Manual data verification through QGIS-GRASS

JUPEM cadaster map

Topology error identified

Zoomed-in

Zoomed further in

Verifikasi data secara manual melalui QGIS-GRASS

Saya amat hormati Jab. Pemetaan dan Tanah, Malaysia (JUPEM) sebagai kustodian peta kadaster negara. Bagaimana pun, kini saya mempunyai mainan namanya QGIS dan ingin tahu keberkesanannya bila di integrasikan dengan modul GRASS seperti the Man from U.N.C.L.E. boleh mengubahsuaikan pistol Walter P-38 menjadi senapang dilengkapi telescope. (JUPEM mungkin tidak akan suka membaca blog ini tetapi dilakukan demi ilmu) Pertama, peta kadaster JUPEM bagi negeri Perlis diaktifkan (pilihan ini berasaskan saiz fail) lalu di import ke GRASS. Kemudian, browser GRASS diguna untuk menojolkan topology error lalu dipilin 1 dari 3 output.  Secara random di zoomed-in lalu dipilih 1 garis. Di zoom-in lagi, nampaknya garis bukannya garis tetapi overlap atau gap. Disemak pula dengan peta kadaster asal, nampaknya garis tersebut adalah gap. Pada kawasan lain pula, terdapatnya rectangle. Di zoomed-in dan disemak dengan peta kadaster asal, didapati ianya tidak mempunyai nombor rujukan. Ini adalah gap atau mungkin ada yang lupa mengisikan atribut. Berasaskan pengalaman, kemungkinan besar, opsyen pertama adalah lebih tepat. Apabila di zoomed-out, banyak kes topology error ternyata dan terserah pada anda untuk membuat kesimpulan. Pokoknya, QGIS-GRASS boleh digunakan untuk menonjolkan topology error. Sama ada nak betulkan secara auto atau manual merupakan cerita lain. GRASS mempunyai ciri-ciri auto-cleaning tetapi soalnya adakah anda bersetuju dengan rules yang digunapakai? Ceritanya adalah sama bagi kes proprietari GIS. Sekiranya data cleaning bagi topology error dibuat secara manual jangan terkejut bilangannya boleh sampai ke ribu dan sekiranya saudara tak tahu keadaan sebenar, saya percaya amat sukar membetulkan topology error secara tepat dan melawat tapak tak bermakna garisan yang dilihat pada GIS akan lebih jelas. Buktikan saya salah.

Manual data verification through QGIS-GRASS

I have high respect for Malaysian Land and Survey Dept. (JUPEM) as custodian of Malaysian cadaster maps. Still, I have a toy to play with called QGIS and I wanted to see how it performs when integrated it with GRASS modules just like the Man from U.N.C.L.E. can modify his Walter P-38 pistol into a rifle with its telescopic extension. (JUPEM may not like to read this blog but what I did, I did for the sake of knowledge) Firstly, I activated a JUPEM cadaster map for the state of Perlis (choice was simply base on fail size) then imported it into GRASS. Next, I used the GRASS browser to expose for topology error then chose 1 of 3 outputs. I randomly zoomed-in and selected a line. Zoomed further-in, it was not a line, it was either an overlap or gap. Cross-checked against the original cadaster map, that line appeared to be a gap. Looking elsewhere, there was this rectangle. Zoomed-in and cross-checked with the original cadaster map, it had no reference number. It was either a gap or someone forgot to do his homework. From experience, the first assumption is closer to the truth. Zoomed-out, one can see many cases of topology error, I leave you to make your own conclusion.  The point of this exercise is that it is possible to identify topology errors with QGIS-GRASS. How one goes about cleaning it is another issue: auto or manual. GRASS has auto-cleaning capabilities but are you happy with the rules it applies? This can be said the same for proprietary GIS. If data cleaning of topology error is to be done manually do not be surprised it can run into thousands and unless you know the actual situation, I think it is impossible to accurately rectify the topology error and going to the ground does not mean you will see the lines you saw in GIS will be more clear. Prove me wrong.

Questionable polygon

Adjacent polygon has lot attributes

Snapping option issues

Snapping option issues

Since my department now uses all 3 GIS softwares, I decided to compare notes between ArcGIS, Mapinfo and QGIS in anticipation of queries. Today, I looked at snapping tolerance and found out that both ArcGIS and MapInfo snapping unit are only available in pixels whereas in QGIS, user can opt between pixels or mapunit have. (I am informed by blog member Saya Suka GIS below that this is not quite true for ArcGIS) Then again, the QGIS User Guide states that "the advantage of choosing pixels is that the snapping tolerance doesn't have to be changed after zoom operations". Next, I found out that the default snapping tolerance of ArcGIS and MapInfo is respectively 3 and 5 pixels whereas for QGIS, it is not set at 0.000000 either in pixel or mapunit. This means that the moment a ArcGIS and MapInfo layer is created, snapping of a digital feature is already possible and is comparatively more accurate in ArcGIS than in MapInfo by a ratio of 3:5. This does not exist in QGIS and if the user wants snapping, then customize a preferred tolerance. So what is the de facto set tolerance? Well, the more zeros there are, the more accurate the layer becomes where 0.001 has a higher tolerance than 0.1 but that level depends on the user's preference, for example, I was told that the Malaysian Land and Survey Dept. (JUPEM) for cartography purpose uses a snapping tolerance of 0.000001 pixels (you have to confirm it from the horse's mouth). This means that if a value-added layer was made from JUPEM's cadaster map, any amendment concerning topology ought to follow the snapping tolerance of the custodian to ensure that accuracy is maintained. No one is said another agency cannot use  a different snapping tolerance level but there are pros and cons to consider. My department has yet to establish a department snapping tolerance (policy) for all town planning agencies and I feel there should be and hope to address this issue in future. Thirdly, I also found out that a layer created with QGIS default tolerance of 0.000000 pixels when activated as a .tab file by MapInfo did not show pixel tolerance of the earlier GIS software but MapInfo's 5 pixel. This means another layer prepared at a tolerance level of say 3 pixel, if uploaded into MapInfo, unless adjusted, will stay 5 pixels. Looks like there is a need for standardization and coordination on this issue.

