[OpenLayers-Dev] ESRI and OpenLayers
Christopher Schmidt
crschmidt at metacarta.com
Tue Mar 10 21:16:19 EDT 2009
On Tue, Mar 10, 2009 at 01:03:44PM -0600, Tim Schaub wrote:
> Hey-
>
> David Zwarg wrote:
> > Greetings community,
> >
> > One thing to note for the ArcIMS and ArcXML patches: they are a best
> > effort to implement the most commonly used functions in ArcXML. This
> > includes get image and get feature requests.
> >
> > Anyone who's looked at the ArcXML specification knows that it's very
> > thorough, and supports a myriad of operations. The ArcXML support in
> > the patch mentioned implements image requests and feature requests.
> > However, there are limits to what is implemented. The entire ArcXML
> > schema is not replicated in the ArcXML patch, so it's not a complete
> > port. As with most projects, the current patch satisfies the business
> > need that I have with the resources that I have.
> >
> > I am willing and able to be the custodian of that component, but will
> > need more feedback from users of the ArcIMS layer for advanced
> > operations (geocoding, projection (have you heard of this proj4js
> > library?), etc.).
>
> Count this as a tentative offer to help review stuff and get it in the
> trunk. We (OpenGeo) are interested in Arc* support in OpenLayers as well.
>
> I'll follow up on the ticket(s) when we've got the back end stuff set up
> for testing.
I'm taking on ArcIMS at the moment; I should have a reviewed patch
within the next day.
> Tim
>
> >
> > Thanks,
> > z
> >
> > On Sun, Mar 8, 2009 at 10:03 AM, carls <carlshe at 163.com
> > <mailto:carlshe at 163.com>> wrote:
> >
> >
> > I had tested
> > 'root/sandbox/dzwarg/openlayers/lib/OpenLayers/Layer/ArcIMS.js'
> > and 'root/sandbox/dzwarg/openlayers/lib/OpenLayers/Format/ArcXML.js'
> > with
> > OL2.7. It works well.
> >
> > I hope and would like to see the support of ArcIMS in OL2.8, if
> > possible.
> >
> > Thanks.
> >
> >
> > Christopher Schmidt-2 wrote:
> > >
> > > Eric,
> > >
> > > Your email led me into a response that is really far more
> > appropriate to
> > > the entire dev list in my opinion. ESRI and OpenLayers is a
> > particularly
> > > large hole in the library support, and I wanted to really get
> > down a lot
> > > of my thoughts on why this is. Please take all this with a large
> > grain
> > > of salt as being my personal point of view... but perhaps not an
> > > entirely-inaccurate one, given my level of involvement in the
> > project.
> > >
> > > On Mon, Mar 02, 2009 at 04:27:21PM -0700, Eric Wolf wrote:
> > >> Christopher,
> > >>
> > >> I hate to open old wounds, but I'm preparing a presentation centered
> > >> around generating a tile cache consumable by OpenLayers but based on
> > >> an ArcGIS map layout. I've tried some different configurations:
> > >
> > > So, I want to start off by saying this: No existing OpenLayers core
> > > contributor has, in any major way, a personal or professional
> > motivation
> > > towards supporting ESRI's web services, so far as I am aware. This
> > > includes the OpenGeo community (generally speaking, tightly
> > coupled with
> > > GeoServer), the Camptocamp group (which works almost exclusively
> > outside
> > > the realm of ESRI, as far as I've observed: possibly motivated by
> > > Europe's lack of proprietary buy-in, hooray), or the DM Solutions
> > > (primarily around MapGuide, and MapServer) or MapGears (primarily
> > around
> > > MapServer) contributors. I expect that if you came with $$ to any of
> > > these groups, they would be likely to be able to help you, but
> > it's not
> > > so common of a problem to make it worthwhile for them to spend time
> > > maintaining ESRI-specific code without a customer asking for it.
> > >
> > > With that in mind, almost all work on ESRI-related developments
> > thus far
> > > has been by non-core contributors to the project, and OpenLayers has,
> > > in some cases, not had a great track record with non-core
> > contributors
> > > of content doing the work to get their code in trunk.
