[talk-ph] Fwd: RFC: importing Palawan roads

George Tujan gtujan at gmail.com
Mon Jun 8 03:38:14 BST 2009


@maning: i've contacted a former officemate who lives in palawan and
is every interested in joining and contributing at least may palawan
mapper na tayo. :). His name is Jefferson Fermo and he was very
excited when he saw the current state of OSM in the Philippines :)


On Sat, Jun 6, 2009 at 3:13 PM, maning
sambale<emmanuel.sambale at gmail.com> wrote:
> With more eyeballs all bugs are seen (Linus Torvalds)
>
>> Doing a quick check on proportions and shapes of different tracks from different portion of
>> the map, I think the data supplied is trash. :-(
>
> As per Rally's assessment, I am holding-off to importing this data.
> Unless, others can make sense of how we can use this for OSM.  I can
> provide a download link to anyone who wants to play around with it.
> If you think it's useable for OSM, we can discuss this here.
>
> Personally, nanghinayang lang ako, if this is good data (or at least
> useful) a good chunk of roads will be added to OSM.  But as Rally
> said,
>> So, we'll surely get in trouble or lose good reputation for uploading bad data, hehe
>
> I'd rather accept someone saying we have wrong data because of an
> honest newbie experimenting around than importing data we know having
> big problems.
>
> Thanks Rally for doing the assessment.  Any other comments?
>
>
> On Sat, Jun 6, 2009 at 11:49 AM, Eugene Alvin Villar<seav80 at gmail.com> wrote:
>> I was about to ask you to ask them how they compiled their data. It
>> obviously wasn't traced over Google Earth nor taken using GPS tracks. I
>> think Rally might have guessed their method correctly.
>>
>>
>> On Sat, Jun 6, 2009 at 11:26 AM, maning sambale <emmanuel.sambale at gmail.com>
>> wrote:
>>>
>>> ---------- Forwarded message ----------
>>> From: Rally de Leon <ralleon at gmail.com>
>>> Date: Fri, Jun 5, 2009 at 9:36 PM
>>> Subject: Re: [talk-ph] RFC: importing Palawan roads
>>> To: maning sambale <emmanuel.sambale at gmail.com>
>>>
>>>
>>> Doing a quick check on proportions and shapes of different tracks from
>>> different portion of the map, I think the data supplied is trash. :-(
>>>
>>> I've seen shape files very much like this (like the one I obtained
>>> from Taytay Assessor) that was just traced over TAX MAPPING paper
>>> sheets (purely based on shape guestimation and visual
>>> ratio-and-proportion) then converted then to autocad drawings. I've
>>> seen them how they draw the lot shapes on paper (during the time
>>> nagtatambay ako sa assessor). It's doable if you know where to chop
>>> the areas (eg. per subdivision or per purok), then convert it back to
>>> raster image, then georectify that image (for every area) which will
>>> need actual gps waypoints, then trace your vector lines over the
>>> raster layer. But what's the point? we are talking of the whole
>>> palawan.The purpose of this data is just for assessment and for
>>> assigning PIN codes on the tax declaration, not for navigation nor for
>>> making proportionally correct paper map.
>>>
>>> I highly doubt that the data came from actual field survey. Because
>>> I've traced Namria topo maps before (in Luzon datum), and they were
>>> proportionally correct when I translated them to WGS84. My old
>>> personal garmin maps were made this way with fairly high degree in
>>> accuracy. But in this case, the shp file have wrong proportions,
>>> different shapes, different angles, a lot of extraneous lines and
>>> streets (that doesn't make sense), really bad. I tried Luzon-Mean,
>>> Luzon-Philippines, Luzon-Mindanao (all failed), so I tried to cheat by
>>> just dragging them over google satellite image, still failed, won't
>>> fit. No wonder you can't make it fit using all available datum, hehe.
>>> nadaya yata tayo dun. If we are lucky enough to have one subdivision
>>> fit the roads of a satellite image (yahoo or google), the adjacent
>>> subdivision won't (as i've tried it since this was really easy to do
>>> in trackmaker pro). In my experience, even those subdivisions as far
>>> as 500meters from your reference tracklog should still fit the
>>> satellite image with your extended vector traces; in this case, even
>>> the neighboring streets a few blocks away doesn't.
>>>
>>> So, we'll surely get in trouble or lose good reputation for uploading
>>> bad data, hehe. I suggest we just recruit gps-tracker volunteers in
>>> any of the streets in palawan (where there are good hi-res satellite
>>> images), and lets do it the old fashion way.
>>>
>>> Call back the source of this data and ask him to confess (if they
>>> really made that survey). kung ayaw umamin, i-torture natin ;-D
>>>
>>>
