Dear all,
I am having a raster (prepared by interpolating some point data) which doesn't coincide with the boundary of the study area. That means, there is gap between the study area boundary and the edges of the raster. I want to fill this gap to get a raster clipped to the study area boundary. Just to mention, this problem arose due to the absence of points around the margins of the study area boundary.
Does anybody know the procedure to do this? Also, I would like to know if extrapolating raster is a right thing to do or there exists other ways to deal such data scarcity issues? Any help shall be appreciated.
-
Best Regards
Akanksha
Hi Akanksha,
I am not sure in which program you are doing the interpolation. Given the nature of your problem, it is typically an issue of the default setting for the extent of your area. This needs to be specified specifically. In ArcGIS for example you can define the geoprocessing environment. In these settings you have an option to define the extent. You can set the extent to coincide with your study area. Note that if your study area is not a a rectangle, you also have the option to define a mask. The interpolation will then only be carried out for your study area (you still need to define the extent separately).
I hope this helps,
Jetse
Thanks Jetse!! It is successfully done. I have been doing it in ArcGIS only.
Akanksha
This might help you;
https://gis.stackexchange.com/questions/83298/only-interpolating-within-a-polygon-feature-in-arcmap-10-1
Hi
Following the Jetse suggestion, I found the following method works. In my case, I needed to extrapolate raster files to outer extent boundaries:
- Set the extent desired for the raster files. Use the extent of an (shp) polygon that defines the limits you want. I used the function setExtent in R, and save the raster output.
- Interpolate each raster obtained from the previous step using the "close gaps" SAGA tool in QGIS
In the first step, it could be some displacement of the raster's pixel (60 meters in my case). So the output of this step requires to be checked if the change is acceptable or not before its application.
Hope it helps, Albert
- Badges
- Science topic
- Similar topics
- Psychology