[josm-dev] Download along track

[Frederik Ramm]

Hi,

    I have finally gotten around to implementing a often-requested 
feature, namely the automatic downloading of data along a given GPS track.

The GPX layer menu has a new entry "download along track" which will 
compute a series of download rectangles along the given GPS track and 
download them for you one after the other.

This feature is still very experimental and I would welcome input and 
programming support. You'll find detailed comments on how it works in 
the GPXLayer class. Some of the issues are:

* buffer size/download size parameter dialog needs improvement
* computing the "hull" of the GPX points takes too long
* when download is running, insufficient information about progress, and 
cancel button does not work

I wonder if we could perhaps also achive a sort of "preview" of the area 
to be downloaded. If we were to give the OSM data layer a generic method 
to cycle through its data sources and re-download them all (this is 
another feature that has been asked for separately - a sort of "refresh" 
function), then we could let the GPX layer create an empty OSM data 
layer that has an array of data sources as computed by the "download 
data laong track" code. That layer could then display the typical 
hatching pattern for the non-downloaded area and would serve as a 
preview of what area you would get if you trigger the download function. 
You can then delete this "empty shell" layer if you're unhappy, or hut 
download to really get the data.

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"