# Does interpolation create a vector or raster?

I have been reading about interpolation and am trying to understand whether interpolation results in a vector or raster. Say I have a layer of points and I am interested in creating a raster that fits a known grid (aligns with another raster). Do I interpolate and then convert to the raster or is raster conversion a part of the interpolation process?

Edit:

I have point vector data and a raster, so I am trying to convert my point data to a raster. From what I have read interpolation is a reasonable thing to do when converting points to a raster.

My data is stored in a PostgreSQL database, so I am trying to use Python and QGIS. I am pretty familiar with Python but not so much with this type of processing since most of the data I work with is typically tabular.

• Interpolation can create both. TIN and voronoi polygons create a vector, than IDW and Krigging usually output a raster. You might prefer a raster output if you are dealing with a raster-based analysis. Please edit your question and specify what gis software you are using, to get an informed answer – dof1985 Mar 20 '15 at 15:13
• You can interpolate straight to a raster. However, whether is appropriate and how you approach the process (e.g. IDW, Kriging, TIN, RST etc) will depend on your data. I suggest you rephrase your question explaining what data you have and what raster you want/need (and how you intend to use it) and that way you may get a more informed answer as to which interpolation method might be suitable, otherwise this question is too open. – MappaGnosis Mar 20 '15 at 16:07
• Iterpolation is mainly a prediction method, that is if you want to predict a surface from a point - you use interpolation. As @MappaGnosis mentioned, for informed answeres you need to clarify what are your intentions, do you want to predict a phenomena? what is the phenomena? or you just want a raster from points with no prediction. You might find this thread helpful – dof1985 Mar 20 '15 at 16:31
• When they're asking about what your data is, they mean subject not format. Some interpolation methods are more suitable to some kinds of data (say rainfall measurements) than others (like elevation). For example: resources.arcgis.com/en/help/main/10.1/index.html#/… In your case, yes, you'll probably want to go straight from points to raster to match your other rasters, but how you do that depends on what kind of data you're working with. There are a number of questions here on selecting an interpolation method and what is 'best'. – Chris W Mar 20 '15 at 20:38