See you at MyGOSSCON 2012

Jumpa di MyGOSSCON 2012

MAMPU menjemput, kami respon lalu jabatan kami diterima untuk menyertai Pamiran MyGOSSCON 2012 di Hotel Marriott, Putrajaya pada 30-31.10.2012. Kami akan menerangkan apa yang telah kami buat selama ni sejak 2009 bagi Quantum GIS. Ini adalah kali pertama kami membuka booth di MyGOSSCON dan merupakan tempat sesuai untuk melayan pertanyaan QGIS sejauhmana dapat jawab tapi saya tak pasti saya boleh jawab semua kerana scope GIS amat luas dan dalam dan ilmu saya dalam bidang ini pada pandangan saya masih cetek. Jumpa disana.

See you at MyGOSSCON 2012

MAMPU offered, we responded and it was accepted that my department will open a booth at the Exhibition for MyGOSSCON 2012 at Hotel Marriott, Putrajaya this 30-31.10.2012. We will be telling visitors what we have been up to since 2009 insofar as Quantum GIS is concerned. This is our first time we open a booth at MyGOSSCON and will be a good place to answers QGIS queries whatever we can answer though I do not know if I can answer everything because the scope of GIS is very wide and deep and in my opinion, my knowldege of GIS is still inadedeqaute. See you there.

GIS information is a double edge sword

GIS Information is a double edge sword

People want GIS data as accurate as possible but when the information drawn from that is against what they hope to find, they will fault the agency that collected that data and term it inaccurate. We were babbling away on this subject when it was pointed out when information output-ed from some GIS data showed that there were some inadequacy in a certain area, it could help justify an agency to pump money there to alleviate that problem. However in a certain case, the politician for that region  went on and  formally quoted that no such issue arose within his constituency giving the impression that he has always been a Little Jack Horner. As I deal with GIS data, I am torn between producing accurate data which may backfire. To be or not to be, that is the question. Which is the price of truth? I grew up believing a simple philosophy taught by my mother who said "If you like say so, if you don't, say so" but now I've learnt that honesty may not be the best policy. Yes, as I grew older, I became wiser and learnt that people only want to hear what they want to hear because often the truth hurts. Unfortunately, GIS information acquired from GIS data is a double edge sword and can be hit back and the more accurate the GIS data, in the 'wrong' hands, the more deeper the cut can be. So what now: Collect data as accurately as possible or not?

Introduction to Quantum GIS talk at UITM?

Taklimat pengenalan kepada Quantum GIS di UiTM?

Saya perhatikan bilangan hits ke blog Introduction to Quantum GIS talk at UTM, Johor agak kerp dan ramai. Saya jangka mereka datang dari sumber UTM. Mungkin diluar sana juga ada pelajar UiTM  yang tettanya-tanya sama ada saya akan mengadakan takliamt seperti bergitu di UiTM. Pada tahun lalu, saya ada hunugi seorang pensyarah dan kawan yang tuju kami ke pentadbir Fakulti alam Binayang menayatakan mereka berancang untuk menggadakan satu pada tahun ini. Say tertanya-tanya pada waktu yang berbeza tapi tidak mendapat maklumbalas positif maka tidak bercadag untuk bertanya lagi, saya harap pelajar sedia maklum. Pelajar-pelajar UiTM pasi faham apa maksud saya dan megenang kembali dents. Kadangkala isunya soal nak ke tak nak.

Introduction to Quantum GIS talk at UITM?

I noticed the number of hits that came to the Introduction to Quantum GIS talk at UTM, Johor blog seems to be regular and high. I assume that they came from UTM source. There may also be UiTM students out there that may also be wondering whether I ever plan to hold a similar talk at UiTM. Well, last year I did contact  a senior lecturer friend who forwarded me to the Faculty of Built Environment's administrator who told me they were planning to hold one this year. I asked on different occasions the status but until now there has not been a positive feedback so I do not plan to ask again, UiTM students I am sure you understand, and to think I came from ITM. Sometimes it is merely a question of want or do not want.

Which is the best web mapping server for QGIS?

Apakah web mapping server terbaik untuk QGIS?

