Case introduction

 

Sampling survey to the total area of the forest of Heshun county in Shanxi province in year 2000

 

Description:

We need to take some samples from 2,697,460 image units to investigate (the minimum investigated unit is A TM image) the area of forest coverage of Heshun county in Shanxi province in year 2000, require that the total investigation cost doesn't exceed 100,000 yuan, according to the experience, the standard deviation of each layer unit can be estimated, the base cost of the investigation is approximately 6000 yuan, the average investigated cost of each pixel is 100 yuan.

 

Sampling method:

Stratified sampling

 

Objective:

To estimate the forest area of Heshun county in year 2000 by sampling

 

Condition:

  1. The total cost is 100,100 yuan
  2. The base cost is 6000 yuan ( This cost is the fixed cost that is irrelevant to the sample size, include organization 、 propaganda 、 design of the questionnaire and the necessary device, and so on )
  3. The average investigation cost of each pixel (sample unit) is 100 yuan
  4. According to the experience, standard deviation ( Standard deviation is the root of the mean of sum of squares of deviations, which reflects the dispersion degree of this layer) and investigation cost of each layer can be estimated as follows:
008
Request:
  1. Total optimal sample size and sample size of each layer;
  2. Distribute the samples, namely, extract nh pixel numbers that need to be investigated from each layer;
  3. Calculate, namely, estimate the total forest area and sampling accuracy according to the sampling pixels and investigated data.