OSMers,
It has been ages I been on OSM. I have noted some rivers in OSM has no names despite I created online map for OSMers to pick data and name the rivers. Either way, I will kickstart naming rivers across North-South Highway. It would be good, if someone or many OSMers can start drawing the rivers and I put the naming accordingly, We can work towards complete river coverage goal. I do not have much names for other places in malaysia, so it would be good for others to start putting names in East Malaysia or East Coast Malaysia.
Thanks
perhaps try to get in contact with user mahau, (s)he is into tracing powerlines, rivers and stuff. 
(don’t think he reads this forum)
As for myself, i am more into trying to complete klang valley highway/road tracing (and corrections)… most people are not inclined in trying to trace those numerous housing areas.
I traced some rivers from Bing, but names are not available in the aerial photographs… Hence it is good if you could add the names of the rivers (and also of villages, roads, etc.).
I have recently traced in some rivers for Johore State. Some I have named and other will be named in due time. In view of your comment about names, I have a gazetteer file containing some 60,000 named places in East and West Malaysia. Anyone wishing to make use of this is welcomed to have the file. Its is in csv format showing, name, lat/long, state and coded so that you may extract rivers for Perak state if that is what you want. Just drop me an email.
If any of you are tracing rivers from Google Earth, I also have a KMZ file showing practically all the major river of both East & West Malaysia. The lines are derived from watershed study and so are not accurate. They are however very useful as a guide when tracing as sometime it is difficult to make out faint river lines in satellite images.
FYI - if one is into river tracing and tagging river names, at least (I believe) we have public domain data from US army topo map. Edit: Yup. Quite outdated - use with caution.
For some places, major rivers with its main tributaries should be still unchanged. The rest, well, probably ends up as the so-called lost rivers. Also, if tracing topographical features is your thing, it can be quite useful. Try to compare with Bing / Mapbox imagery.
Here is the list of maps: Malaya AMS Topographic Maps from the PCL Map Collection.
Make your choice, upload to Mapwarper. Rectify (or calibrate), then generate its WMS link. Begin work in JOSM (add imagery). This is the easiest method to make it seen through JOSM (with reasonable accuracy), however, it is not internet-usage-quota friendly :/.
I failed so many times trying manually importing them into JOSM 
Not good at all. GeoTIFF shouts for a worldfile - I need GDAL. Rough picture layer is tricky to make it look right 
PS: let me know if this somehow may lead to legal issues regarding copyrights and stuff
I use globalmapper software to calibrate the raster map.
I use Piclayer plugin to open in JOSM. (importimage doesn’t work for me).
I share the Segamat calibrated JPG in this link : http://1drv.ms/1DLqj0l
Yeah, river in Segamat town center is a bit outdated in the 1940 map, though the main
road’s still the same! 
Tell me what do you think?
I used Piclayer plugin too in JOSM. However, there are only 3 calibration pins (sort of - if you get what I mean). Mapwarper requires a minimum of 3 reference (calibration) pins; but you could add more if you want. That’s why it could be tricky to make the maps look right in JOSM using PicLayer. Perhaps it can be an excellent tool to handle maps within a small area.
FYI - I tried to open your calibrated map, however, I probably have trouble to get the calibration right. The JGW file is meant for calibration, isn’t it? Tried manually to make PicLayer read the file (putting it in the same directory with the map; loading World File Calibration), it is not successful. Instead, JOSM panned me somewhere near 0,0 coordinates.
Didn’t really expect this actually - I thought it could be the other way around! I reckon, the riverbanks must have eroded with time.
Well, if the local satellite coverage is sketchy, the map can be really useful - as a complementary source - with excellent local knowledge and/or surveys. Just my 2 cents.
yes, JGW is the world file, needs to pair up with the JPG to function properly
when open the pic…it kinda zoom to the extent - big black screen
try to pan around or zoom in to Segamat bridge area @ N2.50643 E102.81701.
the raster map should appear.
I guess my copy of JOSM is having some trouble