University of the West of England, Bristol BSc Geography and Environmental Management

GIS AND REMOTE SENSING APPLICATIONS PORTFOLIO

(UBGMSU-30-3)

Tony Gregory

Reflective Diary: Description:

The structure of this report is based on Gibbs’ reflective cycle (1988). It encourages reflexive and

reflective thinking about the different stages of an activity or experience (Gibbs, 1988).

For the GIS Remote sensing applications module this year, a new program was introduced. The aim

was to develop an understanding and operate Erdas Imagine to complete two tasks. The first task

was a land cover change analysis of Rondonia, Brazil. An unsupervised classification was performed

for the dates 1999-2013 to identify land cover change, and a Normalised difference vegetation index

to recognise change in vegetation quality.

The second task was a Burnt area analysis on UKhahlamba; an area in the South African

Drakensburg. ERDAS imagine was used to quantify the extent of burnt area between April – October

2013, and the Normalised Burn Ratio across the same dates. All maps created were transferred to

Arc map to create aesthetically pleasing files.

Feelings, evaluation and actions

Initially I felt worried and anxious after discovering that we would be using a new computer

programme, having previously become very familiar and with Arc GIS. My initial feelings were

amplified once I began following the videos provided by Michael. The structure was simplistic which

allowed me to follow the tasks without an issue, but the unfamiliarity of the programme made me

feel like I had no understanding of what I was trying to achieve, and so felt I was following each task

without really learning along the way. This became evident when performing an unsupervised

classification for the first time. I created slightly inaccurate landcover maps with some areas being

represented as afforestation when it was obvious they were not. The error occurred when assigning

the spectral classes and performing the matrix union; I experienced this on both the landcover

analysis and the burn change analysis, causing me to have to perform these tasks several times

which created stress and I became disheartened. I eventually got the hang of them and produced

representable maps. I felt this was an achievement and would be able to perform the task a lot more

efficiently next time round. If I was in a position to do them again I would do one of two things. I

would produce computerised matrix unions rather than a hand drawn one so as to avoid

misunderstanding when I referred back to it later on, or if possible I would perform a supervised

classification (Richards, 1993); this would increase the accuracy of my work and reduce confusion.

I felt very self-assured when completing the NDVI and NBR elements of the portfolio. They went a lot

more smoothly for me than the other tasks; I feel this was because the length of each task and the

structure was slightly less complex with fewer areas to trip up on. I would not change my approach if

I was to tackle these tasks again.

At times I felt I was getting the hang of the programme, especially after completing the Rondonia

task, which grew my confidence; however with confidence came a degree of arrogance which

caused me to make mistakes at the recode stage on the UKhahlamba task. This resulted in

substantial setbacks in my progress, and on two occasions I had to re start the entire change

analysis. I felt I would never grasp the Erdas imagine program at this point, but I persevered with it

to create maps I was pleased with. In hindsight I would write down key notes throughout the task so

as to not confuse myself and to avoid making simple errors.

I found some aspects of the programme such as the swipe tool very useful and easy to use, but

differentiating between landforms due to my lack of knowledge meant some classes were

misrepresented. I became impatient with this part of the task and rushed certain decisions over

assigning classes. I would take longer over decisions and not let impatience get the better of me in

the future.

I felt relieved after each recode as it signified the end of using Erdas imagine and the start of Arc

GIS. My previous work with this programme made me feel at ease and a lot more comfortable purely

because of the familiarity I associate with it. The result of this was final maps that I felt exceptionally

proud of.

Conclusion

Having learned that the new program is not as daunting to use as I originally feared and now I feel

that I could carry out similar assessments with considerably less trouble. I have significantly

improved my understanding of the ERDAS system which makes me feel very satisfied with my

development as an undergraduate. This understanding will be essential to me for future prospects if

I decide to take GIS further as a potential carrier choice. As a next step I need to take forward what I

have learnt so far and employ that knowledge to the rest of the module.

References:

Gibbs G (1988) Learning by Doing: A guide to teaching and learning methods. Further Education

Unit. Oxford Polytechnic: Oxford.

Richards, J. A., (1993). Remote sensing digital image analysis: an introduction (second edition)