On 1/15/06, Carola Jesch <[EMAIL PROTECTED]> wrote: > Hi, > > I have an contineous ASCII GRID (floating values) that I would like to > display in MapServer. This grid shows bathymetry (ocean) and elevation > (land) data. There are a lot of negative values for the ocean, starting from > -1500 to 0 and only a small range for the land (0 to 20). When I am trying > to display the grid, the entire image is black. Does MapServer support > negative values? How can I display the grid with colors? > I have tried to convert the Ascii file to a binary grid, but I don't know > how to create a colormap (*.clr). ArcGIS doesn't seem to support this or > does anyone of you how to do that?
Carola, By default Mapserver will read the grid values directly, and clip any values outside the range 0 to 255 the bounds. So all your negative values are cliipped to zero, and the top value is 20 (out of 255) which would appear nearly black. The first step I would suggest is enabling autoscaling with the layer directive: PROCESSING "SCALE=AUTO" Beyond that I would suggest you review the raster howto. http://mapserver.gis.umn.edu/docs/howto/raster_data Best regards, -- ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, [EMAIL PROTECTED] light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush | Geospatial Programmer for Rent
