Chapter 2 Reading Topographic Maps and Making Calculations

The Cartographic Journal, 2018

Advanced GIS, 2010

Student Assignment Nr. 5 'Topographic Modelling' for the for the module ’Geographical Information Systems: Advanced Course (GISA02)’. Several exercises on ArcGIS for topographic modelling are performed. Slopes for the 3D model were calculated using ArcGIS Spatial Analyst module, which is based on mathematic calculations of the maximum rate of change between cell and its neighbours. Each cell has its place in the matrix of the cells, and is surrounded by the neighbouring cells. To calculate the slope ArcGIS was used to computes the difference between the values of the cells (8 neighbouring cells). Estimation of aspect was donefor searching of slope direction (north-facing or south-facing slopes on a mountain). To estimate aspect, ArcGIS was used Surface Analyst, which includes Map Algebra, i.e. estimation of the maximum rate of change in value from each cell to its neighbors in the cell values matrix. Results include computed and visualized aspect criteria (only north facing, from 2700 W to 900E) fill 462424 cells. Slope criteria (flat ground up to 50) fill 259643 cells. Reclassification method was used to create one raster filling both criteria was following: Surface Analyst was used to create Slopes and Aspect rasters from the initial DEM raster. The calculated area of the potential plant growing sites based on the Slope and Aspect criteria is 863095500 m2, which is 106555 cells times 8100 (cell resolution). To receive this result I multiplied both rasters of Slope and Aspect conditions using ArcGIS Raster Calculator and received new raster filling both criteria. The overlay operator is Spatial Analyst – Raster Calculation – Multiplication (*).

Politeknik Sultan Abdul Halim Mu'adzam Shah, 2022

Teaching document for student to study.

1990

2001

The shape of the Earth's surface, its topography, is a fundamental dimension of the environment, shaping or mediating many other environmental flows or functions. But there is a major divergence in the way that topography is conceptualized in different domains. Topographic cartographers, information scientists, geomorphologists and environmental modelers typically conceptualize topographic variability as a continuous field of elevations or as some discrete approximation to such a field. Pilots, explorers, anthropologists, ecologists, hikers, and archeologists, on the other hand, typically conceptualize this same variability in terms of hills and valleys, mountains and plains, barrows and trenches, that is, as (special sorts of) objects, with locations, shapes, and often names of their own. In this chapter, we sketch an approach to bridging this fundamental gap in geographic information infrastructure.

Cartography (from Greek χάρτης khartēs, “map”; and γράφειν graphein, “write”) is the art and science of representing geographic data by geographical means. Maps are the main products of cartographic work and are graphic representations of features of an area of the Earth or of any other celestial body drawn to scale. Regardless of the map type or the mapping technique applied (Chapter 3.2), every map has a coordinate system, a projection, a scale and includes specific map elements. These attributes usually depend on the size and shape of the mapped geographical area and the graphical design of the map representation that needs to be informative and understandable for the map-user (Chapters 5.4 and 6.4). Geographic Information Systems (GIS) are powerful tools for data Input, Management, Analysis and Presentation (IMAP principle) providing multiple possibilities for a better understanding of the structures and patterns of human and natural activities and phenomena (Chapter 3.4). Nevertheless, much of its easy-to-apply default-functionality can be misleading for an inexperienced map-maker. In the present chapter, we discuss the main characteristics of maps such as coordinate system, geodetic datum, projection, scale and map elements; how to choose them accordingly and what their role is for proper use of a map. The use of GIS has significantly simplified mapping and provides a good environment for the visualisation of Ecosystem Services (ES).