Manifold supports several ways of performing spatial DBMS work with Microsoft SQL Server:
· Microsoft SQL Server 2008 (codenamed Katmai) - This new Microsoft product will provide spatial support using native spatial DBMS capability like other spatial DBMS packages such as Oracle Spatial or IBM DB2 with Spatial Extender. Manifold Enterprise Edition and higher editions have built-in capability to work with native SQL Server 2008 spatial capabilities, including both GEOMETRY and GEOGRAPHY data types. As of this writing, Microsoft has released a spatially-capable Community Technology Preview (CTP) for free download by the public. Manifold will track new Microsoft CTPs as they are released and will continue to support SQL Server 2008 spatial when it is released to the public. SQL Server 2008 will be the first choice for spatial DBMS work in the SQL Server community. See the Example: Configuring SQL Server 2008 topic before working with a SQL Server 2008 CTP.
· Microsoft SQL Server 2005 with Manifold Spatial Extender - Manifold has created a spatial extender for SQL Server 2005 to enable users to work with SQL Server 2005 as a high-performance spatial DBMS until SQL Server 2008 is released. The Manifold spatial extender utilizes Manifold geometry and Manifold spatial indices with a small amount of code that is uploaded into the SQL Server 2005 server for execution server-side. The uploaded code enables SQL Server 2005 to achieve better performance than a purely generic use of spatial indices. The Manifold Spatial Extender also works with SQL Server 2008; however, if we have SQL Server 2008 we should use SQL Server 2008's spatial capabilities. Note: When used with SQL Server Express 2005 the Manifold Spatial Extender requires SQL Server Express 2005 SP2.
· Microsoft SQL Server with Manifold Generic Spatial Index - This applies to SQL Server 2000 and more recent SQL Server editions such as SQL Server 2005 and SQL Server 2008. Because SQL Server, like almost every other big-name DBMS, provides binary storage we can use Manifold's generic, non-native spatial DBMS capability within SQL Server using whatever Manifold-supported geometry type we like (such as Manifold's Geometry or OGC WKB) together with Manifold-created spatial indices. This usage of SQL Server is just as we would use any other ordinary DBMS, such as MySQL, as a spatial DBMS through Manifold-managed spatial facilities. For performance reasons, with SQL Server 2005 it is always a better idea to use the Manifold Spatial Extender for SQL Server than to use generic spatial indices. Manifold generic spatial indices also work with SQL Server 2008; however, if we have SQL Server 2008 we should use SQL Server 2008's spatial capabilities.
· Microsoft SQL Server 2005 with ESRI SDE - ESRI products can utilize a SQL Server 2005 installation to host an ESRI SDE geodatabase. If SQL Server 2005 hosts an ESRI SDE geodatabase Manifold can connect to that ESRI SDE geodatabase and import and link drawings using ESRI conventions. It is possible for SQL Server 2005 to be used by ESRI products to host Personal geodatabases as well, in which case Manifold can also connect and work with that geodatabase like the SDE case. However, as of the present writing ESRI Personal geodatabases are usually encountered only in the form of Access .MDB files and only rarely using SQL Server, where SDE appears to predominate.
Manifold can store images and surfaces in SQL Server 2008 and SQL Server 2005.
SQL Server 2008 Geometry Types
SQL Server 2008 spatial capabilities include support for two native geometry types: a planar GEOMETRY type similar to the geometry types used by other spatial DBMS products and a geodetic GEOGRAPHY type. The internal workings of either type have not been documented by Microsoft as of this writing, so Manifold uses these types the same way as it does SDO_GEOMETRY from Oracle Spatial.
That is, when data is brought in from SQL Server native GEOMETRY or GEOGRAPHY storage by importing or linking a drawing it is dynamically cast into Manifold Geometry type. When a Manifold drawing is exported into SQL Server, Manifold Geometry is automatically cast into SQL Server native GEOMETRY.
Any edits or other operations performed on SQL Server native GEOMETRY or GEOGRAPHY drawings that are linked into Manifold are dynamically manipulated so that whatever is done in the Manifold session is correctly updated within SQL Server native storage. Any re-projection required to show a linked SQL Server native GEOMETRY or GEOGRAPHY drawing within, say, a Manifold map in a different projection will automatically be done on the fly.
Note that Manifold can import or link a drawing from either SQL Server native GEOMETRY or GEOGRAPHY but that exports from Manifold will always be exported into SQL Server native GEOMETRY. Exports are not available into SQL Server GEOGRAPHY.
If you have a drawing that uses SQL Server GEOGRAPHY Manifold will be happy to use it. You can import it or link it into Manifold. If you link it into your Manifold project, Manifold will happily allow you to edit objects in it, to delete them, to create new objects and so forth. But Manifold will not create a new drawing for you within SQL Server that uses GEOGRAPHY. This limitation arises from the unique nature of the GEOGRAPHY type and may be relaxed in future versions. For the time being, it is not in any way a limitation for GIS operations since GIS data at the present time is universally planar in form, such as the SQL Server GEOMETRY type.
It is also possible that should Microsoft document either the GEOMETRY or GEOGRAPHY type Manifold will add these as intrinsic types that can be held in storage outside of SQL Server, much as can OGC WKB be used in the form of the Manifold Geometry(WKB) type.
