我想根据距居民和道路的距离（两个差异地图）创建火灾风险栅格。使用erdasimagine或qgis或任何其他软件（如果可能的话，开源）的任何建议？ 例子
Data : Dem.img , residents.shp (point)
Wanted Output : ThematicRaster.img
Output Values :1-5 (where 1=Very Low risk=> Distance from residents>2000m
2=Low_Risk => Distance from residents(1000,2000])
I believe that the solution will be pretty much the same for linear data.