Soalan ini dah lama saya terfikir. Nasihat terbaik adalah syor OSGeo tapi itu juga ada beberapa opsyen. Pilihan saya adalah antara GeoServer, MapGuide Open Source (bukan MapGuide Enterprise) dan MapServer yang juga merupakan pilihan popular. MapServer mempunyai sejarah paling lama dan adalah rujukan utama seperti ArcGIS bagi desktop GIS. Perkara yang menarik dari fail pdf Jo Cook's Why web mapping?Why?How? menyatakan Goggle menggunakan GeoServer, MapServer dan Deegree, mungkin mereka tahu sesuatu. Saya tiada hasrat untuk membawa MapGuide Enterprise dalam perbincangan kerana ianya perisian berbayar. Saya juga tertanya mengenai pandangan perunding agar MapGuide Enterprise lebih baik dari MapGuide Open Source, mungkin kerana mereka tidak cerita sepenuh-penuhnya sebab:

1. Ada udang disebailk batu.
2. Sama ada klien akan betul-betul gunakan semua ciri MapGuide Enterprise.
3. Adakah MapGuide Open Source memadai untuk memenuhi keperluan klien?
4. Sama ada perunding  mahir secara teknikal untuk mengendalikan MapGuide Open Source? 

Saya tak pernah guna GeoServer, tapi mungkin tertaik dengan kaedah mesranya. Terdapat banyak post di Internet membincang perkara ini dan bersetuju ianya bergantung kepada  keperluan masing-masing. Dikatakan kalau nak kelajuan, pilihlah MapServer. Ada yang berkata pilihan programming akan mendorong ke pilihan mutktamad. Kalau OGC compliance adalah penting, pilih lah GeoServer. Saya masih mengkaji isu ini tapi buat masakini rasa terselamat dengan yang menurut garispanduan OGC. Beberapa pautan menarik adalah seperti berikut:

• Comparison of the different open source GIS servers from stackprinter
• Popular opinion from hiprank
• Completely Brand New to GIS - Help picking technology from the pros from stackexchange 
• MapGuide, Mapserver and GeoServer from osgeo
• MapGuide or MapServer for Enterprise from stackexchange
• Random Notes from Jason Birch
• Benchmarking 2011 by OSGeo
• gis,MapGuide or MapServer or any other open source GIS engine by mofeel

Which is the best web mapping server for QGIS?

This is a question that has been on my mind for some time. The best advice could be to take the recommendation of OSGeo but even so, there are a couple to use. My choice is between GeoServer, MapGuide Open Source (not MapGuide Enterprise) and MapServer which seems to be the popular options. MapServer has the longest history and I believe is like a reference standard as ArcGIS is to other desktop GIS. It is interesting to note from Jo Cook's Why web mapping?Why?How? presentation pdf file that Goggle uses GeoServer, MapServer and Deegree, maybe they know something better. I do not plan to bring MapGuide Enterprise into the scene because it is a paid software. I also question what  local consultants say that MapGuide Enterprise is better than MapGuide Open Source because I think they may be not telling the whole truth and nothing but the truth because:

1. There may be something to gain.
2. Will the client ever make use of most of the features from MapGuide Enterprise.
3. Is MapGuide Open Source more than adequate to meet one's requirement?
4. Does that consultant have the technical experience to handle MapGuide Open Source? 

While I have never used GeoServer, for some reason I do not know why, I have a soft spot for GeoServer, maybe I like their welcoming approach. Still there are many post in the Internet discussing this matter. I agree it boils down to user preference and requirement. They ('They' meaning the Internet ) say if it is speed and performance then MapServer has the edge. They say it's what programming are the you or your consultant is comfortable with so and that guides to your choice. Then they say if OGC compliance is preferred, well, GeoServer is the 'best'. I'm still researching on this but off hand I feel safer (and I believe, my top management) with those that comply with OGC, a non-profit organisation. Below are some interesting links:

• Comparison of the different open source GIS servers from stackprinter
• Popular opinion from hiprank
• Completely Brand New to GIS - Help picking technology from the pros from stackexchange 
• MapGuide, Mapserver and GeoServer from osgeo
• MapGuide or MapServer for Enterprise from stackexchange
• Random Notes from Jason Birch
• Benchmarking 2011 by OSGeo
• gis,MapGuide or MapServer or any other open source GIS engine by mofeel

How to convert from RSO to Cassini without errors?

