Hi all,
Below is my original posting followed by a summary of responses from
a number of
forums (including esri-l & gis-l). It's certainly given me a lot of
food for thought and generated some additional
questions.
Thank-you to all for the feedback, and I'm sure I'll have additional
material to post as I
further investigate.
Regards,
Mike
--------------------------------------------------
> Hi,
> With Oracle becoming a lot more closely aligned with Mapinfo, I was
> wondering if any out here has had any experience with Oracle
Spatial,
> and how it might compare to the functionality provided by a product
> such as Arc SDE.
> Any info will be appreciated.
> Regards,
> Mike
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Your's is a complex question and depends on the circumstances.
ArcSDE provides the gateway between ESRI�s GIS software and a DBMS
like
Oracle, enabling the DBMS to be used as a central repository for
spatial data. The focus of ArcSDE is GIS data management. As such,
ArcSDE defers as much functionality to the DBMS as possible, taking
advantage of the best technology that each DBMS vendor offers. ArcSDE
is
completely integrated with and supports all the major functions and
capabilities of a spatially enabled DBMS like Oracle Spatial. Where
the
underlying DBMS has no spatial support like Oracle Standard Edition,
ArcSDE will implement all of the spatial functionality.
Here are some considerations:
1.Oracle Spatial is supported on Oracle Enterprise Edition. If
your organization is currently using Oracle Standard Edition , you
can
either move to Oracle Enterprise Edition or either implement a
solution
using ArcSDE's compressed binary format.
2.The advantage of going to Oracle Spatial is that it provides
an open and direct access to the simple feature geometries (points,
lines, and polygons)
using an Oracle supported interface. This means that application
developers and other vendors' products that also support Oracle
spatial
can make use
of the simple features in your spatial database. The benefit here is
interoperability
with other Oracle applications.
3.There are performance differences. Typically, complex GIS
data with many coordinates is slower performing (e.g., retrieval,
query,
etc.) when stored with the spatial types of Oracle Spatial. This has
to
do with a number of functions
including indexing and the way Oracle structures core data types.
Some
of
the performance issues can be overcome by doing a good database
design.
It is also possible to store some of your GIS data in Oracle Spatial
(simpler feature) and, at the same time, store other complex GIS
using
ESRI's compressed binary format. Both of these formats can exist in a
single spatial database environment.
----------------------------------------------------
It is true that ORACLE has a spatial product. Consider that SDE
allows for
the versioning of data to facilitate long term transaction management
and
its support of various spatial operations. ORACLE on the other hand
does
not currently support version management and has rudimentry spatial
capability. ORACLE is working on version management capabilities, but
from
what I ascertain, the product will be lacking when compared with SDE.
ESRI
is far ahead of ORACLE at this point. That may change, but when is
certainly not known and not probable within the next two years. I
don't
actually have the ORACLE spatial product but have researched via
their white
papers and ESRI's development staff.
---------------------------------------------------
It is true that Oracle Spatial performs a similar function to ArcSDE.
If you will be using
ESRI software to access your spatial data in Oracle, then I highly
recommend ArcSDE
since all ESRI software act as native clients to ArcSDE. Just because
Oracle Spatial
can store and manage spatial data doesn't mean your GIS software will
know what to
do with it. If you are using ESRI software, there could be a large
amount of custom
software development (C++, etc.) to make your software use the data.
ArcSDE
provides this for you. Oracle Spatial is OpenGIS certified so the
necessary software
development would be perfectly possible, but probably undesirable.
If you have not settled on the choice of GIS/Mapping software, it is
my understanding
that MapInfo, Intergraph and ObjectFX products use native Oracle
Spatial data.
---------------------------------------------------
We have started working alot with MapInfo and Oracle Spatial. It is a
very
strong implementation. MapInfo reads the data directly with no
middleware
or translation. Everything resides in Oracle. ARC SDE is middleware
resident outside of Oracle.
----------------------------------------------------
Here are some comparative features of ArcSDE and Oracle Spatial that
might help.
ArcSDE
* needs only Oracle 8i DBMS (does not need Oracle Spatial)
* Fast and sophisticated spatial query functions
* Facility to store CAD data (AutoCAD & MicroStation) thro' CAD
client
* Open and published API
* provides powerful data model through Geodatabase
* Has many ESRI Client software
Oracle
* Needs Oracle DBMS and Oracle Spatial
* Needs Enterprise Oracle (Standard Oracle does not work with Oracle
Spatial)
What client software are you going to use to access the RDBMS data.
If
you want to use ESRI clients like ArcView, ArcInfo, MO, etc then
ArcSDE
is the definite choice. By the way, ArcSDE supports Oracle spatial
data
types.
----------------------------------------------------
As I understand SDE's spatial index and objects remain outside of the
main
core of 8i. As a result its performance remains relatively poor. And
while
there is plenty of noise running around about those that claim to be
as
integrated to Spatial as MapInfo this is doubtful.
-----------------------------------------------------
How can any single-RDBMS implementation be "more open"
than ArcSDE?
Oracle Spatial is a subset (a small one) of the capabilities
of ArcSDE and lacks the "enterprise-wide" suite of GIS software to
make the whole thing work.
If you already have ESRI GIS software and Oracle RDBMS,
then finding the right choice among "ArcSDE," "Spatial and
ArcSDE," or "Spatial and new GIS software (and data conversion)"
shouldn't be all that difficult.
------------------------------------------------------
Are you using ESRI GIS products? If so, you will want SDE. I don't
know of any Arc8 or ArcView capability to access data stored in
Oracle
Spatial. (Correct me if I'm wrong on that!) ArcMap, ArcInfo8,
ArcCatalog expect ArcSDE, and do quite a lot with it. I don't think
they understand Oracle Spatial directly. ArcView has capability to
handle SDE connections only, I've seen no hint of ability to contact
Oracle Spatial.
SDE can serve data stored in Oracle Spatial by other apps, provided
they
comply with the Oracle Spatial schema correctly - some don't. SDE can
also store data in Oracle Spatial format, meaning their layer schema
only . SDE apparently does not use the Oracle Spatial indexing or
metadata schema, having its own equivalents. At any rate, that's the
impression I've gotten from my limited experiments with this
combination.
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