Re: [OpenMap Users] Newbie questions....

From: JR Andreassen <>
Date: Thu, 27 Jul 2006 15:35:21 -0500

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 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
> 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
>> (
>> 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" ?

Can you make a projection that is relative to the "current possition"
with no refresh until you reach a certain offset from the edge ?

> 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.....

> 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...


JR Andreassen
Strategic Database Inc.

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Received on Thu Jul 27 2006 - 16:35:52 EDT

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