Friday, 10 May 2019

Add Surface Information (Z-value) to Point or Polyline from DEM

This is a good explanation on how to add surface information, which is z-value to point or polyline from digital elevation model. 

This is all simply done using ArcGIS, through the 3D Analyst tool "Add Surface Information".


Credit to GIS Coordinated

Alternative video (Click Here)

Saturday, 4 May 2019

Tools for bathymetry

(Alternative Video)

This youtube video is a good tutorial on how to set up tools for bathymetry. The tools that we need is:
  1. GPS
  2. Controller
  3. Transducer (sonar)
  4. Single beam echo sounder (connect to transducer & controller (Bluetooth)
  5. Boat!
I wish to have all the tools for my research. Wish me luck!

Adjust (such as Resize & Move) Raster Image and Shapefile in ArcGIS (Georeferencing)

This is a good tutorial on youtube, on how to georeferencing raster image and shapefile as follows. Georeferencing is the process you fix the referencing or coordinate of the raster. In simple word, georeferencing can be explained as the process you resize or move the raster/shapefile. At the end of the process, you will get the correct coordinate.

Georeferencing for both raster and shapefile have their own steps. The steps as follows:

1. Georeferencing the raster image

Tools that been used in this example are:
- Georeferencing (Tips: Click control points and right click on frame to insert the coordinate)
- Effect (to help with the process - reduce the brightness of the raster)

Original video (Click Here)

or



Download the video (Click Here)

2. Georeferencing the shapefile

Tool that been used:
- Spatial adjustment (similar way to used like Georeferencing as above)

Original video (Click Here)

Download the video (Click Here)

Note: All videos that been used in this tutorial are from Youtube. The writer does not take any credit or responsible (copyright issue) from those videos. 

Wednesday, 1 May 2019

Box Plot Template using Excel

Box plot template using Excel. Download here

Monday, 29 April 2019

Watershed Delineation and River Formation using Digital Elevation Model (DEM)

Here a good example and tutorial from youtube for watershed delineation and river formation using digital elevation model (DEM).

The steps as follows:

Watershed delineation
1. Spatial analysis tools
       -> hydrology
            -> fill
            -> flow direction
            -> flow accumulative
            -> basin (using input from flow direction)
2. Conversion tools
      -> from raster
            -> raster to polygon (using input from STEP1-basin)
Clip the selected watershed
3. Geoprocessing
      -> Clip (select watershed that want to clip)
River formation
4. Spatial analysis tools
      -> map algebra
            -> raster calculator
                  -> flow accumulative > 500 (value is example)
                  -> flow accumulative > 1000 (value is example)
5. Conversion tools
      -> from raster
            -> raster to polyline (using input from STEP 4-flow accumulative>1000)
                  -> Clip
Clip the DEM raster
6. Data management tools
      -> raster
            -> raster processing
                  -> clip (input (raster), output extend (basin, STEP3), click used input feature for clipping                         geometry)

Tuesday, 23 April 2019

2d flood modeling in hec-ras using precipitation as sole input

A good tutorial on Yotube by using precipitation as sole input to HEC-RAS for 2d flood modelling.


Monday, 25 February 2019

Aktiviti Pemetaan Menggunakan Drone di Sekitar Kampus Utama UniMAP

Pada 23hb Feb 2019, salah seorang pelajar Projek Tahun Akhir (PTA) menjalankan aktiviti PTA beliau, iaitu membuat pemetaan menggunakan drone bagi mengatasi masalah banjir kilat yang pernah terjadi di kampus utama UniMAP. Walaupun masalah banjir ini tidak serius dan merupakan kes terpencil, namun ianya menjadi salah satu kajian yang menarik, bagi melihat perubahan hujan dan menganggar kadar aliran air di sekitar kawasan kampus.

Dalam aktiviti drone, beberapa gambar yang diambil menggunakan drone akan dianalysis oleh software bagi mendapatkan kontour (contour) sebenar bagi kawasan kampus. Kemudian, contour tersebut akan dianalis dan dibahagikan kebeberapa kawasan tadahan hujan. Ciri-ciri kawasan tadahan serta beberapa parameter akan dimodelkan dalam HEC-HMS atau HEC-RAS bagi mendapatkan kesan hujan daripada beberapa senario hujan yang diberi.

Barikut antara aktiviti yang dijalankan oleh pelajar PTA berkenaan:



UPDATE: 4 MAY 2019: The river paths that been projected using drone image by some software.