kucai's diary

Recent diary entries

Survey points etc

Posted by kucai on 30 June 2020 in English (English)

I have been registering surveyed points from the RTK gps units that I used at work. Usually, I updated those references to JOSM’s image offset database, used to be both for Bing and Maxar. Lately however, I just uploaded data for Bing only.

Part of the reason is that I found that Maxar has quite a lot skewy images despite their recentness. Their images are also at a different zoom level than Bing, so providing offsets for both Maxar and Bing seems to be pointless. Older Bings were nicer, but newer ones seems to be the same image used by Esri and Maxar, so they are equally good (or bad).

To overcome the different zoom scale of the imageries, I always defaulted to the ‘corrected’ Bing. In areas where new roads/developments can be seen only in Maxar, I will offset Maxar to Bing. I’d find a house closeby, trace it in Bing, and then move Maxar imagery to match. Hopefully, everything will remain consistent. Well, at least until new (paid/unpaid) mappers started tracing and aligning everything to Maxar that is..

I am still undecided regarding gps tracks. Quite a few issues: bad signal (resulting bad accuracy), kalmann filter, not enough traces covering x-y axis. Better than nothing though. I’d rather prefer a 10 minute averaging (or median value) gps position.


So much help!

Posted by kucai on 1 April 2020 in English (English)

Top ten fifteen mappers in my country are not even locals. There’s a need to form a new rebel alliance! We shall rise, silently and slowly. Currently, we are just tired.

Location: Cahaya SPK, Subang, Shah Alam, 40170, Malaysia

Paid mappers

Posted by kucai on 6 September 2019 in English (English)

I am beginning to think that it is a mistake to include paid foreign mappers to help map your cities. They are creating as many imaginary roads as our country’s road department it seems. And yeah, they are incapable of drawing a straight line with just two nodes…

Location: Damansara Heights, Kuala Lumpur, 50490, Malaysia

Dual freq GPS and map alignment

Posted by kucai on 29 July 2018 in English (English)

With the introduction of dual freq chip from Broadcom, and the maturing firmware on Mi 8, the possibility of 30cm accuracy becomes much closer to mappers (hopefully standalone receivers are in development too). How are you guys planning to deal with this? Do you think there will there be a map alignment wars? Will iD incorporate that imagery offset db plugin like in JOSM? Do we go nuts with different imagery having different lens zoom ratio on the same zoom layer and having align both to a unified offset?

The OCD in me wants to align everything precisely, but I sure appreciate the Soviet’s approach of “good enough”.

Much welcomed DigitalGlobe imagery

Posted by kucai on 12 June 2017 in English (English)

I have just explored the newly available Digitalglobe imagery around Malaysia, and was blown away with its coverage after all these years waiting for Bing. It was almost orgasmic! Not to mention the few that I worked with aligned almost exactly with my gps tracks, right in the middle of the road. Very happy, despite finding some sort of distortion (wavy terrace houses) with the imagery. Perhaps that could very well be caused by the unserviced surveyor’s theodolite during the housing area survey & marking stage.

Then it dawned on me..all those areas to be traced. That’s a seriously a huge amount of work to be handled by a handful of OSMers around here. Going to need a couple hours dedicated to tracing everyday whenever possible, starting with the important features first : streets in cities and towns, then following up with residential areas and the like.

Nevertheless, thank you Digitalglobe!

p/s anybody had trouble with JOSM (ver12039 here) acting up? At one point, text input doesn’t work anymore, but mouse actions work (pressing buttons & stuff). Just wondering although my Opensuse Leap 42.2 laptop isn’t that top notch either - btrfs, kde plasma & memory are possible issues. Maybe it is my laptop… anyways…. peace out.

Mapping lake shore

Posted by kucai on 7 August 2016 in English (English)

I started refining the shore boundary of Lake Kenyir, reputedly the largest (or 2nd?, not sure, another lake is being filled up in Sarawak) in South east asia. Soon enough, I realized that there are jillions of coves that might need to be mapped, which brings the question of what’s the acceptable level of fidelity when dealing with this kind of mapping. (this would certainly the case when mapping a country’s shorelines too.)

I finally ended up using the ‘triangle’ method. 2 points at the jutting land ends of a cove (which is also called a point in bass fishing:) ) and 1 in the middle of the cove. If that is still too rough, add a point to either side of the middle point, which usually is good enough to show up as a cove in higher zoom renderings.

Oh well.. I probably need to visit these places with fishing gear.. you know.. verification purposes and all that. hah!