People ask me whether QGIS can convert RSO to Cassini? If I tell them NO I can see expressions that signal 'Oh, most probably QGIS is inferior to proprietary GIS' If I tell them YES, they will ask 'How accurate is it?' so I avoid a direct answer and put them in a different perspective by asking them in the first place is it possible to convert RSO to Cassini or vice versa without errors? If the answer is YES, I say I too would like to learn how from them because simply I see both are of different projection. To exemplify, a RSO layer in Semenanjung Malaysia has Kertau, Pahang as its reference point so I tell them imagine shining a torchlight on a map of Semenanjung Malaysia to encompass the whole of it. The distance from the map to the bulb shall represent its projection scale. Now, if a Cassini map of Selangor is has its reference point somewhere in that state (don't know where) and another torchlight is made to shine encompassing that state, this distance from the map to the bulb will definitely be less than the earlier one for Semenanjung Malaysia. To a simple arithematician like me I see obviously will be error no matter whether done vice versa from Cassini to RSO but I am just informed by a senior cartographer friend that the error is 'very little and can be ignored' which I found this very interesting because I guess I think like a mathematician or accountant who want to close a balance sheet, every cent counts and on this matter, not like a cartographer. I was asked what is the difference between 1.0000000001 and 1.000000000009 or between 0.3333 and 0.333333? I would have answered it was relative to the user's requirement so who is to say which is more accurate because no matter what figure it is, it can be countered by someone who says mine is more accurate since it is more fine than yours like 'Anything-you-can-do-I-can-do-better' sort of thing which I have always encountered. Anyway, I would think a GIS software could  make up for error adjustment but the question is what rules were used and whether one agrees to that. Sometimes, people just because it comes from a particular GIS marque do not question it, do not care to think further and accept it as God's word. We can discuss this matter until the cows come home (if they do) but at this point in time, I have not finish with the subject coz I get to get some help, you must remember I am merely from the Arts stream and one who ended up muddling in GIS just knew sooner or later, in my field, I could not avoid it ... but until then keep surfing here, for update... if it ever gets done.

Finding information from data

Industrial land

Mukim

Merged layers

Output for a particular mukim with a particular industrial type

Finding information from data

Today, I just want to release some frustration: When I tell and ask people "We have lots of data on landuse but what sort of information are you looking for?" Those with big ego and this inclusive those from the top management will reply "Everything" which obviously means they  actually do not know what they want and are most probably too proud to admit it but how do I tell them that politely? I ask them "Please elaborate?" and they will tell this and that which I have to reply "That is data, not information. I am asking what type of information not what type of data" This answer baffles them because all the while they thought it was information. What continues sometimes end up in a light argument either because they are ignorant of GIS or because they are too stuck up and  don't want to admit it. This becomes a problem when that person is more superior. The other thing is that many people want certain information but do not know from what type of data layer is required to generate that particular information and neither does the GIS officer because the subject of that information is not his domain. Have you come across this incident? In GIS, specific type of data are often kept in separate layers and it is easy to query if it merely involves that type of data. However, sometimes there are instances when this is not so so I gave it a try to merged two different layers then made a query using the Query Builder. Yes, I got the answer I wanted but I must admit if one is not familiar in the use of SQL operators (which has nothing to do with QGIS but a tool that is used among all GIS softwares) it is going to be hard.

How to resolve Google Maps python error?

How to resolve Google Maps python error?

There are times when I want to activate Google Maps after having activated a few layers but this Python Error message comes up. I am no programmer so do not know what is happening? Deleting the vector files also does not remove the message. However closing QGIS and re-activating QGIS seems to solve that problem. It seems like Google Maps wants to be given first go then everything seems alright. Do not ask me why but so far, closing QGIS and switching it back again does the trick.

Recent Ubuntu QGIS installation issues

Home Ubuntu QGIS does not have right side column with tabs

 but office Ubuntu QGIS has right side column with tabs

Recent Ubuntu QGIS installation issues

This issue started when I found out that when I tried the New Print Composer with my home Ubuntu QGIS, the right side column which houses the setting tabs did not appear unlike the same version at my office Ubuntu QGIS. Weird! Fadzlan and me talked it over the phone and he recommended I re-install QGIS on the assumption that mine got corrupted along the way. No problem. I uninstalled my Lisboa version and using the Synaptic Package Manager, removed the QGIS files. What was left was Ver. 1.9.0 image files which I could not and do not know how to remove. What happened after this got me baffled as I found it difficult to re-install QGIS. I had to go a few rounds before I finally succeeded: 

• Round 1:
  
  I followed the steps recommended by our member, Gowin but QGIS did not install as it appeared there were issues with the Debian-nightly repository either because it was down or something else.
• Round 2:
  I tried to install QGIS using the Ubuntu Software Centre but that failed as shown below.
• Round 3:
  I tried to install QGIS using the Synaptic Package Manager, my regular way but even that too failed. It appeared that  the Debian-nightly repository did not work. 
• Round 4:
  I eventually managed to install QGIS using the Release version as I noticed the Master version required the Debian-nightly repository.

Steps

1. Under the Release section of the QGIS Download (home)page, copy "deb     http://qgis.org/debian precise main" and open file system/ext/apt/sources.list/Open with Software Sources then paste script into the input box of Software Sources/Other Software/Add (Of course, you have to click "Add");

2. The second script "deb-src http://qgis.org/debian precise main" got automatically entered so don't bother, just close Software Sources.

3. Next, Next, under the Release section of the QGIS Download (home)page, copy the first line of the repository public key "gpg --keyserver keyserver.ubuntu.com --recv 997D3880" then, under the Dash Home icon in the vertical menu bar, type "terminal' and click the Terminal icon to activate it then paste the script followed by Enter (key).

4. Repeat No. 4 but copy the second repository public key script "gpg --export --armor 997D3880 | sudo apt-key add -"

5. Go to the Update Manager and update for new patch files, if by chance they are.

6. Go to Synaptic Package Manager, type 'qgis' in the search box. You will find Ver 1.8.0 was downloaded. Select qgis and install by selecting Apply.