> > >
> > > The ESRI AGS code developed thus far has been prey to this: several
> > > people have used it, but not:
> > >
> > > * Documented it
> > > * Tested it
> > > * Created examples for it
> > >
> > > As such, the code is not something that the OpenLayers community can
> > > support without a strong leader stepping up and taking on the task on
> > > the code.
> > >
> > > Some counter-examples to this are:
> > >
> > > * The recently committed ArcGIS 9.3 REST API layer.
> > > * The in-review ESRI ArcXML layer.
> > >
> > > Both of these sets of code have had committed developers who have
> > > written tests, provided documented examples, etc. in clean, well-laid
> > > out patches.
> > >
> > > Based on your problem description on the mailing list --
> > something you
> > > neglected to include in this email, which makes it difficult to
> > respond
> > > to precisely -- I can not describe what the best solution is for you,
> > > based on my personal knowledge. I don't use any ESRI products or
> > > anything else.
> > >
> > > Though I don't know if it's the best thing for your use case, I
> > do feel
> > > that it would be beneficial to the OpenLayers community to have
> > access
> > > to ESRI's map caches. Cached map tiles are clearly much faster than
> > > non-cached map tiles, and the recent developments of ESRI's -- making
> > > available, for example, sampleserver.esri.com
> > <http://sampleserver.esri.com> or whatever it is -- make
> > > this type of development much simpler.
> > >
> > > However, to accomplish this goal, there still needs to be a
> > champion of
> > > the task -- someone who is reasonably experienced in Javascript, and
> > > willing to step up and take on the task of providing the OpenLayers
> > > community with the support it needs to get this support into the
> > > library. This means that, for example, documentation and examples
> > would
> > > need to be written, etc. and the contributo would likely need to
> > > demonstrate some willingness to continue to support developers in
> > > maintaining the code, since none of us are, as far as i know,
> > > particularly well-versed or highly motivated to maintain the code
> > at a
> > > reasonable level of quality on our own.
> > >
> > > You proposed a number of possible solutions:
> > >
> > >> * Turning on WMS in ArcServer and pointing TileCache at it.
> > Works but
> > >> ArcServer wants to serve the layers independently, so I get back to
> > >> the SLD problem.
> > >
> > > To me, this seems like a configuation issue. That is, the WMS serves
> > > layers individually, but they're typically possible to combined, with
> > > something like:
> > >
> > > layers=0,1,2
> > >
> > > In your TileCache config. However, I only know very little of ESRI's
> > > software, so I can't comment on that for sure, and I haven't seen any
> > > links that help me look at your setup to confirm-or-dis-confirm this
> > > notion of mine.
> > >
> > >> * Generating a tile cache out of ArcServer and kludging TileCache to
> > >> serve it up.
> > >
> > > I don't know what 'ArcServer' is, but I expect that this would have
> > > essentially the same problem that has existed i ArcGIS caches in the
> > > past, which is that most people who have access to caches don't know
> > > what the parameters used to create the cache are.
> > >
> > >> And lastly:
> > >>
> > >> * Pulling the AGS plugin for OpenLayers out of the sandbox
> > >
> > > This code should probably be in trunk, as described above. The
> > fact that
> > > it is not is because no sufficiently motivated Javascript
> > developer has
> > > made it so. (As Mr. Schaub pointed out at one point, these things
> > arent
> > > meant to happen magically; in Open Source, you need to either pay
> > > someone to do it, or do it yourself.)
> > >
> > >> I haven't actually tried the last bit because of some of your emails
> > >> I've found from 2007. It sounds like AGS is a dead-end. Is this
> > true?
> > >> Is there a specific reason?
> > >
> > > AGS is not a dead-end, but you probably read emails where I was
> > > expressing my frustration, centered mostly around the stuff above.
> > > Specifically, the same problem as there is in many aspects of the
> > > project has arisen here:
> > > * Someone writes some code
> > > * The code is insufficient, poorly documented, or simply 'not done'
> > > * The author of the code expects it to get in trunk
> > > * Requests to do more work to make it happen are ignored.
