add readME

README.md

-# map digitalisation for QGIS
+# Map digitalisation for QGIS
+This script can be used, to extract points from a altidude containing TIFF file -- e.g. for species distribution if you only have unprecise locality data.
 
+## How to use
+Execute this script in your parent directory, where each species should have its own subdirectory containing the shapefiles for the dots. Every folder will be processed consecutively.
+
+The altitude TIFF `CHELSA-DEM.tif` should be in the same directory.
+
+Other files will be ignored.
+
+### Example
+```
+parent
+├── Caragana grandiflora
+│   ├── Caragana grandiflora dots.dbf
+│   ├── Caragana grandiflora dots.prj
+│   ├── Caragana grandiflora dots.qpj
+│   ├── Caragana grandiflora dots.shp
+│   └── Caragana grandiflora dots.shx
+├── Caragana ulicina
+│   ├── Caragana ulicina dots.dbf
+│   ├── Caragana ulicina dots.prj
+│   ├── Caragana ulicina dots.qpj
+│   ├── Caragana ulicina dots.shp
+│   └── Caragana ulicina dots.shx
+├── CTS-SWA-INDEX.pdf
+├── CHELSA-DEM.tif
+└── DEM2POINT.R
+```