-brooklyn-newtowncreek-north
13960x20698 px
1.15589GB
2020-05-07 22:18:28 +0000
stalled at making a JPG from that 1.15GB GeoTiff 😂
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Oh wait that is for the app itself not the exporter...
It probably ran out of memory? I mean, imagemagick will crash with a gigantic enough image. I think not super high priority as it's probably beyond the limit of what we'd want to support. 13k x 20k pixels is a TON.