Other spatial database development (PostGIS)

Fri Jul 8 08:00:25 PDT 2005

Read-only OleDB would probably work fine. It would still be some  
effort to implement. Most people really consider read/write the gold  
standard they need for ArcMap, which is why I was focussing on it.

Paul

On 8-Jul-05, at 6:18 AM, uli mueller wrote:

> Paul, why exactly are the signs not promising? Is
> it "only" because OLEDB provides read-only access for ArcGIS? I did  
> not
> really delve into the article you cited, but what I read sounded like
> you can use PostGIS WKBs 1:1 with OLEDB for ArcGIS?? Has anybody  
> successfully implemented read-access from ArcGIS 9 to PG? Would  
> this be only an ugly or also a never-ending hack?
>
> Background: We also have a project where we are constrained to use  
> a personal geodatabase and would be happy to switch to PostGIS.  
> Read-only would be sufficient in this case.
>
> Uli
>
> -- 
> geOps GeoInformatics
> D-79100 Freiburg
>
> Alex Smith wrote:
>
>> I'd like to preface this by acknowledging that my technical  
>> ineptitude may have been the cause of my unsuccessful attempts to  
>> write tabular data to external OLEDB databases from ArcGIS.  And  
>> I'd also like to point out that it's been a while since I tried  
>> doing so - things may have changed.  But my experiences have lead  
>> me to believe that ESRI has (or had) carefully implemented ArcGIS  
>> in a manner that prevents users from writing to external DBMS  
>> without  using ArcSDE.  We do alot of spatial processing that  
>> output and affects a considerable amount of tabular data that many  
>> other rely on and edit where necessary.  Because we're already  
>> pushing the limits of Access, I looked into other options when we  
>> started some new projects....and an affordable option, such as  
>> Postgres or MySQL.  Here's what I found
>>  In the original "Exploring ArcObjects" book, published near the  
>> release of ArcGIS 8.0, states that OLEDB connections to ArcGIS are  
>> read only.  Hence, we couldn't directly output data to an external  
>> table joined to a Access based featureclass.  Sure, we can later  
>> use ADO to update the 'enterprise' database from the Access  
>> geodatabase, but that starts to get messy or becomes, to use  
>> Paul's words, a "moderately ugly hack" (why have the middle-man  
>> Geodatabase tables - like pgArc had the middle-man shapefiles).   
>> So I tried linking in a MySQL table to via ODBC in a  
>> geodatabase .mdb file and attempted to edit that table (no spatial  
>> data) from ArcGIS - I got a message stating that linked tables  
>> cannot be written to.  DAO tables (and I'm fairly certain that  
>> ArcGIS interacts with Access databases using DAO), have a property  
>> that returns true if they are linked tables.   So it seems that  
>> the ArcGIS has code that tests this property and does not allow  
>> users to edit these tables.  I fi
>>
> nd it very
>
>>  hard to believe that this was accidental.  And I later felt naive  
>> for thinking I could somehow 'outsmart' them - ESRI's software  
>> engineers are not dumb.  Expect some resistance in attempting to  
>> circumnavigate their systems.   I understand their need to protect  
>> their investment - the ArcGIS spatial editting tools (including  
>> topology and networks) and ArcSDE must have cost a lot of money to  
>> develop.  And it's good software - ESRI has earned a lot of its  
>> success.  It just sucks for those of us on a limited budget - SDE  
>> licenses on top of commercial RDBMS fees is simply unaffordable in  
>> our case.   On the other hand, ESRI seems to be opening up.  But  
>> they must continue to recover their development costs somehow.   
>> And I'd be surprised if they'd make it easy for other develop  
>> tools to compete with their systems.  Yes, being able to directly  
>> edit PostGIS data using ArcGIS-like editing tools would be  
>> huge....but I don't think that it would be easy and would probably  
>> be cost-prohibitive.  As Paul mentioned, if these things were  
>> easily and cost-effectively attainable, then it probably would  
>> have been done by now.  But then again....look how successful  
>> mapserver has become.  Just my thoughts......
>>  Alex
>> Paul Ramsey <pramsey at REFRACTIONS.NET> wrote:
>> Guys, I am happy to spec this out again, but frankly I fear that  
>> most solutions will remain in the "moderately ugly hack" domain,  
>> ala PgArc. I have investigated more elegant things (oledb) but the  
>> signs are not promising (http://arcgisdeveloperonline.esri.com/  
>> ArcGISDeveloper/ExtendingArcObjects/Ch07/AboutOLEDBProviders.htm).  
>> Principally, the continuing lack of an Oracle Spatial third party  
>> read/write extension on the market says to me that such a thing is  
>> just technically not possible to do attractively. If it were,  
>> someone would have written it by now and be making money on it. If  
>> anyone knows of such a thing, please do tell, it would be a good  
>> positive sign of possible success.
>> Paul
>> On 7-Jul-05, at 10:22 AM, Ken Lord wrote:
>>
>>> Hi Mike,
>>>
>>> This is a major interest to us, we would like to see a push for  
>>> this as well, in fact I was just asked to contact Tyler Mitchell  
>>> about pgArc when I return from my holidays. Tyler! are your ears  
>>> burning? hehe
>>>
>>> pgArc can be found at SourceForge if you want to check it out. It  
>>> has some functionality with ArcGIS 8, but I haven't had it work  
>>> with ArcGIS 9.
>>>
>>> We are locked into personal geodatabases for some of our clients,  
>>> development of a fully functional ArcGIS / PostGIS connection  
>>> would give us a lot more flexibility too.
>>>
>>> Cheers,
>>> Ken Lord
>>> Vancouver BC
>>>
>>>
>>>
>>>
>>> On 7/7/05, Mike Davis wrote: Since we seem to be building some  
>>> momentum on the ESRI personal
>>> geodatabase thing, it seems like a good time to bring up the other
>>> database related item on our wishlist.
>>>
>>> What would be required to allow read/write to a PostGIS database  
>>> from
>>> ArcGIS? I would love the ability to maintain our spatial data in
>>> multiple datbase formats (must me my irrational fear of vendor
>>> lock-in), but unless we can manage the data from within ArcGIS it
>>> isn't really a practical option for us.
>>>
>>> -Mike
>>>
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>
>
> -- 
> geOps GeoInformatics
> D-79100 Freiburg
>