I wrote the following comments in June while on a long flight and have been meaning to send them to the list.
Also now that I realize massgis has a wms in mass state plane with 15cm
color orthophotos, I want to be able to switch to that coordinate system
and use it.
----------------------------------------
I've been starting to use viking and have a few comments and
suggestions. I am finding the program very useful, so please don't
interpret my comments as negative. I would like viking to work better
offline; it's already pretty reasonable. I'm writing this from
running viking 0.9.8 on a Mac (built from pkgsrc), but I also use it
on NetBSD. I don't know when I'll have spare time to implement any,
so I thought I'd send the suggestions to the list in case anyone finds
them useful. Priority comments are about where I'd put in time - I
certainly don't expect others to write code I want unless of course my
suggestions make them want that code too.
* I know I'll probably be told to run from CVS/SVN instead of 0.9.8,
but if that's the right advice a release is overdue.
* I'd like to have a preset standard set of map layers and be able to
invoke viking on a gpx file. Basically in this use case I want to
use viking as a viewer and not create a viking file to manage
waypoints - I just want map underlay behind my tracks and waypoints
so I can look at them. I don't mind a different command, but I'd
like to basically do 'viking-osm 20090601.gpx' and have a viking
window come up with the waypoint/track layer on top with osm tiles
under it. This is perhaps equivalent to having a file with just
maps and running "viking maps.viking --merge foo.gpx", with the
caveat that the gpx has to be on top.
[This is what I would work on first; it would make the default issue
not so important because I could set up the file once. I realize I
can open a file and the open/merge the gpx file.]
* The default zoom and pan choices when opening a gpx file do not
seemto make sense. The scale says 500m, and zoom 4 (z15), and the
position seems to be the middle of the bounding box. For a GPX file
of A->B on highways, the resulting view had none of the trackpoints.
My preference is to zoom to track, and I suppose zoom to waypoints
if there are fewer than some number of trackpoints. I see a center
on layer option, but nothing to adjust zoom. When opening a GPX
file with waypoints, the center appears to be the center of the
waypoints, and because I haven't yet deleted the all import Garmin
US/Europe/Taiwan, that's someplace not all that interesting (with
apologies to those at 38N 13E :-). I can only zoom out to 8192,
which is I think z4. So it's awkward to get back to the US (I
realize I can goto a waypoint). Why can't I see the global-scale
tiles?
* I would like map layers to default to saving tiles someplace
standardized and sensible, and to autodownload. I realize that not
everyone will feel this way, but I think most people will. I save
tiles in ~/VIKING/MAPNIK for osm mapnik tiles. I realize the whole
issue of cache purging and max size is hard, but I think that's
separate from the question of defaulting to save tiles. Perhaps a
single global preference to save tiles should cause map layers to be
configured to save tiles and maybe autodownload.
* Deal better with failed downloads. viking should be more prepared
to have no or flaky net access, including captive proxies at
airports. If it doesn't get a valid PNG file or some other valid
tile data, it shouldn't create a cache file. Cache files of zero
length should be removed when noticed.
* Show tiles from cache before waiting for downloads to fail, if
downloads have been failing. Perhaps an offline mode to use cache
only would be 99% of the value with a lot less work.
* Keep a log of tiles that were requested when offline and be able to
fill the cache when online. Needs some kind of rate limiting to
avoid being abusive. Perhaps waiting longer of 1s or the last tile
service time between requests would be ok.
* It would be nice to have Some other kind of cache filling support,
perhaps various scales around waypoints and tracks, but this seems
fraught with perils, both in terms of server abuse and privacy
issues. Definitely low priority.
* From the above two comments obviously I need the planet dump and a
tile server on my laptop and will get to that at some point; there's
no reason not to have the data with me. But the map layer add
dialog doesn't have a custom URL. Maybe a localhost standard place
where osm people normally put their local tile server would be a
good thing to add to the defaults, plus having arbitrary URLs.
