08/05/2013

How to prepare GIS plans without a proper map?

Untick  that 'On-the-fly' projection
Import Google Hybrid as base map
Create a location map using polygon feature
Identify the study area limit by making colour fill invisible
Calculate site acerage using field calculator
Add and label road access using line feature
Add and label building types using point feature
Add supporting data e.g. firebreak
Add and distinguish tree types (Need transformed GPS data, here)
Add and distinguish soil class using polygon feature
Count by 'Points in a Polygon' module if this interest you
Bagaimanakah untuk menyediakan pelan GIS plans tanpa peta yang sewajar?

Saya masih ingat semasa mengikut ijazah, betapa sukarnya untuk memperolehi data digital. Kini data digitla amat mudah diperolehi dan dengan QGIS, perkara ini lebih mudah kerana anda boleh menyediakannya sendri. Oleh itu, artikel ini adalah khas untuk pelajar GIS yang mengalamai apa yang saya melalui dulu. Pertama, untick 'On-the-Fly' projection kerana nanti leceh apabila nak betulkan projection semua lapisan GIS bersama Google Maps. pastikan scale bar aktif untuk mengar GIS supaya syn lapisan GIS kepada scale bar. Kesemua lapisan saya disini telah diproject mengikut Google Maps kalau tidak nak cari pasal. Penentuan keluasan kawasan juga mudah akan tetapi saya mengakui masih tak tahu bagaimana nak kawal decimal points tetapi sekurang-kurang ianya adalah tepat. Kerja mengklasifikasi pelbagai jenis fitur menyeronokkan kerana ianya akan menonjolkan maklumat pada data spatial. Sudah tentu ketepatan fitur akan bergantung pada kegunaan alat GPS dan seperti telah saya buktikan dulu, data GPS mudah diterjemahkan secara spatial dengan QGIS. Amnya apa jenis maklumat yang diingini bergantun kepada apa data yang pengguna simpan dalam pangkalan data. Senarai ini tiada penghujungnya. Semua ni saya siapkan dalam tempoh kurang dari sejam tak susah asalkan ada sifu yang pandai [...seperti saya :-) ]

How to prepare GIS plans without a proper map?

I can remember when I taking my Masters, how difficult it was then to acquire digital data. Now digital data is easy to come by and with QGIS around, things are getting even more simple, you can even do it on your own. Thus, this article is especially for GIS students who face the same situation as I once went through. Firstly, I would start off by unticking the 'On-the-Fly' projection because it gets messy when I want all my GIS layers to align with Google Maps. Make sure the scale bar is activated to teach the GIS to syn the GIS layers to the scale. All my new layers would be map projected to Google Maps or else I am asking for trouble. Plot acerage is simple though I admit I still haven't learn how to limit the decimal points but at least it's precise. Classifying the various types of features is fun because it creates impressive looking spatial data. Of course, pin-point accuracy of features requires the aid of a GPS but as I have shown before GPS data can easily be spatially presented with QGIS. All-in all, it really boils down to what information the user wants to show and store in the database. The list is endless. By the way, I did all the above exercise and uploaded them here in less than 1 hour so it's really not difficult but you need a good teacher [...like me :-) ]

2 comments:

  1. salam En. Abas
    kenapa gambar tak dapat dilihat?
    saya baru nak buat sebagai rujukan.
    -pelajar Gis-

    ReplyDelete