# Worldmap loads colour map before greyscale

**URL:** <https://discourse.nodered.org/t/worldmap-loads-colour-map-before-greyscale/72455>\
**Category:** General\
**Created:** [20 December 2022 09:40 UTC](https://discourse.nodered.org/t/worldmap-loads-colour-map-before-greyscale/72455 "2022-12-20T09:40:32Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![rmwiseman](https://avatars.discourse-cdn.com/v4/letter/r/e47c2d/32.png) [@rmwiseman](https://discourse.nodered.org/u/rmwiseman)\
**Post date:** [20 December 2022 09:40 UTC](https://discourse.nodered.org/t/worldmap-loads-colour-map-before-greyscale/72455/1 "2022-12-20T09:40:32Z")

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In my Worldmap instance, I've got "OpenStreetMap Greyscale" and "ESRI Dark Grey" in the map list, and the first of these is my base map.

I don't know if it's a quirk of Leaflet or something to do with Worldmap itself, but I've noticed that when it loads map tiles, it always seems to load OpenStreetMap ones (NB: that's "OpenStreetMap", **NOT**"OpenStreetMap Greyscale") first and then the "OpenStreetMap Greyscale" ones over the top of them, even though "OpenStreetMap" isn't even selected in my map list. It's quite distracting, especially over a slower connection when zooming or scrolling.

Anybody have any idea why it's doing this, please?

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**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\
**Post date:** [20 December 2022 11:07 UTC](https://discourse.nodered.org/t/worldmap-loads-colour-map-before-greyscale/72455/2 "2022-12-20T11:07:32Z")

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I'm not really sure - but it may be because the greyscale is actually just a filter applied to the colour one - ie it processes each tile to turn it back into greyscale - so on slower devices it has to load the tile first then process it, and this is visible. (I'm not 100% sure but ...)

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**Author:** ![rmwiseman](https://avatars.discourse-cdn.com/v4/letter/r/e47c2d/32.png) [@rmwiseman](https://discourse.nodered.org/u/rmwiseman)\
**Post date:** [20 December 2022 12:57 UTC](https://discourse.nodered.org/t/worldmap-loads-colour-map-before-greyscale/72455/3 "2022-12-20T12:57:25Z")

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Thanks @dceejay, I think you might be right, looking at the network activity. I'm not seeing any greyscale images loading at all, although rather bizarrely it does (on a different map that has both colour and greyscale enabled) reload some colour tiles when changing from colour map to greyscale map! It's a shame it doesn't convert them to greyscale and _then_ display them, but at least it's minimising the time taken to display the tile this way.

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**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\
**Post date:** [20 December 2022 13:15 UTC](https://discourse.nodered.org/t/worldmap-loads-colour-map-before-greyscale/72455/4 "2022-12-20T13:15:17Z")

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it saves having two sets of tiles... and in theory can be applied to any WMS map source.

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**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [3 January 2023 13:15 UTC](https://discourse.nodered.org/t/worldmap-loads-colour-map-before-greyscale/72455/5 "2023-01-03T13:15:59Z")

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