>>> On Fri, Jun 5, 2009 at 6:17 PM, maning sambale
>>> <emmanuel.sambale at gmail.com> wrote:
>>> >
>>> > I tried every projection parameters I can think of pero may shift pa
>>> > rin, anyway the shift is systematic so moving the whole data to fit
>>> > existing OSM roads, should be straightforward.
>>> >
>>> > Here's the data, around 7 MB:
>>> > http://esambale.wikispaces.com/file/view/palawan_roads.zip
>>> >
>>> > Tirahin mo sya!
>>> >
>>> > On Fri, Jun 5, 2009 at 6:01 PM, Rally de Leon<ralleon at gmail.com> wrote:
>>> > > can you send me a copy of this palawan tracks? how big? i'm sure you
>>> > > already
>>> > > have your methods of converting to wgs84.
>>> > >
>>> > > but let me see what i can do (para meron naman akong mapaglibangan
>>> > > this
>>> > > weekend). don't worry, i'm not going to trace over googleearth. (lets
>>> > > just
>>> > > compare notes later) :-)
>>> > >
>>> > > i'm just going to try if it's as easy as shifting the entire thing on
>>> > > the
>>> > > built-in datum-shifter of GPS trackmaker, if it works and passed our
>>> > > counterchecks,
>>> > > then the data goes to JOSM for additional validations, edits and
>>> > > tagging.
>>> > >
>>> > > else if it's not that easy, maybe we can use a method of shifting
>>> > > arbitrary
>>> > > control points. (most likely, palawan is on Zone 2 of Luzon Datum,
>>> > > then
>>> > > convert to WGS84) (practically, all main Luzon island is on Zone 3 -
>>> > > the one
>>> > > used by surveyors). The alignment of these "luzon-datum tracks" to the
>>> > > "computed WGS84 control points" can be done entirely within JOSM by
>>> > > just
>>> > > dragging the entire tracks. We have many ways to check the accuracy
>>> > > afterwards. medyo barok (as we will use graphical method - JOSM's is
>>> > > very
>>> > > good at this), but it may work without the need to for mathematical
>>> > > conversions and without the need to rely on googleearth alignments.
>>> > >
>>> > > On Fri, Jun 5, 2009 at 2:51 PM, maning sambale
>>> > > <emmanuel.sambale at gmail.com>
>>> > > wrote:
>>> > >>
>>> > >> > There is no online map we can compare the traces to to see how
>>> > >> > accurate
>>> > >> I'm doing it when I got this message. :)
>>> > >>
>>> > >> See for yourself over GEarth (blue is OSM, red is the road data).
>>> > >> http://farm4.static.flickr.com/3566/3596753363_51c00bb5f3_o.jpg
>>> > >>
>>> > >> Notice the shift?
>>> > >>
>>> > >> (copyright image of DigitalGlobe and Google included to abide by it's
>>> > >> Terms of Use) :)
>>> > >>
>>> > >>
>>> > >> On Fri, Jun 5, 2009 at 2:18 PM, Andre
>>> > >> Marcelo-Tanner<andre at enthropia.com>
>>> > >> wrote:
>>> > >> > There is no online map we can compare the traces to to see how
>>> > >> > accurate
>>> > >> > it is?
>>> > >> >
>>> > >> > _______________________________________________
>>> > >> > talk-ph mailing list
>>> > >> > talk-ph at openstreetmap.org
>>> > >> > http://lists.openstreetmap.org/listinfo/talk-ph
>>> > >> >
>>> > >>
>>> > >>
>>> > >>
>>> > >> --
>>> > >> cheers,
>>> > >> maning
>>> > >> ------------------------------------------------------
>>> > >> "Freedom is still the most radical idea of all" -N.Branden
>>> > >> wiki: http://esambale.wikispaces.com/
>>> > >> blog: http://epsg4253.wordpress.com/
>>> > >> ------------------------------------------------------
>>> > >>
>>> > >> _______________________________________________
>>> > >> talk-ph mailing list
>>> > >> talk-ph at openstreetmap.org
>>> > >> http://lists.openstreetmap.org/listinfo/talk-ph
>>> > >
>>> > >
>>> >
>>> >
>>> >
>>> > --
>>> > cheers,
>>> > maning
>>> > ------------------------------------------------------
>>> > "Freedom is still the most radical idea of all" -N.Branden
>>> > wiki: http://esambale.wikispaces.com/
>>> > blog: http://epsg4253.wordpress.com/
>>> > ------------------------------------------------------
>>>
>>>
>>>
>>>
>>> --
>>> cheers,
>>> maning
>>> ------------------------------------------------------
>>> "Freedom is still the most radical idea of all" -N.Branden
>>> wiki: http://esambale.wikispaces.com/
>>> blog: http://epsg4253.wordpress.com/
>>> ------------------------------------------------------
>>>
>>> _______________________________________________
>>> talk-ph mailing list
>>> talk-ph at openstreetmap.org
>>> http://lists.openstreetmap.org/listinfo/talk-ph
>>
>>
>>
>> --
>> http://vaes9.codedgraphic.com
>>
>
>
>
> --
> cheers,
> maning
> ------------------------------------------------------
> "Freedom is still the most radical idea of all" -N.Branden
> wiki: http://esambale.wikispaces.com/
> blog: http://epsg4253.wordpress.com/
> ------------------------------------------------------
>
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