* I was confused about how to create a new track/waypoint layer (that
I'd want to export separately). I generally find the map layer
names confusing, and I wrote the following while trying them
all.. Probably this is my fault but a few things would help:
in apple-click properties menu, give the layer type explicitly.
aggregate layer should have a null properties dialog maybe. I
think it's just a container for other layers so you can turn its
children on/off all at once.
"Coord" layer might be better named "grid lines". In 'mercator'
mode (which is really "google spherical mercator" - perhaps put
the EPSG code in the menu :-)), it seems to be natural to have a
1' grid. When I flipped to UTM (which I think is various zones,
NAD83 or WGS84, to line up with terraserver tiles, but not 100%
clear), the grid still seemed to be in minutes. That's a useful
option, but in the US on UTM maps from USGS grid lines are in the
UTM grid, every 1 km on 1:25K maps. The coord layer obviously
autoscales (which is good), but there's no clue what it's doing.
For GeoRef layer, datum should be specified. It's fine for
viking to be WGS84 only, but when asking for map parameters this
should be clear. (In the US, scanned topos that are in NAD27 are
fairly common.) It would be nice to have a way to make a world
file and offer to write it alongside the map, and to have the
normal mode of operation be to associate a world file when a map
doesn't have it, and then use world files. That would make it
easier to share the registration work among users. But this is a
nit and I'd put it at low priority.
In map layers, the default name is "Map" which is not useful.
For OSM (mapnik), I'd like the default name mapnik, and I bet
everyone else would too.
In GPS layer, it's not clear what "data mode" does. realtime
tracking mode obviously talks to gpsd, which makes sense.
On the DEM layer, it seems like the normal thing is to download,
but it seems these should be cache too - but it's not clear how
to do that.
So now I understand that TrackWaypoint is the layer type, and when
you open a gpx you get a trackwaypoint layer named after the gpx
file name - which is just fine.
* When zooming, I easily got confused before I got used to how tile
scales work.
In the bottom info line, show the zoom level somehow, and show it
in red if it's not supported by any tile server being shown. Once
I figured out that the maps just vanish when you zoom in too far,
I learned not to. <pause to try more options> So now I see that
the zoom scale in the bottom is somehow relative to the most
detailed OSM tiles. But it's a multiplier from z17, it seems, and
I don't understand why it says "2.000/2.000..."
Mapnik tiles are stored in t13s0z0 for what seems to be the z17
tiles. I don't understand why there are called s0 instead of z17,
and what the s0 is for. I would think there is nothing special
about the max zoom level - that's just an artifact of that
particular mapnik installation in choosing the conventional max.
I would prefer names that tie very closely to what I would expect
are the WMS parameters, but I could well be confused here.
Given the t13, it seems 13 is code for osm/mapnik, and I see 13 in
the .viking file. If the map name is encoded in the file, we
don't need subdirs for the default tile cache directories.
When zooming in too far, it would be nice to duplicate pixels of
the z17 or whatever the most zoomed in level available for that
WMS is, instead of not showing anything.
In Mercator mode, zoom levels seemed locked to the standard zoom
levels for spherical mercator. This seems sensible, but the zoom
level option in map with values and "use viking zoom" confused
me. Probably this is just me.
* Obviously viking makes network requests, such as WMS tile fetches.
There are privacy issues associated with this, but that's
unavoidable. Having an offline mode would be nice for this; perhaps
a globe icon that's default depressed and when not (like sidebar)
causes viking to omit all network requests.
* Besides OSM tile fetches, it seems there is 'upload to OSM' and
'show wikipedia points'. Presumably the wikipedia points creates a
wikipedia layer, but I haven't tried it. For both of these, it's
obvious what will happen. The option to search by name is less
clear. Viking doesn't have a names database, so presumably it
queries the net for this -- but that is not at all clear.
* The default keybindings are unnatural and have caused me to do the
wrong thing. ^Q should quit without saving, and ^W close one window
but not the others, just like any other program. There probably
should be a modified indicator by appending a * in some status
location, and ^S already saves so that's fine. And of course a
discard/save/cancel dialog when quitting with modified data -- ^W
should have that now.
I don't object to a save/quit combo keystroke. But ^Q means quit,
and the user expectation is that this will not write anything.
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