Visualizing Trig Functions

Trigonometric functions are often used to model repeating patterns that occur in real life.

To successfully work with trig ratios, a useful starting point is visualizing the relationships. The links below provide info on visualizing trig ratios

• Best Sine, Cosine,and Tangent Visualization Tool
• Introduction to Trigonometry 
• Book Chapter providing details of trig functions 
• Learn to apply trig ratios to solve practical Trigonometry
• Graphing Trig Functions
• Overview of the Overview of the Trigonometric Math toolset in ArcGIS 

Sampling

Knowing how to perform spatial sampling is a critical skill for GIS analysts. Click on the links below for info on how to perform spatial sampling using ArcGIS and R.

1. Sampling Design Tool (ArcGIS 10.0)

2.Spatial Sampling with R module, sp

3. Using R for spatial sampling of raster layers 

4. Sample point locations within a spatial region

5. GRTS Spatial Sampling

6. The spsurvey package is great for spatial sampling.  It can sample points, lines, or polygons using either simple random sampling, unequal probability sampling, stratification. Main focus is on spatially balanced sampling. Spsurvey uses ESRI shapefiles as main input but when it reads them in it creates an sp object. The resulting sample is also an sp object.

Math for GIS

GIS provides a great opportunity to learn math. I recommend continued math study to strengthen your GIS.

How much math does- -gis-analyst-need-to-know