oco - Orthogonal contours

Name

oco — Orthogonal contours

Syntax

Description

Display orthogonal contours from grids and generate drainage areas.

Arguments

frq frequency

Indicates density of orthogonal contour lines. Default is 7. Lower number gives higher density.

col color

Will be displayed in color color.

liw linewidth

Will be displayed with linewidth linewidth.

bsp

Will smooth the lines with b-splines.

nos

Will not seek for the deepest region (which is default).

noadj

Will not adjust the lines to lay slightly above the grid.

cur

Will produce one ortho contour from the cursor position.

nrg

No regridding or decimation for large grids.

Drainage area calculation
dar

Will produce drainage areas (which is closely related to orthogonal contours).

trm number_of_nodes

Remove drainage areas by minimum _number_of_nodes in areas.

ang angle

Remove drainage areas lower than a certain angle between areas.

cod

Combine two drainage areas defined by the two latest cursor positions.

cdc [lin] [col color]

Calculate a closed drainage curve for an area defined by the latest cursor position. The result curve is saved in workspace draincurve. The curve is smoothed by a spline unless the lin argument is used. Color of the curve can be set by col and color selection.

cdr [smo] [col color]

Calculate closed drainage curves for all drainage areas. The result curves are saved in workspace allcurves. The curve is linear unless the smo is used. Color of the curves can be set by col and color selection.

chd

Change a drainage area defined by the cursor position. This has an expanding effect of the drainge area.

split

Split a drainage area along a line defined by the two last cursor positions just outside the drainage area at opposite positions.

src

The dataset in active is set as the source grid in drainage calculation.

Examples

Ex.1: Orthogonal contours and drainage areas

z                        ;# Erase screen
win demo                 ;# Get demo window (450000 460000 6450000 6460000 1000 4000)
spe bgc whi              ;# Specify background color to white
mak ran 11               ;# Make 11 random points
grp 222 222              ;# Make grid
oco frq 14 col bla liw 2 ;# Draw orthogonal contours
oco dar                  ;# Calculate drainage areas
map drain                ;# Map the drainage areas

The above example produces this image.

Orthogonal contours and drainage areas

See also

cal - Calculation algorithms, mak tan