[GeoNetwork-devel] User defined symbology

hello

i’m working on an implementation of geonetwork that renders wms layers to the map - once a few have been rendered (taking their colour from the wms service) it becomes harder to differentiate them (although layer opacity can be changed) - one possible solution might be to allow users to set layer colours.

from initial observations, it looks as it this might need to take place at the point that openlayers renders to canvas, any ideas or recommendations?


joe

https://maplondon.ml/

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Depending how you want to implement, in general the point of WMS is that the data provider is providing a predrawn layer that is intended to be used as is.

  • A WMS can be setup with multiple named styles, and a user interface can be used to choose between these if available
  • Depending on the WMS service it may allow you to pass inline SLD with the requested fill color. In this case your web application is taking over, but the rendering is still going to occur on the server side
  • You may be able to play with some special effects on the images once they are available in openlayers as individual ImageLayer layers.
  • I assume this tutorial https://openlayers.org/en/latest/examples/color-manipulation.html is simiilar to what you would like to achieve?
  • One technique I enjoyed when working on a desktop client was to use opacity to fade out every layer execpet the currently selected layer. If you are providing a legend you could turn this into a hover effect as the mouse passes over each legend entry.
···


Jody Garnett

interesting, the hue adjustment in the openlayers demo you provided should work well for differentiation purposes, also i think it will look neat sitting alongside the opacity slider in the gn ui - thanks!

  • the use case here is a planner assessing a given location and pulling in all the various planning restriction zones (polygons) that cover that location.
···

From: Jody Garnett jody.garnett@anonymised.com
Sent: 21 August 2020 07:32
To: Joseph Leach Joseph.Leach@anonymised.com
Cc: geonetwork-devel@lists.sourceforge.net geonetwork-devel@anonymised.coms.sourceforge.net
Subject: Re: [GeoNetwork-devel] User defined symbology

Depending how you want to implement, in general the point of WMS is that the data provider is providing a predrawn layer that is intended to be used as is.

  • A WMS can be setup with multiple named styles, and a user interface can be used to choose between these if available
  • Depending on the WMS service it may allow you to pass inline SLD with the requested fill color. In this case your web application is taking over, but the rendering is still going to occur on the server side
  • You may be able to play with some special effects on the images once they are available in openlayers as individual ImageLayer layers.
  • I assume this tutorial https://openlayers.org/en/latest/examples/color-manipulation.html is simiilar to what you would like to achieve?
  • One technique I enjoyed when working on a desktop client was to use opacity to fade out every layer execpet the currently selected layer. If you are providing a legend you could turn this into a hover effect as the mouse passes over each legend entry.


Jody Garnett

On Thu, 20 Aug 2020 at 10:13, Joseph Leach <Joseph.Leach@anonymised.com…> wrote:

hello

i’m working on an implementation of geonetwork that renders wms layers to the map - once a few have been rendered (taking their colour from the wms service) it becomes harder to differentiate them (although layer opacity can be changed) - one possible solution might be to allow users to set layer colours.

from initial observations, it looks as it this might need to take place at the point that openlayers renders to canvas, any ideas or recommendations?


joe

https://maplondon.ml/

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oh, the legend hover idea is nice too, it would also work on first press for touch interfaces

cheers again

···

From: Joseph Leach Joseph.Leach@anonymised.com
Sent: 21 August 2020 11:15
To: Jody Garnett jody.garnett@anonymised.com
Cc: geonetwork-devel@lists.sourceforge.net geonetwork-devel@anonymised.coms.sourceforge.net
Subject: Re: [GeoNetwork-devel] User defined symbology

interesting, the hue adjustment in the openlayers demo you provided should work well for differentiation purposes, also i think it will look neat sitting alongside the opacity slider in the gn ui - thanks!

  • the use case here is a planner assessing a given location and pulling in all the various planning restriction zones (polygons) that cover that location.

From: Jody Garnett jody.garnett@anonymised.com
Sent: 21 August 2020 07:32
To: Joseph Leach Joseph.Leach@anonymised.com
Cc: geonetwork-devel@lists.sourceforge.net geonetwork-devel@anonymised.coms.sourceforge.net
Subject: Re: [GeoNetwork-devel] User defined symbology

Depending how you want to implement, in general the point of WMS is that the data provider is providing a predrawn layer that is intended to be used as is.

  • A WMS can be setup with multiple named styles, and a user interface can be used to choose between these if available
  • Depending on the WMS service it may allow you to pass inline SLD with the requested fill color. In this case your web application is taking over, but the rendering is still going to occur on the server side
  • You may be able to play with some special effects on the images once they are available in openlayers as individual ImageLayer layers.
  • I assume this tutorial https://openlayers.org/en/latest/examples/color-manipulation.html is simiilar to what you would like to achieve?
  • One technique I enjoyed when working on a desktop client was to use opacity to fade out every layer execpet the currently selected layer. If you are providing a legend you could turn this into a hover effect as the mouse passes over each legend entry.


Jody Garnett

On Thu, 20 Aug 2020 at 10:13, Joseph Leach <Joseph.Leach@anonymised.com05…> wrote:

hello

i’m working on an implementation of geonetwork that renders wms layers to the map - once a few have been rendered (taking their colour from the wms service) it becomes harder to differentiate them (although layer opacity can be changed) - one possible solution might be to allow users to set layer colours.

from initial observations, it looks as it this might need to take place at the point that openlayers renders to canvas, any ideas or recommendations?


joe

https://maplondon.ml/

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GeoNetwork-devel mailing list
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https://lists.sourceforge.net/lists/listinfo/geonetwork-devel
GeoNetwork OpenSource is maintained at http://sourceforge.net/projects/geonetwork

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