How to NOT show decimal values in TileMill when using gdal_contour generated contours?

Question

Following problem has troubled me for two days now and I can't find a solution:

I am using QGIS to generate contour lines from SRTM DEMs. Export these as shapefiles and load them into TileMill on top of a GeoTIFF.

Problem: I can't seem to get rid of the ".0" end of each height (see picture).

This is the carto.css I use:

#kueste_1000 [zoom>=12]{
  line-width:0.6;
  line-opacity:0.5;
  line-color:#c6b69b;
  ::label{
  text-name: [ELEV];
  text-face-name: @sans_italic;
  text-fill: #c6b69b;
  text-placement: line;
  text-min-distance: 400;
    text-dy:10;
  text-size: 12;
    text-opacity:1;
  }
}

I have different contour shapefiles, generated years ago by dem2topo, labelling these works fine.

I thought the problem might be caused by the attribute label, but changing (in gdal_contour command line) the name of the attribute from ELEV to NAME or anything else doesn't do the trick.

I also tried to change the gdal_contour command line:

gdal_contour ... -i 1000.0

to:

gdal_contour ... -1 1000

but this also didn't work.

The funny part is that QGIS, when setting the flag to label these lines, does so without the .0

Answer 1

If you do not care about the decimal in the elevation, try to add a new field with name 'Elevation' in QGIS for the contour line with type 'Integer', Then copy the attribute from the 'Elev' field into the 'Elevation' field, and see if that fix the problem.

Answer 2

Solved!

this is how I did it:

Open attribute table - add new column with integer as type. I left lenghtas 1 and chose HEIGHT as its name

Use the field calculator to update an existing field, select the newly created column, e.g. HEIGHT, type "ELEV" in the lower left expression window. Select OK, the old real numbers (with decimals) are now being copied to the newly formed column without decimals. Select this column in tilemill as the one to select values from.