Re: [OpenMap Users] Please help, newbieOpenmap to display Street information

Hi Steve,

On Feb 5, 2004, at 11:10 PM, Pang Kwong Yiu wrote:

> Dear all,
>
> I am using openmap to develope a web application.
>
> Do anyone know how can I use openmap to show street information like
> street name
> and other locational information? Which component of openmap can I use
> to
> display those information together with map? And do I need to use a
> database in
> this application actually?

You would start by using/writing a layer to draw the streets. If you
have Shape data, you can use the
com.bbn.openmap.layer.shape.ShapeLayer, or the
com.bbn.openmap.plugin.esri.EsriPlugIn. Their javadocs have more
detail. You can use a database if you want, but depending on the
database you might have to change the layer a bit. The
com.bbn.openmap.layer.mysql package has components that display
contents from a MySQL database. The paradigm is the same for other
databases, but you might have to change the components that read
database output to create OMGraphics for rendering on the map.

Street names would be displayed using OMText objects. In Shape files,
the street names are usually in the .dbf file, and you associate the
name with the street geometry in the .shp file. OpenMap classes
already create OMPoly objects out of the .shp contents, you'd just have
to add the part of creating OMText objects for names, and placing them
appropriately based on the OMPoly locations.

> What's more, which database is most of the openmap developers
> currently using?
> And widely support?

I'm not sure what the answer is to this question.

>
> In addition, how can I put the text information in a layer and the map
> in
> another layer and output these 2 layers to image when the user click a
> position?

For an image served to a browser, or for an applet? What kind of web
application? You can certainly have the different information in
different layers, and each layer can respond to mouse events. There
are entries in the FAQ providing more guidance for setting up OpenMap
for web applications.

> Sorry that I have so many questions, and I have tried my best to study
> the
> openmap but I am still confused and don't know where to start.

I'd start with the example applications, with the OpenMap application
and with the examples in com.bbn.openmap.examples, as well as the
advice in the FAQ.

- Don

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