7. Under Dash home icon in the vertical menu bar, type "qgis" then pull the qgis icon to the vertical menu bar;

8. Click the QGIS icon and QGIS activates without any hiccup.

9. There are of course new plugins you may like to download later under Fetch Python Plugin

10. Finish.

At last, I got QGIS Lisboa working again. However, the New Print Composer issue still was there. At least, I know that the pervious steps I recommended earlier did not work but whether it is a temporary issue I do not know but this one does. Finally,  it was only at my office Ubuntu QGIS today did I find the solution to the New Print Composer which was merely to right-click the print composer menu bar (Rats, you never know until you try!) as shown on the last image below but had I known that earlier I would have never known recent Ubuntu QGIS installation issues :

Installation via Synaptic Package Manager

Yeah..got it at last!

Shortest path is so easy to use but...

Determine origin

Determine destination

See it run

And again when a road becomes one way in the opposite direction

Shortest path paling senang untuk guna tetapi...

Saya amat suka melihat modul Shortest path 'run' kerana hasilnya amat pantas, termasuk amat mudah untuk diguna. Pasti anda akan mengkagumkan sesiapa yang melihatnya beroperasi, tambah pula, bila melihat bagaimana arahtuju jalan mudah dimanipulasi dan dijadikan jalan sehala yang terbalik lalu run semula dan lihat bagaimana arahtuju tu berubah. Contohnya adalah seperti diatas, dengan syarat, setting sebelum ni telah dikonfigurasi. Masalahnya bukan mengenai modul tetapi pengumpulan data yang diperlu untuk menghasilkan output yang tepat... apa jadi pun, tetap anda boleh mengkagumkan sesiapa.

Shortest path is so easy to use but...

I really like to see the the Shortest path module runs because it does it so fast not to mention it is so easy to use. I guarantee you will impress anyone who sees it run and further impress them again when they see how you easily manipulate a road direction and re-set to be in the reserve direction then run the module and see how the direction changes. This is what I did in the example above but of course before that, I had to configure the setting. The problem with this exercise is not with the module but the collection of data required to produce accurate outputs...but impress anyone,  you will.

How to crop a map?

First make a frame to determine the actual border to crop

Next, always remember: The clip layer is the frame layer

Wala! The output as required. Now can go to sleep

Bagaimana hendak crop peta?

Tugas ini biasanya dibuat dengan GIS proprietari oleh staf sokongan mengikut permohonan klien. Kini mereka telah menggunapakai QGIS lalu bertanya sama ada dan bagaimana cropping boleh dilakukan dengan QGIS. Mengikut teori, saya pasti ianya boleh dibuat tapi saya mengakui tidak pernah menyediakan kerana tugas tersebut selalu di delagasi kepada mereka. Saya sebaliknya bertanya apakah teknik yang mereka guna lalu terus mencuba sama ada ianya dapat dibuat dengan QGIS. Pada peringat awal saya menggunakan modul Split feature tetapi terima kasih kepada ahli kita Saya Suka GIS seperti dibawah telah menasihat supaya menggunakan modul Clip dibawah Geoprocessing tool dan betul, ianya lebih mudah. Betul. Jelas ini menunjukkan bahawa walaupun mempunyai Sarjana dalam GIS tidak bermakna saya tahu semua mengenai GIS. Sekali lagi, banyak terima kasih.

How to crop a map?

This task is usually carried out using a proprietary GIS by my support staff upon request by a client. Now that some of them have adopted QGIS, they asked me if and how cropping could be it done using QGIS. In theory I knew it could but I admitted I never went about trying since that task was often  delegated to them. I was earlier using the Split feature module to crop but thanks to our member Saya Suka GIS below who guided me below to use the Clip module under Geoprocessing tool yes, it is much simplier. This proves that eventhough having a Masters in GIS does not mean I'm a Mr. Know-It-All in GIS. Many thanks, again.

Scale bar issues

Note the un-enable scale bar

Isu Scale bar

Saya kadangkala pening kepala dengan scale bar. Bergantung pada fail yang aktif, ada masa scale bar hilang, ada masa ianya dalam default degrees wal hal biasanya saya guna metres. Untuk re-set semula ke 'metre' biasanya dilihat bawah Project Properties tapi kini tak ada pulak. Kemana kah telah ianya pergi? Perlulah pengguna sedia maklum scale bar 'tersembunyi' dibawah View/Decoration tetapi apabila dipilih, tak akan aktif serentak. Pengguna perlu memilih 'enable scale bar'. Dah lupa kah? (Tak pa, ada kala saya juga begitu) Kedua, setelah scale bar aktif pada Map View, by default, ianya dalam mod degree so macam mana nak tukarkannya ke 'metre'. Walaupun Project Properties dah ghaib, pilih saja ikon bumi di belah bawah+kanan. Pilih tab General seterusnya 'metre' dan semua beres. Saya sengaja muat naik blog ni sebab saya juga kadangkala pelupa :-(

