downloading tiles in Maemo Mapper based on a polygon instead of a box
 

i am looking into developing the n810 and Maemo Mapper as a field tool for a number of field staff. The MSVE hybrid data is very very useful to them and in our area, in our case, levels 2 to 4 are the most useful.

the problem is that the geographic area covered by the field staff are such that MSvirtual earth Hybrid tiles at levels 2 to 4 wont fit in the 2 gig limit. if i pre-download maps based on a box (XY upper left and XY lower right), at zoom 4, i end up with allot of unneeded tiles and no room for them to selectively download level 2 for their project sites.

what would be ideal would be if instead of using a box to pre-download if they could upload a GPX file, representing a simple polygon, and download all of the level 4 tiles that fall within that polygon.

Re: downloading tiles in Maemo Mapper based on a polygon instead of a box
 

That would be a nice feature; I'd really like it...

One q&d alternative would be to make a route covering the area to be downloaded (zig-zag or spiral), and download tiles along that route. It's ugly, but it would do it.

Re: downloading tiles in Maemo Mapper based on a polygon instead of a box
 

That was going to be my suggestion, Benson, and in combination with being about to draw routes directly on the map display by using the tap-and-hold menu items, it's almost convenient, even.

But to answer the question, no, Maemo Mapper's "Manage Maps" dialog does not have a "polygon" mode.

Re: downloading tiles in Maemo Mapper based on a polygon instead of a box
 

I have not yet tried the route download feature, and the device is at home now, so can you tell me if i can use a point file with a radius search to download tiles or does it have to be a line file?

Re: downloading tiles in Maemo Mapper based on a polygon instead of a box
 

Not sure what you mean by point file vs. line file, but basically, Maemo Mapper supports the concept of a "route" (which can be downloaded from the internet), which is a bunch of connected points that describe directions from point A to point B. What Benson has suggested is to create a "route" that represents the polygon for which you want to download maps, then use the "Along Route" option in the "Manage Maps" dialog to download maps along that polygonal route. You'll have to fill in the polygon with more route points to download maps for the whole polygon (as opposed to just the perimeter), but it should be possible.

Edit: to clarify: Maemo Mapper downloads all of the maps needed along the route, including the maps that are between two route points. So, for example, you could create a route with two point, one in New York and the other in San Francisco, and Maemo Mapper will download all of the maps in a straight line between those two points. Likewise, your route could be composed of three points in a triangle (plus a fourth point to "close" the triangle), and Maemo Mapper will download maps along the perimeter of the triangle. To "fill" the triangle, you'd have to add route point inside it, either with concentric triangles, or with some other pattern.

Re: downloading tiles in Maemo Mapper based on a polygon instead of a box
 

ill go look at the format for a route file but what i was thinking was for a POI/waypoint file. so for example, that way i could use the POI file for project sites and download level 2 MSVE out to 1 mile from each site.

back to the original topic, for getting the level 4 MSVE data for a general area, and using Benson's method, it seems like i would have to do allot of zigzaging in order to not have any gaps in the interior or the polygon. for level 4 what would be the spacing to use between routes??

i guess another option, which is not as elegant as the download by polygon inside MM, would be to download level 4 for my entire region (winmapper.exe) and then build a seperate utility (qgis, udig, or arcgis) to select the tiles for each polygon area and write them to a MM2.xx db file. but that sounds like allot of work thats mostly over my head right now.

Re: downloading tiles in Maemo Mapper based on a polygon instead of a box
 

You can specify the radius around the path in tiles; the spacing would depend on that. Sorry, but I don't know what the tile size is on any zoom level.

My tendency, having access to CAD software, would be to draw the polygon outline in CAD, and offset it inward by the spacing, not to zigzag. Then connect all the tiers, join them all up, export the point list, and mess with awk to get a gpx file... Really, it'd be a worthwhile project to make a standalone triangle -> path converter, as it's trivial to divide a polygon into triangles (especially a convex polygon), and comparatively simple to make a triangle thing work.

Re: downloading tiles in Maemo Mapper based on a polygon instead of a box
 

This is doable. Just create a GPX file with a trkseg element for each POI, each with a single trkpt. When Maemo Mapper downloads maps along the route, it only "connects" points if they are in the same segment. It should be pretty easy to write an XSL transform to convert a GPX file of POI into a GPX file of single-point trkseg elements.

Re: downloading tiles in Maemo Mapper based on a polygon instead of a box
 

great, if you have a "GPX file of single-point trkseg elements" i can start with as an example that would be extremely helpful. email it to me at tlove@dfg.ca.gov

if i can get an example i will probably just hack out a solution that covers my stuff, so i doubt it will be globally useful so to speak.

Re: downloading tiles in Maemo Mapper based on a polygon instead of a box
 

oh way to much work, i already have the polygons as .shp files and going to GPX is easy. the polys are so large that at level 4 you would easily miss tiles on the interior unless yu created a huge zigzaging file. at the desktop gis end selecting objects that fall within a poly is easy the question would be how to pipe them to the MM2.x database file.

Re: downloading tiles in Maemo Mapper based on a polygon instead of a box
 

You can make your own in Maemo Mapper by just clearing the route, using the tap-and-hold menu to select "Tap Point | Add Route Point", and saving the route via the "Route" menu. It should look something like this: (except i'll add several trkseg elements, so you can see how it should look like with three single-point segments)