1 / 11

Grid Functions

Grid Functions. FE 423 - Lecture 3b. SCHEDULE. OUTLINE. Grid Function List Writing Equations Conditional Setnull/Isnull Local/Focal/Zonal Functions Project/Disc Management. Grid Function List. ArcView Help: Grid (Class) We only use those ending in :Grid and not those with Ftab

mab
Télécharger la présentation

Grid Functions

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Grid Functions FE 423 - Lecture 3b

  2. SCHEDULE

  3. OUTLINE • Grid Function List • Writing Equations • Conditional • Setnull/Isnull • Local/Focal/Zonal Functions • Project/Disc Management

  4. Grid Function List ArcView Help: Grid (Class) • We only use those ending in :Grid • and not those with • Ftab • aPrj • aGridList

  5. WRITING EQUATIONS In math: y=x2 Old computer code y=sqr(x) Object oriented code [x].sqr Nesting log(sin(x))  [x].sin.log parameters [dem].hillshade(315,45,1)

  6. Conditional Statement0/1 to grid0/grid1 • If condition • then action1 • else action0 • in Avenue aGrid.Con (yesGrid, noGrid) • Example ([snow]>[melt]).Con(([snow]-[melt]),0.Asgrid)

  7. Null Data • Cells with no value (not 0) are null Some functions require null cells Some functions make null cells • Setnull: sets specific cells to null ([stand age]>100.Asgrid).SetNull([stand age]) • Isnull: is a cell value null? ([landslides].Isnull).Con(0.Asgrid,1.Asgrid)

  8. Local/Focal/Zonal Functions • Local Functions at each cell [grid1]+[grid2] • Focal Functions around each cell [dem].FocalStats(#GRID_STATYPE_MEAN, NbrHood.Make, False) • Zonal Functions within the zone of each cell ([dem]>1000.asgrid).ZonalFill([dem])

  9. PROJECT MANAGEMENTevery project tells a story • Make project name explanatory • Make themes name explanatory • Make legend categories clear • Comment themes to explain thinking • Remove useless themes • Separate unrelated themes by project

  10. DISC MANAGEMENTmake and move everything together • Use one directory on all machines C:/temp/email_name/this_project/ • Set Working Directory • Save coverages, files, project, report • zip directory to move • by network • by zip drive • email/ftp

  11. Reading from ArcDoc • Spatial modeling • Cell-based Modeling with GRID • Surface hydrologic analysis

More Related