INGENIEUR
DATA
The spatial and temporal data acquired for this research were divided into three categories which are cadastral data , satellite data and aerial images .
( i ) Cadastral Data A cadastral map is a map that shows the boundaries and ownership of land parcels . These cadastral maps can be acquired through a website ( https :// ebiz . jupem . gov . my /) under Jabatan Ukur Dan Pemetaan Malaysia ( JUPEM ). In order to place data requests , it is necessary to know the state code , district code and the lot numbers of the area of study . For this study area , the codes and lot numbers of the area of interest is as shown in Table 1 . The cadastral layer acquired comes in a digital form (* shp ) and is projected in Cassini- Soldner projection .
Description
Negeri ( State ) – Perak
Daerah ( District ) – Selama
Mukim ( Sub-District ) – Selama
Codes 08
09
03
Lot Number 9862 , 9863 , 6042-6067 , 4944 & 46696
Table 1 : Codes used to acquire the cadastral lot from JUPEM website .
( ii ) Satellite Images The data used to create the satellite images for this specific research were obtained from the Landsat TM & OLI / TIRS data , Shuttle Radar Topography Mission ( SRTM ) data , SPOT-5 image and satellite images acquired from Google Earth . The Landsat 4 and 5 TM images with 30-metre resolution dated from February 28 , 1980 to July 10 , 2010 and a set of Landsat 8 OLI / TIRS images with 30-metre resolution dated from April 19 , 2015 to July 5 , 2020 were used for the analysis . The bands used for both type of Landsat data were the red band and the near infrared ( NIR ) band ( for NDVI analysis ) and thermal bands ( for LST analysis ). It is important to keep in mind that different Landsat satellite images have different band designation .
For example , Landsat 8 OLI / TIR data , the red band ( 0.63 – 0.69mm ), NIR band ( 0.76 – 0.90mm ) and the thermal band ( 10.6-11.19mm and 11.50-12.51mm ) are designated as band numbers four , five , ten and 11 respectively while Landsat 4 and 5 TM , the red band is designated for band number three , the NIR band is for band number four and the thermal band is for band number six . The projection used for these images are the Universal Traverse Mercator ( UTM ) Zone 47 . Currently the best available SRTM data comes at 30-metre resolution and can be digitised with remote sensing or GIS software . This research uses the SRTM GeoTIFF data from USGS Earth Explorer dated September 23 , 2014 . The data was projected in Mercator Projection which is commonly used for maps of the world . The SPOT- 5 images were acquired from Malaysian Space Agency ( MYSA ) official website ( http :// www . mysa . gov . my / portal / index . php ). The images used were dated November 30 , 2012 and have four bands altogether . The images had a resolution of 10 metres for all bands except for Band four where its resolution was 20 metres . The sub-pixel analysis of Band three , the Near Infrared Band ( 0.78-0.89 μm ), was used to analyse and detect the river course since it has the highest potential to map out the waterbodies compared with other bands ( Ismail & Usali , 2010 ) .
PRE-PROCESSING
This procedure is to correct the image from errors and to project the image in the required projection . Generally , it is grouped as geometric and radiometric corrections and for this project , both these corrections were applied .
( i ) Geometric Correction Geometric correction is used for correcting the geometric distortion due to the sensors and for the conversion of the projection . The Landsat images from the year 1980-2020 , and SPOT-5 data were rectified so that the images were in the same projection which is the UTM Zone 47 with datum of WGS84 . Then , all the data used was clipped to the area of interest based on the cadastral shapefile . As for SPOT-5 image , there were a few distortions to the image , so orthorectification was done to correct the image .
52 VOL 84 OCTOBER-DECEMBER 2020