creating raster from a csv file

[mintiayele]

Dear all,

I am new to arcgis (have the education Edition of arcgis) and am trying to create a raster layer from a csv file. The csv file has latitude and longitude and what I did so far is to read my csv file into arcmap and create a shape file. Then I used the spatial analysist tools, create normal raster and I think created a raster. but the raster looks like a collection of tiles with points (from my shapefile ) on top of it. Is that how it is supposed to look like? And when I read the raster in r , it is not giving me the results I expect.

Now what I cannot tell is whether what I did to create the raster is indeed right.

Suggestions appreciated
Thanks
minti

[PetronilaMandeno]

What do the points represent? Is there data associated with those points, like elevation or chemical concentration or some other numeric value? Or do they represent something like vegetation type?

Now, why do you want the data in raster format? If the points have elevation data associated with them, is your aim to create a topographic surface? In that case, you'll probably want to use one of the Interpolation tools in the Spatial Analyst Tools in ArcToolBbox. I've always used the Topo to Raster (using contour lines, of course), but I'm sure you can get similar results with the IDW or Kriging tools to interpolate those values across a surface.

Did that help?

[mintiayele]

Dear Esther,


Thanks for your suggestion. That is probably what I need to do but let me lay out my whole problem. I have station level rainfall data and I want to get that interpolated at a farm level. So what I have is station locations (latitude, longitude), rainfall, and farm locations (latitude, longitude and altitude). Now what I want to do is create a raster for my farm locations. Once I do that I will do the interpolation of the station level rainfall data in R. The reason I want to have the raster only from arcmap is because I am not very familiar with arcgis and I also only have a student edition, which I thought might restrict me from using different tools. So is it possible for me to get a raster from my farm locations?

Regards,

Minti

[JeffreySwain]

I would take a look at the interpolation tools in Spatial Analyst to create the output.  You will not want to convert the points to a raster and then do the interpolation.  You will need to keep the csv as points and then use them in one of the interpolation tools. I am not sure what 'R' is, but all the tools are available with Spatial Analyst to create your raster.

[mintiayele]

Thanks Jeff. So I am sure what I am doing makes sense, I will do the interpolation using station latitude and longitude and rainfall observations. How would I use my farm level location information then (those would be the points I want my interpolated results to correspond to ) ?

Regards,

Minti

[mintiayele]

Dear all,

I have a followup question to my earlier request. How do I activate spatial analyst? I have added the extension but I do not see the tools icon that would take me to spatial analyst

regards
minti

[PetronilaMandeno]

Dear all,

I have a followup question to my earlier request. How do I activate spatial analyst? I have added the extension but I do not see the tools icon that would take me to spatial analyst

regards
minti

Go to Customize (in the menu bar) then Extensions. Click the little box next to the extension you want to use then close the dialog box. You should be able to turn on the Spatial Analyst tool bar after that (right click on the menu bar, then scroll down the list of tool bars.

Also, the idea is to calculate the rainfall at your farms, right? That's the question you want to answer?

Once you interpolate the rainfall values over an extent that covers your farms, then you can extract the values from the interpolated surface to your farm points. (Look up Extract Point Values)