Scale bar issues

I sometimes get headaches with the scale bar. Depending on the file I activate, it sometimes goes missing, other times it is in default degrees when I usually use metres. I used to looked under Project Properties to re-set to metres but recently I could not find it. Now where has it gone? Well, for starters, the scale bar is actually 'hidden' under View/Decoration so one must get used to that. Having set that, selecting the scale bar does not immediately activate it. You have to select 'enable scale bar'. Caught you there didn't I? (Never mind, me too, sometimes) Secondly, even after the scale bar appears on the Map View, by default, it is in degree mode so how does one change that, say, 'metre'. It appears that even if Project Properties may have gone missing in action, just select the world icon at the bottom right hand corner of the screen. Then select the General tab and select 'metre' and everything is prefect if you want 'metre'. I am putting this up here simply because I too am forgetful :-(

Introduction to GIS Worksheets

Pengenalan kepada GIS worksheets

Hari ini, saya tertiba di laman ini. Ianya khas untuk guru dan pelajar GIS seperti saya dan merupakan maklumat yang amat baik lalu dikongsi bersama sini. 'About' menyatakan "This project was sponsored by the Chief Directorate: Spatial Planning & Information, Department of Land Affairs, Eastern Cape, South Africa (DLA)." Pengunting Utama dan Pengarang Utama lain tak lain adalah Tim Sutton dan Penolong Pengarang adalah Otto Dassau. Marcelle Sutton (Rasa-rasa bini kawan tu) adalah Pengurus Projek, maka, ni semua kerja satu keluarga. Worksheet-worksheet merangkumi:

1. Introduction to GIS
2. Vector Data
3. Attribute Data
4. Digitising Vector Data
5. Raster Data
6. Topology
7. Coordinate Reference System
8. Map Projection
9. Spatial Analysis: Vector Data
10. Spatial Analysis: Raster Data

• QGIS User Guide
• All worksheets in a single document
• Sample data used with tutorials

Elok dimuat turun saja dan cetak fail pdf dari All worksheets in a single documents bertajuk 'A Gentle Introduction to GIS' ( Saya pasti akan). Dokumen menyatakan "Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License". Ianya merangkumi Worksheet 1-10, sejumlah 101 muka tidak termasuk 13 muka dibelakang. Mantap dan terperinci, rujukan ini sukar usang kalau tanya saya dan amat sesuai bagi pengguna QGIS kerana ianya merujuk pada QGIS sebagai alat GIS. Setalah membaca 'A word from the editor', saya tabik mereka di Afrika Selatan.

Introduction to GIS worksheets

Today, I ended up at this site by accident. It is for teachers and learners in GIS like me and I believe I have struck gold and it is here for all to share. 'About' states that "This project was sponsored by the Chief Directorate: Spatial Planning & Information, Department of Land Affairs, Eastern Cape, South Africa (DLA)." The Editor and Chief Author is none other than Tim Sutton and Assistant Author is Otto Dassau. Marcelle Sutton (I assume it she relates to someone familiar) is Project Manager so it's all one big family. The worksheets cover:

1. Introduction to GIS
2. Vector Data
3. Attribute Data
4. Digitising Vector Data
5. Raster Data
6. Topology
7. Coordinate Reference System
8. Map Projection
9. Spatial Analysis: Vector Data
10. Spatial Analysis: Raster Data

• QGIS User Guide
• All worksheets in a single document
• Sample data used with tutorials

Do yourself a favour, just download and print the pdf file from All worksheets in a single documents called 'A Gentle Introduction to GIS' ( I definitely will). The document states that "Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License". It covers Worksheet 1-10, a total of 101 pages less the extras 13 pages at the back. Real solid and detail, a real reference timeless standard if you ask me best suited for QGIS users because it makes reference to QGIS as the GIS tool. I take my songkok (hat) off to you guys at South Africa after reading 'A word from the editor'.

Fooling around with hills

Using polygons to make contours

Transforming polygons into lines

Extracting nodes from lines

Trying out a Delaunay  triangulation

Godek-godek sekitar bukit

Sudah amat lama sejak saya menjalankan analisis kecerunan yang dibuat semasa kursus sarjana, oleh tu, minta ampun sekiranya lupa teknik berkaitan, dah tua. Akan tetapi, bergantung kepada apa yang   masih diingati, saya aktifkan Google Physical dan cuba mewujudkan selar menggunakan kaedah polygon kerana tak perlu memikir macam mana nak sambungkan titik permulaan dan titik hujung. Saya  mula cari jalan mudah dan jumpanya bawah Geometry tools dimana boleh ditransformasikan  polygon ke garis, lalu mencuba dan berjaya! Attribute table juga cemas ditransformasi. Dah mula berani, terus saya mencuba wujudkan node dari garisan (contour) menggunapakai Geometry tools dan berjaya sekali lagi. Yahoo! Saya teruskan dan cuba menjalankan Delaunay triangulation dan berjaya menghasilkan output berkaitan. Akhirnya, saya nak nak terus interpolate node tetapi dah lupa macam mana nak buat. Cis! Pasti saya ni dah tua tapi kini sedang membaca cara-nak-buat disini.