Location: Hulu Terennganu, Terengganu, 21700, Malaysia

Aligning hiway to Bing imagery

Posted by kucai on 30 December 2015 in English (English)

Just finished aligning the northern half of Jabor-Jerangau highway (about 50km) to newly available Bing imagery. Since the highway was originally created based on a gps track (I think), there was quite an offset between the gps track and Bing.

Also in some areas, it seemed that hiways on Mapbox imagery lay much closer to accumulated gps track than Bing, but that can possibly be attributed to the difference between coarse level 17 zoom to Bings level 18/19 color imagery. Bing is about 20-30 meters away from gps tracks.

I think I’ll wait for more gps tracks before I offset the imagery. For now, I’ll focus on making pretty highways…

Thank you Bing.. need moarrr…

Location: FELDA Jerangau, Terengganu, Malaysia

Potlatch editing

Posted by kucai on 16 December 2015 in English (English)

Crap, changeset creation error after 30 minutes tracing riverways in Paka

Rage… Fuuu*88

*damn, I always forget to save periodically even after I reminded myself to save periodically. And periodically, this happened

New sat image and alignments

Posted by kucai on 3 September 2015 in English (English)

Partially finished realigning buildings in Kota Bharu, Malaysia. It seems that a new sat image was available, and a mapper(s) traced the highways according to the new image but leaves the outline of buildings from older image intact. Therefore, those buildings have to be moved manually by selecting each one of them to align with the new image. (ignore lat long accuracy for the moment).

Perhaps, anyone who discovers an area with new sat image should first align existing hiways/buildings. Once the hiways/buildings matched with the new sat image, only then the sat image & hiways & buildings be offset to the accurate position. (can also be done the other way around, align the image to the existing highways/buildings, whichever is more accurate). That way we don’t have to align things two or three times manually. (Anyway, anybody knows how big an area is offset when we realign a sat image? One tile, 10sqkm, whole state?)

Or perhaps, people should try not to accidentally realign the map (new mappers especially).

Central Kuala Lumpur

Posted by kucai on 23 December 2014 in English (English)

I had to take the bus to the city center and back yesterday. While searching for the correct boarding locations (3 different locations within a kmsq), I noticed quite a lot has changed. During the wait for the arrival of the return bus, I wished that my ver 1 galaxy tab has the processing power to run vespucci to do on the spot corrections. Vespucci used to run & edit, but nowadays it runs without showing maps & data from osm anymore, only a black screen. Need to start saving for upgrade I guess (or win a lucky draw somewhere).

BTW, any of you visiting my country are more than welcomed to help map that area. :) (our currency is devaluing right now, more bang for your money!)

Location: Bukit Bintang, Kuala Lumpur, 50200, Malaysia

No Waiting

Posted by kucai on 14 October 2014 in English (English)

I am getting tired fixing the automated notes. For every river crossing, some darned program will put a river name note. For every overpass, it will put no waiting on both sides of the bridge. Then there is the “Go ahead” notes popping up here and there.

Luckily, our main North South highway is only few hundred kilometers long. God help me if it is as long as I-40…

Location: Kampung Senta, Teluk Intan, Perak, Malaysia

Mapbox satellite view experiment

Posted by kucai on 14 August 2014 in English (English)

Been trying to get more zoom than just level 17 with iD and Potlatch. I tried using browser zoom view, which is quite usable for Chrome and Mozilla, but doesn’t work with IE. It didn’t work with Potlatch either, the satellite view remained constant regardless of browser zoom level.

Also, using iD on 19in monitor with max browser zoom, will leave about 2 inches of vertical editing area. To get best alignment, I left out the tagging process for later so that I get to trace with thin lines instead of the fat iD highway line types.

It was a slow process. I’ll rather wait for better imagery (or JOSM implementation of iD zoom interpolation) for those areas, which we’ll probably get in 3 years. Hopefully!

Location: Taman Temerloh Jaya, Temerloh, Pahang, 28000, Malaysia

Senarai lokasi masjid

Posted by kucai on 27 June 2014 in Malay (Bahasa Melayu)


Aku ada jumpa senarai masjid/surau untuk daerah hulu langat yang siap lengkap dengan gps koordinit (lari sikit dari lokasi sebenar, kadang2 kena search keliling baru jumpa kubah masjid), nama masjid, nama kampung dsbnya. Baru sempat siap dalam 20 lokasi gitu, maklum le bila download area sekitar point guna JOSM, kawasan keliling pun touchup sikit2. Guna shift-D, copy paste koordinit, zoom out sikit hingga skala kat atas kiri skrin tunjuk dalam 50meter, lepas tu klik download to current data layer.

Lepas tu aku call diorang, katanya kat JAIS ada senarai untuk seluruh Selangor. Haa… terbeliak mata nak siap, tapi insyaAllah pahala banyak wooo…