SQL Server 2008 Projections
The GEOGRAPHY type always uses Latitude / Longitude. Importing or linking a drawing from SQL Server 2008 that uses GEOGRAPHY type will import or link the drawing into Manifold using Latitude / Longitude projection.
Note for programmers: At the present writing, SQL Server 2008 GEOGRAPHY type is unique in that it uses (latitude, longitude), that is (Y, X), ordering instead of the (X, Y), (longitude, latitude) ordering that is universally used by all other spatial DBMS and GIS products and essentially all other vector and raster GIS formats, including SQL Server's own GEOMETRY type when storing Latitude / Longitude data. When importing or linking GEOGRAPHY, Manifold will automatically swap coordinate ordering into the (X, Y) order expected by all other systems, including Manifold. Programmers writing data directly into SQL Server 2008 GEOGRAPHY type should be aware that the SQL Server order is reversed both from conventional practice and from GEOMETRY type as well.
When reading and writing spatial data stored on SQL Server 2008 spatial using Microsoft's GEOMETRY type, Manifold represents coordinate systems using EPSG codes. EPSG, the former European Petroleum Survey Group organization, has been absorbed into the International Association of Oil and Gas Producers (OGP), but the database of coordinate systems is still widely known as EPSG. EPSG comprises one of the largest vendor-neutral, unambiguous and expertly-developed sets of coordinate systems known. Using EPSG with SQL Server 2008 spatial GEOMETRY is a great way of eliminating the confusion one might encounter with proprietary methods of specifying coordinate systems.
Although EPSG codes cover very many coordinate systems, because Manifold can handle a much larger set of projections than those covered by EPSG, it is possible that a drawing in Manifold uses a coordinate system (projection) not available in EPSG. For example, EPSG does not have a code for Orthographic projection.
If a Manifold drawing uses a coordinate system not supported by EPSG, when the drawing is exported into SQL Server 2008 GEOMETRY, Manifold will re-project it on the fly into Latitude / Longitude form (using EPSG code 4326). Built-in Manifold coordinate systems include all EPSG coordinate systems so that drawings imported or linked from SQL Server 2008 GEOMETRY need never be re-projected for use in Manifold.
SQL Server 2008 spatial allows third parties to choose some other coding method to represent coordinate systems instead of EPSG. If some third party application has used some other coding scheme then Manifold will not be able to automatically detect the correct coordinate system in use, and the correct coordinate system will have to be specified using the Edit - Assign Projection dialog after the drawing is imported or linked into Manifold.
Re-projection in SQL Server 2008
Note that although Manifold will happily re-project data as necessary and can even re-project on the fly so that drawings stored within SQL Server 2008 using different projections can be used together for spatial analytics such as topology overlays, as of the present writing SQL Server 2008 does not have server-side re-projection capability. This means that the usual Manifold facilities for changing projections of drawings stored in spatial DBMS won't work if native SQL Server 2008 spatial enhancements are used. We can, however, still use Administrator Console (available in Database Administrator edition or Ultimate edition) to examine the projections in use.
Launching the administrator console we can connect to SQL Server 2008 using the data source that is configured in the example topics below.
We press the Columns button in the console's toolbar to turn on the Projection column if it is not already visible. This reports the projection in use by drawings. We choose a drawing, a version of the standard Mexico example, that has been uploaded to SQL Server 2008 spatial storage using an unusual projection, MTM Zone 3. We double-click into the projection cell for that drawing.
The Projection dialog used with EPSG codes reports the details of the projection in use. We can scroll down to EPSG 4326 and click on it to highlight it. We can try to re-project by pressing the OK button.
However, we cannot modify the projection (coordinate system) in place.
If we want to re-project the drawing this is easy to do in Manifold: import the drawing into Manifold, re-project it within Manifold, and then export it back into SQL Server 2008.
The Manifold Spatial Extender
The Manifold Spatial Extender for SQL Server is a free extension module for SQL Server which provides spatial index functionality for Manifold System. The Manifold spatial extender works with all versions of SQL Server starting with SQL Server 2005. Always make a point of installing the Manifold spatial extender on the server machine whenever using SQL Server 2005 as a spatial DBMS.
Although the Manifold spatial extender works fine with SQL Server 2008 as well, normally we would use native SQL Server 2008 spatial capabilities instead of installing the Manifold spatial extender and using generic Manifold spatial capabilities.
See the Manifold Spatial Extender for SQL Server topic for details.
SQL Server 2008 Examples
SQL Server 2008 CTP 5 has been used in a series of example topics illustrating work with this fine new Microsoft spatial DBMS product.
Example: Configuring SQL Server 2008
Example: Linking a Drawing from SQL Server 2008
Example: Storing a Drawing in Manifold Spatial DBMS
Example: Storing a Drawing in SQL Server 2008
Example: Tracing Virtual Earth into SQL Server 2008
Example: Storing an Image in SQL Server 2008
SQL Server 2005 Examples
SQL Server 2005 Express has been used in a series of example topics illustrating use of generic Manifold spatial DBMS capabilities. Many of the techniques illustrated (such as use of the Administrator Console) also apply to SQL Server 2008.
Example: Storing a Drawing in Manifold Spatial DBMS
Example: Storing an Image in Manifold Spatial DBMS
Example: Storing a Surface in Manifold Spatial DBMS
0 comments:
Post a Comment