Many a times, in your analysis, you might need to extract values from rasters based on point locations. The Spatial Analyst extension offers several tools that can do this for you, those being Extract Values to Points, Extract Multi Values to Points and Sample. However, because there are some similarities between them, you may be confused about which one to use. Read on more to find out how to choose the right tool.
Before you start your analysis, let’s ask a few questions:
Answering such questions before hand will help you determine the best way to perform your analysis.
Which tool to choose for your analysis?
Let’s take these questions and have a look at how Extract Values to Points, Extract Multi Values to Points and Sample tools are different from each other.
Questions | Extract Values to Points | Extract Multi Values to Points | Sample |
Does the tool support single raster or multiple rasters as input? |
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If the input raster is a multiband, does the tool execute on the first band or all bands? | The first band | All bands | All bands |
What is the output? | Creates a new feature class | Appends raster values to the input feature class | Creates a table |
Dose the tool support appending all raster attributes? | Yes | No | No |
When interpolated, what method is supported? |
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This table gives the basic guidance on deciding which tool to use. A few other things to keep in mind are:
Let’s look at some use cases.
Use Case 1. Extract values from single raster at point locations
Say, you have some meteorological observation sites, and you would like to know the elevation of these locations.
For this case, the input would be a single elevation raster. You could use any of these three tools, since they all support single raster. Which one to use depends on what kind of output you need. For example, if you need to attach the elevation values to the input feature class’s attribute table, just use Extract Multi Values to Points.
Use Case 2. Extract values from multiple rasters at point locations
Assume, you want to learn the impact of corn production factors using regression. You have sampling locations, and you would like to extract the values of several factors at those locations, such as, temperature, soil moisture, plant population and Nitrogen supply.
For this case, you would need to extract values from multiple rasters at point locations. Both Extract Multi Values to Points and Sample can do this for you, so use your preferred output format, feature or table, to pick the one to use.
Tips
In addition, you might consider the following for your analysis:
Now you know how to best choose the appropriate extraction tool for your analysis. Let us know what you think about it.
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