User's guide of Proceessing Modflow 5.0

184 Processing Modflow
< To zoom in on a part of the model
1. Click the Zoom In button .
2. Move the mouse cursor to where you want a corner of the "Zoom" window.
3 Drag the mouse cursor until the window covers the model area which is to be displayed.
4. Release the mouse button.
Zoom Out
Clicking on the "Zoom out" button forces PMPATH to display the entire model grid.
Particle color
Clicking on the Particle color button allows a user to select a color for new particles from a
Color dialog box. Particles with different colors are useful when, for example, you want to
determine the capture zones of several pumping wells. In this case, particles with a certain color
are placed around or on the cell-faces of each pumping well. Through backward tracking, capture
zones of each pumping well can be recognized by their different colors.
Run particles backward
Click this button to execute backward particle tracking for a specified time length. The time
length is the product of the number of particle tracking steps and the particle tracking step length
given in the Particle Tracking (Time) Properties dialog box. See sec. 4.3 for details.
Run particles backward step by step
Click this button to move particles backward a single particle tracking step. The particle tracking
step length is defined in the Particle Tracking (Time) Properties dialog box. See sec. 4.3 for
details.
Stop
You can click the Stop button to stop particle tracking or stop redrawing particles when the Stop
button is highlighted (ie, the rectangle on the button is colored in red).
PMPATH redraws the particles whenever the PMPATH window has been covered by other
windows and becomes visible again. For example, if you change to another application and then
return to PMPATH, PMPATH will redraw all particles. If too many particles are placed, you will
need to keep PMPATH from redrawing all particles. Under some circumstances, PMPATH will
take a long time for calculating the coordinates of flow paths and travel times. This is especially
true, if the flow velocities and the user-specified time step length of particle tracking are very
4.2 PMPATH Modeling Environment