Fooling around with hills

It has been a long, long time since I toyed around with slope analysis when I did my Masters of Science course so excuse me if I forgot a lot about the techniques required, I'm getting long in the tooth. But relying on what I remembered I activated Google Physical and tried to create contour lines using the polygon way because it seemed simple than having to think how to tie the end to the starting point. I looked at ways on how to cheat then found out under Geometry tools, it is possible to transform polygons to lines so I gave it a try and yes! It worked! Even the attribute table was correctly transformed. Getting braver, I tried to extract nodes from the (contour) lines using the Geometry tools and it worked. Yahoo! Just for the heck of it, I gave the Delaunay triangulation a try, it successfully produced the appropriate output. Lastly, I wanted to proceed to interpolate the nodes but forgot how to go about it. Rats! No doubt about it, I'm getting old but I'm reading how-to here. 

Cleaning data topology manually

Membaiki topologi data secara manual

Pada latihan QGIS barukini, saya telah melatih cara pengguna QGIS boleh mengeksploitasi modul-modul v.clean yang terdapat pada GRASS GIS. Dari perbincangan yang lanjut, ianya mendedahkan saya kepada kelemahan membaiki topologi data secara automatik oleh GRASS GIS lalu saya melayar Internet dan mendapati Arcinfo juga boleh membaiki topologi data secara automatik seperti di contohi   'Eliminate'. Teknik auto-cleaning oleh Arcinfo dan GRASS GIS sedikit tidak memuaskan kerana adanya kala dimana perisian tidak dapat membaiki kesilapan berasaskan rules yang ianya pegang dan apa yang ternyta di bumi tidak sebegitu yang disangka oleh perisian. Teringin saya menentukan bagaimana QGIS dapat membaiki topologi data secara manual. Hari ini, apa saya mendapati sedia ada merupakan modul 'Check geometry validity' dibawah Vector/Geometry tools, maka, mencubanya. Nampaknya output spatial tidak dapat terpapar seterusnya tetapi perlu dihasilkan dari teks yang ditransformasi dengan bantuan Delimited text layer. Akhirnya, saya berjaya menghasilkan lapisan spatial yang menjelaskan taburan kesilapan mengikut vertex bagi beberapa poligon. Ini adalah baik kerana pengguna boleh terus membaiki vertex tertentu yang memerlukan pindaan.

Cleaning data topology manually

During the recent QGIS training exercise I taught the QGIS user could exploit the many cleaning v.clean modules under GRASS GIS. During discussions, it exposed me to the limitations of auto-cleaning data topology offered by GRASS GIS. I surfed the Internet and found Arcinfo could also auto-clean data topology exemplified by 'Eliminate'. However, the auto-cleaning technique used by both Arcinfo and GRASS GIS left me a bit unsatisfied because there are situations where the software is not able to correctly rectify errors based on rules it held and what is on the ground is not how the software thinks it should be. This spun me to find a way to find out how to get QGIS to clean data topology manually. Today, what I saw currently available is the 'Check geometry validity' tool under Vector/Geometry tools and decided to give it a try. It seems the spatial output could not be immediately shown but had to be transformed from text obtained with the help of the Delimited text layer module. I eventually got a spatial layer showing the distribution of errors by the vertex of many polygons. This is good because the user can now proceed to rectify the specific vertex that needed repair.

* National Landuse Information Division gets QGIS training

Bahagian Maklumat Gunatanah Negara mendapat latihan QGIS

Semalam, setelah memberi lebih dari 10 sesi latihan QGIS  kepada agensi-agensi luar, bahagian sendiri baru diberi latihan QGIS. Terdapatnya beberapa pegawai baru mengikutinya tetapi amnya semua mahir dalam penggunaan perisian proprietari GIS, maka, tidak perlu saya mengajar dengan pelahan. Walau bagaimanapunm nampaknya banyak perbandingan dibuat antara QGIS dan proprietari GIS. Ini memberi gambaran bahawa terdapat kesukaran penyesuaian mindset bagi beberapa peserta. Hari ini, saya perlu menegaskan bahawa walaupun semua buah-buahan terletak dibawah kepala BUAH-BUAHAN, perbezaan besar terdapat antara epel dan oren dimana tidak wajar kita membuat perbandingan antara kedua-dua itu tetapi lebih wajar dibuat antara produk dari lain-lain wilayah seperti oren California dan Itali atau epel Perancis dan British. Dalam kata lain, ArcGIS vs MapInfo atau QGIS vs. QGIS OK tapi antara ArcGI/Mapinfo vs. QGIS tak OK. Apa terjadi pun, sesi latihan QGIS ini lebih menumpu kepada verifikasi data dan penapisan data mengikut keperluan klien kerana  merupakan jenis-jenis kerja yang selalu dilakukan oleh bahagian saya.

National Landuse Information Division gets QGIS training

Yesterday, after giving more than 10 sessions on QGIS training to other agencies, eventually my own division gets trained in QGIS. There were some new officers but most of them already were familiar in the use of a proprietary GIS so I did not really need to go slow on them. There appeared much comparision between QGIS and proprietary GIS which gives me the impression that adjustment of mindset can be difficult for some. Today, I will have to stress that just because all fruits come under the umbrella of FRUITS, there is a mark difference between apples and orange where one does not make comparison between the two but maybe between regional products say between the Californian and Italian orange or the France and British apple. In other words, ArcGIS vs MapInfo or QGIS vs. QGIS is OK but between ArcGI/Mapinfo vs. QGIS is not OK. Having said that, the QGIS training session was more shewed to data verification and customization/filter of maps according to the needs of a client which much type of work is carried out under my division.

