Infinite horizontal scrolling

Oct 27, 2010 at 4:00 PM

Hi guys,

I wonder if there is a mean to display a map with the same behavior as in google maps, i.e. to draw the map continuously along the "horizontal axis".

For instance, with this behavior and the classic world map, i would be able to draw and see a continuous line from a point in Japan to a point in california; over the pacific ocean.

Do you have any idea to achieve this kind of effect ?

Thanks 

Developer
Oct 27, 2010 at 5:28 PM
Occasionally I look at that, and say wow, that sort of effect would really make it nicer for our folks that live near the international dateline. The problem is that we need to be careful that this sort of wrapping only occurs for geographic coordinate systems. Most GIS coordinate systems will not work with this model. For instance, if you had a UTM grid, then it not only won't have values in the range, but attempting to introduce wrapping of any sort would not only be wrong, it would adversely affect the display of data layers.

That being said, the view could be theoretically created by tiling the full -180 to 180 extent horizontally. Google also introduces the very slick globe spinning momentum calculation. It really feels like you are spinning a globe. I love that effect, but I'm not entirely sure if it works well in non-globe circumstances.

An internal MapFrame could be used essentially without changes. What would be different would be the map control that wraps it, and tiles the image correctly, shifting it as necessary, but in the MapFrame internally, just using the map frame to draw the entire -180 to 180 span once, and then using bitmap tiling in the OnDraw method for the map. A new "momentum panning" MapFunction would have to be created if the "spinning the globe" option was desired.

That being said, I think this is a bell or whistle that is not as urgent as our existing bug fixes. But you could add it as a proposed feature request, because if enough people vote on it, we could upgrade the request to being more important.

Ted


On Wed, Oct 27, 2010 at 9:01 AM, oliv135 <notifications@codeplex.com> wrote:

From: oliv135

Hi guys,

I wonder if there is a mean to display a map with the same behavior as in google maps, i.e. to draw the map continuously along the "horizontal axis".

For instance, with this behavior and the classic world map, i would be able to draw and see a continuous line from a point in Japan to a point in california; over the pacific ocean.

Do you have any idea to achieve this kind of effect ?

Thanks

Read the full discussion online.

To add a post to this discussion, reply to this email (DotSpatial@discussions.codeplex.com)

To start a new discussion for this project, email DotSpatial@discussions.codeplex.com

You are receiving this email because you subscribed to this discussion on CodePlex. You can unsubscribe or change your settings on codePlex.com.

Please note: Images and attachments will be removed from emails. Any posts to this discussion will also be available online at codeplex.com