I have a (potentially) large data set stored in MongoDB. Each record is just
lon and some float-point
value. Each pair of
lon is unique, but the whole set is not covering the Earth, there may be regions with no data at all (so they're not stored).
I need to draw my own tiles based on this data, where mentioned
value displayed with respective color (say, from black for minimal values to white for maximal). My dataset is changing in time, so I have to re-render tiles periodically.
I've installed GDAL but I can't find a way to fetch the data.
I've tried to export points to XYZ format, but got no luck:
gdal2tiles.py doesn't want to work with it (I think the cause is that my coords are not sequential: I found a sample XYZ data set in Internet, and it was converted OK, and the only difference is that file had a value for each node in grid). Maybe it will work if I populate my database with some initial values for each possible coords pair, but it will cost much time, disk space and DB performance, so it's the last resort.
How can I make this stuff work? What am I doing wrong? Is there something to read that will help me?