Preparing smooth maps from sparcely populated Shape files

Tools and Web Services GDAL
1

I have shape file data, which is sparsely populated with rectangular shapes. I would like to make a smooth map using that shape file. Are there tools in GDAL to do interpolation and make smooth maps?

I am very new to handling Geodata. I only have some experience using Geopandas. I would like to know whether there are any existing codes for the above-mentioned process.

Thank you in advance!
Ashish

2

There are some tools (e.g. in ArcGIS) I have seen that can interpolate across polygons, but they are more rare than using a sparse point file as the input type.

So just quickly, there is:

  • gdal_rasterize — GDAL documentation which doesn’t perform any interpolation, just a polygon burn-in to the output raster. So not smooth.
  • gdal_grid — GDAL documentation which has interpolation methods, but uses a point file as input. So it can create a smooth output but requires points not polygons.
  • lots of other point interpolation options in QGIS (e.g., GRASS, SAGA, etc. plug-ins)

So what to do? Perhaps you could convert your polygons to points. Here are 4 methods to do that (e.g., center, outside vertices, inside regular grid, …) Polygon To Points In QGIS - August 8, 2024 (mapscaping.com). In your case, if centroids don’t work, I might try Method 3.

3

What do the data in the shapefile represent? Is it appropriate to convert the vector data to raster and smoothly interpolate between them?