Peserta

Noraza Yusoff

Pendapat iklas, kena teruskan latihan supaya lebih memahai. Mudah dan senang difahami lagi.

Farahanie Jaafar

Memerlukan banyak latihan untuk memantapkan lagi pengetahuan mengenai Quantum GIS.

Habibah Abdul Aziz

Kelas perlu diterangkan fungsi ikon atau button ayng ada secara lebih detail supaya kela s lebih faham dengan jelas tidak terlalu megikut 'step'. Jika terlalu terpengaruh dengan 'step' pengajar, selepas kelas, student akan mudah lupa sebab tak faham tapi follow saja.

Siti Zawani

Mudah dipelajri dan mesra. Note perlu diberi seblum kelas supaya lebih jelas bagi beginner. Perlu banyak latihan diberi kepada pelajar.

Suhaimi Hasan

Satu perisian yang baru, mempunyai tools yang lengkap sebagaimana lain-lain perisian GIS. Bagaimana pun pendedahan dan latihan yang berterusan supaya dapat dipraktikan dan digunakan secara lebih meluas. Memerlukan kecekapan individ dalam memahami tatacara penggunaan dengan pantas. Perlu masa dan beri peluang kepada kakitangan.

Nora Haron

Perisian yangs etanding dengan perisian GIS yang lain walaupun ia secara open source. Perlu mendalami lagi dan membauta tugasan menggunakan terus software ini.

Mohd Rizal Shamsuddin

QGIS merupakan perisian yang mudah dipelajari. Pelru digunapakai setiap hari. Perlu ditambahkan tempoh masa yang panjang bagi memahirkan pengetahuan QGIS.

Mohd. Soffi Othman

QGIS merupakan perisian yang mudah dan mesra pengguna tetapi memerluan kemahiran meningat kerana banyak langkah yang perlu diketahui. QGIS memerlukan talian Internet yang mantap untuk memudahkan penggunaannya. Oleh itu, Internet perlukan ditambahbaik untuk lebih mudah menggunakan perisian QGIS ini. Latihaan perlu diteruskan dari masa ke sema untuk memantapakan lagi pengetahuan.

Azizul Nizam

QGIS secaraasasnya boleh membantu dalam penyediaan peta rancnagan pemajuan namun banyak perlu dipelajar oleh pengguna mengenai cara penggunaan dan mengetahui apa yang boleh dibuat mengenai QGIS. Penggunaan berterusan dan latihan yang lebih untuk mengetahui apa teknik baru dan sistem baru yang boleh digunakan. Saya berharap satu hari nanti QGIS dapat menangani atau lebih baik daripada software- software yang lain.

Mohamad Zamri

Boleh membantu dalam menyelesaikan tugas tugas harian yang melibatkan GIS. Walau pun begitu ianya masih memerlukan juga perisia-perisian GIS yang lain  bagi mantap dan lebih user-friendly didalam membuat nalaisis dan membaiki topologi file yang sedia ada.

Mislah Badli

Satu perisian yang mesra tapi memerlukan kecekapan indivu untuk penggunaan pantas. talian interent yang dapt menampung perisian tersebut. Perlu berterusan dalam suaha untuk pendedahan dan mendalami satu perisian yang baru. banyakan latihan.

MAMPU replies

Maklumbalas MAMPU

MAMPU, dibawah Jabatan Perdana Menteri telah memberi maklumbalas mengenai penggunaan QGIS oleh jabatan kami pada 17.8.2012 dan boleh dibaca dari pdf ini. 

 Ha-ha-ha! I tahu apa yang saya buat selama ni adalah betul. Kalau betul, betul lah!

MAMPU replies

MAMPU, the Malaysian Administrative Modernization and Management Planning Unit  under the Prime Minister Department, responsible for ‘modernizing and reformizing’ the public sector in the areas of administrative reforms replied on 17.8.2012 to my departmental query on the use of Quantum GIS. MAMPU stated our decision to use QGIS and reduce reliance on proprietary software is in line with MAMPU's Public Sector Open Source Software Program. MAMPU stated this will improve public service delivery to the citizen and can achieve the following objectives :

• reduces ownership cost and assist in the reducing the cost of acquisition;
• free from vendor lock-in situations;
• increases software and data security;
• free the agency when developing and implementing a system;
• increase system interoperability at the agency and between agencies.

MAMPU stated the use of QGIS also reduces the cost of implementing ICT and increases technical competency of government officers. This leads to the growth of the user community and contributes towards a knowledge society. MAMPU confirms that QGIS is a mature, stable, free from vendor lock-in and cannot be commercialized by any third party because it was licensed under the GNU General Public License version 2.0. MAMPU acknowledges the QGIS global community has the support of the non-profit organisation known as 'OSGeo' or Open SoucreGeospatial Foundation but notes the QGIS community in Malaysia has still not matured to give technical support and software development. Thus, MAMPU recommends agencies in Malaysia desirious of using QGIS be self reliant by improving their know-how and ability when implementing GIS as this in in line with the Malaysian Open Source Public Sector Master Plan Phase III -  Self Reliance.

Ha-ha-ha! I knew all the while, I was on the right track all the time. When I'm right, I'm right!