## Introduction

DEM: Digital Elevation Model; land surface elevation
Usage/purpose: slope, infiltration (qualitative; higher infil. where GWT is lower from surface), landslide potential, ...
Sources: ... // may skip

TIN: Triangulated Irregular Network
Three corners hold three elevation
Easy to interpolate

## Tutorial

### Data Import

1. Search "excel to table" or ArcToolbox > Conversion Tools > Excel > Excel to Table
1. Display XY Data from the generated layer
1. Specify: X -> East; Y -> North; Z -> Height
1. Coordinate not required now

### DEM (3D)

1. 3D Analyst Tools > Raster Interpolation > Topo to Raster
1. Choose "Field" = "Height", "Type" = "PointElevation"

### DEM (2D)

1. Spatial Analyst Tools > Interpolation > Topo to Raster

### Contour

1. Spatial Analysis Tools > Surface > Contour
2. Specify interval `3`

### Contour to TIN

1. 3D Analyst Tools > Data Management > TIN > Create TIN
1. Specify "Input Feature Class" = Contour_..., Height = Contour

DEM to TIN -> DEM > Contour > TIN

### TIN to Contour

1. 3D Analyst Tools > Conversion > From TIN > TIN to Raster

May choose different color ramp to better represent