[Incubator] FW: SLD Editor

Fri Jun 17 00:01:51 PDT 2016

A bit more background information about the SLD Editor.

I’ve been developing the application for about 18 months as a side project.  The idea started when we did some consultancy work and put together a proposal for an organisation to migrate from an Esri system to an OpenLayers/GeoServer stack. When it came to migrating ~1250 layers we didn’t know what number to put down for symbol conversion to SLD.  When you looked at the numbers this was a large percentage of the overall cost and something needed to be done to reduce it if we were going to be competitive in doing migrations to open source GIS systems.

One of our long standing large enterprise GIS systems required a change to an SLD symbol which we used QGIS to edit. It turned out there was a known bug that caused the change to be forgotten.  I looked to fix it, I’m very familiar with C++ and Qt but found it difficult to debug and realised the SLD styling data model was not completely implemented.

I looked at GeoTools because I knew it could parse SLD files and render them. Another big advantage is that it supports all the GeoServer vendor options, in particular the labelling.  I got something simple working quite quickly and it went from there.

Ideally all this functionality should be in QGIS but QGIS would have to be rewritten to use a C++ version of GeoTools to be able to render the GeoServer vendor options, which will not happen overnight.  We know of people that would love this capability and I understand some peoples reluctance for yet another application.  I think as long as GeoServer is so heavily used a Java desktop SLD Editor application is acceptable.

I’ve had discussions about developing a web-front end for the application, a possibility. However not all GIS systems we deliver are web based and certain projects I work on and locations I work at, do not allow web access or a web server to be deployed without going through a lot of hoops.  If I have a standalone desktop application I can do all my work without having to rely on any other infrastructure.  One of the aims of the application was to be able to work in a connected/disconnected environment, I don’t think all users/developers understand this scenario.

The architecture has evolved. I’ve rewritten parts of it several times, sometimes because it didn’t deliver the right functionality or sometimes because I thought it could be done better (either I had a better idea or trying to improve maintenance), sometimes because I was experimenting.  Some parts of the code definitely need to be cleaned up although some frameworks/interfaces I’ve put in-place I think are quite good.

There will be some work needed to understand why some symbols don’t display. I’m thinking windbarbs where I believe I’m passing the correct data but the symbol is not rendered.

I’m also quite keen to progress the GeoPackage standard supporting SLD files.  I’m not certain whether the standard supports this yet but GeoTools doesn’t let me store an SLD file with a vector dataset that I can pass round in one file.  The SLD Editor has partially implemented this functionality but it would be better if it was a standard and would probably help increase the adoption of the GeoPackage standard.
__________________________________________________________________

Robert Ward
Technical Architect – Enterprise Solutions & Defence
SCISYS UK Limited
T: +44 (0)1249 466575
E: robert.ward at scisys.co.uk<mailto:robert.ward at scisys.co.uk> | www.scisys.co.uk<http://www.scisys.co.uk>

From: Jody Garnett [mailto:jody.garnett at gmail.com]
Sent: 16 June 2016 01:01
To: Robert Ward
Cc: incubator at lists.osgeo.org<mailto:incubator at lists.osgeo.org>
Subject: Re: [Incubator] SLD Editor

Welcome Robert:

That is an impressive project, I was able to checkout, report an issue, and now build :)

There are three ways for projects to get involved in OSGeo:

1. Including your project in OSGeo Live<https://live.osgeo.org/en/index.html> is a great way to reach a wider audience
2. We have set up Community Projects<https://wiki.osgeo.org/wiki/OSGeo_Community_Projects> as an outreach effort for OSGeo providing an easy way for projects to join the foundation.
3. OSGeo Incubation<http://www.osgeo.org/incubator/process/project_graduation_checklist.html> which offers a much closer check into a project's health and wellbeing

aside: Your SLD Editor project is much larger project then your github history indicates, can you tell me anything about the background of the project?

--
Jody Garnett

On 15 June 2016 at 05:30, Robert Ward <Robert.Ward at scisys.co.uk<mailto:Robert.Ward at scisys.co.uk>> wrote:
After presenting at FOSS4G UK, we have released as open source a Java SLD Editor based on GeoTools and think it needs help from the wider open source GIS community.
The source code, user guide and developer’s guide is available here:
https://github.com/robward-scisys/sldeditor
The application is based on the GeoTools library which underpins GeoServer and so has the advantage that all GeoServer vendor options can be dynamically rendered.

Whilst not wanting to duplicate work, this feature is not available in QGIS, which is written in C++ and has a different rendering engine that does not support GeoServer vendor options.

The application is not complete and some areas need to be refactored however I think the application in its current state more than demonstrates what is possible.

There will certainly need to be collaboration with the GeoTools project but in the future with the GeoPackage and SLD standards groups.
__________________________________________________________________

Robert Ward
Technical Architect – Enterprise Solutions & Defence
SCISYS UK Limited
T: +44 (0)1249 466575<tel:%2B44%20%280%291249%20466575>
E: robert.ward at scisys.co.uk<mailto:robert.ward at scisys.co.uk> | www.scisys.co.uk<http://www.scisys.co.uk>

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