> > >
> > > The general assumption in these cases seems to be that if someone
> > writes
> > > some code, it will automatically be in trunk, which is simply
> > > unrealistic. OpenLayers is a high quality code library, and it seems
> > > completely reasonable to me that in order to keep it that way, we
> > have
> > > to maintain some standards. However, this means that some code
> > does not
> > > make it into trunk in a timely manner, and the patch authors feel
> > > shunned or ignored. Although this is almost always not the case, the
> > > emotions there are very frustrating as a developer: the
> > expectation that
> > > patches lead to changes in the library 'for free' is just unfair
> > to the
> > > core development team.
> > >
> > > In this case, I was unable to st up the ArcGIS cached layer code
> > to talk
> > > to any server I could find documented on the web. If I an't do it, I
> > > can't imagine that most users can do it: I'm a pretty smart guy in
> > > general. If I cant' pull it off, then it is probably the case that
> > > others can't either, and that means that putting it in trunk is
> > asking
> > > for pain. With that in mind, I saw no significant personal benefit to
> > > working on it, and the code has sat.
> > >
> > > My expressed frustration is/was probably unfair. I'm not aware of any
> > > problem with the code as it exists -- except that people are
> > using it,
> > > and not giving back to the community by trying to get it into
> > trunk. I
> > > find that combination extremely unfair, given the amount of work
> > that so
> > > many people put in to make the library possible. I'd love to see some
> > > organizations out there who are using this code really invest in
> > it, and
> > > make the library better for everyone as a result. This could come
> > in the
> > > form of paying developers to work on it, project sponsorship with a
> > > stated request -- though not binding, clearly somewhat motivating
> > -- or
> > > other potential venues. Without any of this kind of support,
> > > organizations -- of which there are several -- using the AGS code are
> > > simply taking from the library, and not giving back. that type of
> > > behavior is frustrating to me, and that has probably come through in
> > > previous emails.
> > >
> > >> And input would be greatly appreciated.
> > >
> > > Using ESRI services in OpenLayers needs champions -- people who are
> > > willing to truly support the cause. ArcXML has a champion in the
> > form of
> > > dzwarg, who has been working with me on an ArcXML ticket. ArcGIS rest
> > > layer had a champion in the form of Jeff Adams. AGS cache needs the
> > > same. The community could probably rally up and make this support
> > > happen: lots of people have expressed interest. Open Source isnt all
> > > about things being done for you, and I'd love to see some of the
> > users
> > > of the software really invest in OpenLayers more than they have up to
> > > this point. ESRI-specific services are a great example of this, where
> > > there's a lot of code floating about, but relatively limited
> > support of
> > > it outside of the companies using it or specific use cases, and
> > that's
> > > a great example of what I'd love to see change.
> > >
> > > Sorry for using you email as a jumping off point for a 'rant'
> > like this,
> > > but the state of ESRI-in-OpenLayers is an excellent example of what
> > > *feels* like poor community support of library in favor of immediate
> > > needs, and I really like the idea of that changing. (And if I'm
> > > completely ignoring a significant effort in this regard, this is a
> > > perfect oppourtunity for the existing community members whose work I
> > > have been ignoring to step up and tell me how wrong I am!)
> > >
> > > Regards,
> > > --
> > > Christopher Schmidt
> > > MetaCarta
> > > _______________________________________________
> > > Dev mailing list
> > > Dev at openlayers.org <mailto:Dev at openlayers.org>
> > > http://openlayers.org/mailman/listinfo/dev
> > >
> > >
> >
> >
> > -----
> > Regards, Carl SHE
> > --
> > View this message in context:
> > http://n2.nabble.com/ESRI-and-OpenLayers-tp2412861p2444558.html
> > Sent from the OpenLayers Dev mailing list archive at Nabble.com.
> >
> > _______________________________________________
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> >
> >
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>
> --
> Tim Schaub
> OpenGeo - http://opengeo.org
> Expert service straight from the developers.
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--
Christopher Schmidt
MetaCarta
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