Hello Again...
I've created a Layer for DB/2 Geospatial Extender...
I based it on the mySQL version.
It works, but it is so slow that it's not usable.
Two problems:
1) WellKnownText conversion is way too slow.
2) It refetches all the objects from the DB every time.
So, is there a caching Layer object I could inherrit from instead of
OMGraphicHandlerLayer?
Has anyone done anything with WellKnownBinary ??
Thanks
JR
>
> On Jul 27, 2006, at 4:35 PM, JR Andreassen wrote:
>
>> Thanks for getting back to me.
>>
>>>> Issues so far:
>>>> How to you specify the base map ?
>>>
>>>
>>>
>>> You would configure a layer to display the data you want. For the
>>> default OpenMap application, the layers are specified and
>>> configured in the openmap.properties file. That file has
>>> instructions for modifying itself.
>>>
>>>> I can't find any reference on where to change the base map Image.
>>>> (Or is there a way to specify a Shape/other as the background)
>>>>
>>>> Does it /How do I handle Quadrangle/TIFF images ?
>>>
>>>
>>> The easiest way to display images is to use the
>>> CSVTiledImagePlugIn. The JavaDocs for the CSVTiledImagePlugIn
>>> describe how to create a CSV file that list the images and their
>>> locations, and the plugin can be added as a layer to the
>>> application (via the openmap.properties file), with that csv file
>>> noted in the properties for that plugin.
>>> I'm not sure if TIFFs are handled by the general JRE, come to
>>> think of it. You might have to install the JAI package (Java
>>> Advanced Imaging) to get TIFF functionality.
>>
>>
>> I can handle that...
>>
>>>> Does it /How do I handle Segmented data and transitions?
>>>> We have several datasets that we'll be based on
>>>> (http://www.capcog.org/Information_Clearinghouse/ geospatial_main.asp)
>>>> These data sets(roads, etc) are split into areas(counties) since
>>>> they are rather large.
>>>
>>>
>>> Shape files can be read to create OMGraphics, which are the
>>> objects rendered to the map. They know how to position and
>>> render themselves. There are Layers that create OMGraphics out of
>>> Shape files, and one (MultiShapeLayer) that handles more than one
>>> Shape file. If you are going to have a lot of data...
>>>
>>>> Does it /How do I handle monster datasets ?
>>>
>>>
>>> you should load the data sets into a database (MySQL, PostGRES
>>> with PostGIS, Oracle) and use a layer to retrieve the geometries
>>> from the database based on the projection.
>>
>>
>> Newbie question: Is the projection your subset of the world vs
>> "zoom-factor" ?
>
>
> The projection is a description of the map window - there's a
> projection type associated with the object, a center point of the
> projection at the center of the window, a scale, and pixel height/width.
>
> Projection's forward() methods translate lat/lons to pixel
> coordinates, and inverse() methods translate pixel coordinates to lat/
> lon coordinates.
>
> The MapBean (the main map window object) controls the Projection
> object and lets its layers know when it has changed.
>
>> Can you make a projection that is relative to the "current
>> possition" with no refresh until you reach a certain offset from the
>> edge ?
>
>
> You can change the projection on the MapBean whenever you like. The
> layers are reactionary to the MapBean's notifications. If a layer
> needs to change the projection, it has to tell the MapBean.
>
>
>>> A MySQL layer is part of the distribution, and an
>>> OracleSpatialLayer was posted to the mailing list and is available
>>> in the archives.
>>
>>
>> The DB approach is appealing to us, since we have a DBM(DB/2) on
>> each machine. The problem with the DB/2 GeoSpatial extender is that
>> it's $9k per machine.
>> Given that we have over 2K users that's way outside our budget. So,
>> is there a X./Open standard for GeoSpatial data ?
>> I might be able contribute some in that area.....
>
>
> The Open GIS Consortium (OGC) has a standard for storing data in a
> database, Simple Features for SQL.
>
> I don't know if there is an open source DB2 geospatial extender, or
> if you want to add one of the other free databases to your machines
> to handle large amounts of spatial data.
>
> - Don
>
>
>
>
>>> Does it /How do I handle Lat/Lon to Layer serches ?
>>> If you are using a database with large datasets, it's probably
>>> better to do the search on the database. You can also work with
>>> the OMGraphics to do spatial searches for those objects rendered
>>> on the map.
>>>
>>> There's a developer's guide available at:
>>
>>
>> Got that one...
>>
>>> Hope this helps,
>>
>>
>> It does indeed...
>>
>> Thanks
>> JR
>>
>> JR Andreassen
>> Strategic Database Inc.
>>
>> --
>> [To unsubscribe to this list send an email to "majdart_at_bbn.com"
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>
>
>
>
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> Don Dietrick, dietrick_at_bbn.com
> BBN Technologies, Cambridge, MA
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>
>
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>
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Received on Mon Jul 31 2006 - 21:07:14 EDT