Zoom of raster map

bongo · December 05, 2011, 11:38:24

i just generated my first rastermap (pixelmap in .tar format).
seems to work fine on locus, but i'm not able to zoom.
when using multitoch to zoom in/out, the map zooms, but as soon as i take my fingers off the display, it goes back to original size.
also the zoom buttons on the bottomline are grayed out.
what am i doing wrong / what do i have to do to be able to zoom rastermaps?
thanx!

Menion · December 05, 2011, 11:52:53

hi bongo,
you created one layer tar map file. This file can have only one level (and that's why you see greyed zoom buttons). You can anyway re-raster this map by pressing last button on bottom panel (zoom lock) which then allow to zoom in/out (only a little) in selected one layer ...

bongo · December 05, 2011, 12:00:13

thanx, great!

i generated this map using ozimaptrans. do you know if there's a way to generate multilayer maps to have a wider zoom range?
thanx!

Menion · December 05, 2011, 12:13:10

I don't know this software. But when you generate more tar maps of same region in different zoom levels, try to name them in correct order like map01.zip, map02.zip, etc ... and place them into one subdirectory of locus/maps directory. This should work then as multi-layer map

bongo · December 05, 2011, 14:10:12

hm. didn't get that working...
what else tool do you recommend to generate raster maps for locus?

Menion · December 07, 2011, 19:58:15

why this do not work?? It have to work ...

bongo · December 07, 2011, 20:27:23

i tried again with other raster maps of the same region and named them ch1.tar, ch2.tar, ch3.tar and ch4.tar. i placed 'em directly under locus/maps.
after loading a map, i can zoom within this map when pressing zoomlock first, but there's none of the other maps loaded.
so i renamed them ch4.tar, ch3.tar, ch2.tar and ch1.tar to check if the order has impact, but it does not work either.
i have no idea what i'm doing wrong...

Menion · December 07, 2011, 20:51:09

i wrote and place them into one subdirectory of locus/maps directory

so put them for example to locus/maps/my_own_multi_tar_map_that_works_for_sure/chX.tar ...

bongo · December 07, 2011, 22:49:40

sorry, i misunderstood!
i thought that means that the maps can be in any directory below locus/maps.
now it works ;-)
thanx a lot!

bongo · December 08, 2011, 11:47:44

so now, autoloading of rastermaps with different resolutions works, but the next problem already appears...

while i have a 1m and a 200k map for a region, the 25k map is split into 4 subregions.
by adding a _1 to the 1m map, a _2 to the 200k map and a _3 to the 25k maps, only one of the 25k maps seems to be instantiated. no matter in which part of the region i am, it always loads the 1st one of the 25k maps when switching to a higher resolution, no matter if this map covers the actual centerpoint.

so now, i merged the 4 25k maps to a single map, resulting in a .tar file of 2.7gb.

while android can see this file, it does not show up in locus.

is there a file size limit in locus?
how much is this?

what workaround can be used? i.e. is there a way to use more than 1 file of the same resolution or how can i make this work?

thanx!

bongo · December 10, 2011, 14:20:17

i played around a bit more with these maps, but still see no way to use the autoload feature for maps with different resolutions, because:
for moving to a region, i usually take a low resolution map (maybe 1:1'000k), and when i'm there, i zoom in and get the 1:200k for better positioning. when i found the right region, i switch to the 1:25k.
but of course, the better the resolution, the more map tiles are required (still was no able to load maps with more than 2gb into locus, they are not shown).
so if locus is not able to detect which tile of the higher resolution map is lying under the actual position of the low resolution map, it's not very useful, although it seems to be a good idea at a first glance.
so i see two ways to solve this:

approach based on actual solution:
locus generates an index database after scanning all the map files. then it knows what areas are covered with which map and which resolution. then whenever switching map towards lower/higher resolution, it takes the next map which covers the actual center of the actually shown centerpoint of the display.
in addition, searching can be limited to the actual folder.

alternative approach:
use an index database too, but do not autoswitch map. there is a button 'search map for actual position' which shows up all maps which cover the actual centerpoint of the display, and their resolution, for manually select the apropriate map. (this seems to be a bit less complicate and is the way ozi explorer (on win / win ce) works).

what do you think about?

bongo · December 13, 2011, 11:02:58

there are still a few open questions from the posts above (and a few more):

- what is the file size limit for .tar map files?
- is there a tile number limit within a .tar file?
- what is the preferred tile size within a .tar map (is 256x256 the best)?
- how can i handle switching between different resolution maps, if more than 1 high res map is used to cover the area of one low res map?
- are there any plans for alternative features for map selection (see post above) for better handling of maps covering areas of different size?
- is there a way to store maps in subfolders without using the autoload-on-zoom feature (i.e. allows to select the individual map instead of only the folder when manually selecting a map)?
thanx!