Click her to go to 'Figures/Overheads' section.
Click here to return to course outline.
Follow same procedure for BE_HYD, extracting streams
(only) as lines into a vector
file STREAMS (attribute value of `1'). Create a line symbol file `streams' with `1' as
blue. Extract marshes (attribute value `1') and lakes and ponds (attribute value `2') as
area (polygon) features into WATERBOD, and construct an appropriate polygon
symbol file `waterbod'.
Importing the DEM raster files.
Run DEMIDRIS (Files/Import/US Goverment Data Formats); import BLKEAR.DEM;
output DEM. Display with the Idrisi 256 palette, and autoscale. Check the HISTO
distribution and then set the minimum value in the .doc file to the minimum non
background value ; in this case querying the cell values will give the real elevation
values and not the palette value [0-255]). Change the colour number 0 in the idrisi256
pallete to white and save as a BLKEARTH palette file. Display the image with the new
Layer ROADS over DEMC. The raster and vector images are not registered because
DEMC is a NAD83 datum image and ROADS is a UTM NAD27 datum image.
Exercise 17 - Changing the Reference system with PROJECT
Run PROJECT (in Reformat)
and input STREAMS; use STREAMS83 as the
output file name, and US83TM16 as the output reference system. Same for ROADS and
Read page 13-105 regarding the error characteristics of the UTM coordinate system.
Figure 1. Plate Tectonics.
Click here to return to beginning.