Week of Jan. 15

1. Week of Jan. 15 • Today’s agenda: • Announcements & reminders • MFworks operations • Give out assignment#2 • Continue work on assignment#1

2. Announcements & Reminders • Still working on the printers • Assignment #1 is due next week at the beginning of the lab • Assignment #2 will be due week of Feb.5 • Lab Supervisor orientation meeting this Thursday afternoon (Jan. 18)

3. Does anyone need help formating a PC Zip disk for the Mac?

4. Important raster GIS concept • Data is numeric • Operations work on the data not the map colours

5. MFworks operations and functions • Cover • Recode • Slice • Spread • Clump • Count function

6. Operation Taxonomy • Group 1: Basic operations on 1 Layer • Explicit renumbering (= Recode) • Automatic renumbering (=Slice) • Basic measurement (=Spread) • Adjacency assessment (=Clump) • Group 2: Basic operations on n layers • Layer superimposition (=Cover)

7. Cover operation • A Group2 operation: Layer Superimposition • The Cover operation is used for two main purpose: 1) overlaying map layers 2) for mosaicking map layers

8. Cover operation overlay statement format Newmap = Covermaplayer1 withmaplayer2 withmaplayer3 ;

9. 3 Cover 2 1 Newmap Newmap = Cover maplayer1 with maplayer2 with maplayer3 ;

10. Cover operationmosaic statement format Newmap = Covermaplayer1 withmaplayer2 mosaic ;

11. 1 Cover mosaic 2 Newmap Newmap = Cover maplayer1 with maplayer2 mosaic ;

12. Recode operation • A Group 1 operation: Explicit Renumbering • Generates a new map layer • You specify the zones from the input map that will appear in the output map • Use the “…” operator for specifying number ranges (from the keypad menu in the script window)

13. Recode statement format newmap = Recodeoldmap AssigningnewvalueToexistingvalue ; Existingvalue is a number from the legend of the oldmap

14. Recode modifiers newmap = Recodeoldmap AssigningnewvalToexistvalAssigningnewval2Toexistval2…existval3 Assigningnewval3Toexistval4 … Assigningnewval4To … existval5 Assigningnewval5To … CarryOver ;

15. Slice operation • A group 1 operation: Automatic Renumbering • Slice may be thought of as an “automatic” recode

16. The concept of “Slice” • It divides the range of values in an input map into equal sized groups • Each group becomes a zone in the output map

17. An example of the Slice in action Here is a map

18. The legend for this map looks like this

19. The same map after being sliced into 5

20. The resulting legend has only 5 zones

21. Slice operationstatement format Newmap = Sliceinputmapintovalue ;

22. modifiers of Slice Newmap = Sliceinputmapintovalue by value rangevalue range use topvalue use middlevalue use bottomvalue makerangelabels ;

23. Spread operation • A Group 1 operation: Basic Measurement • Measures distances from specified cells

24. Spread statement format newmap = Spreadoldmap Tomaximum distance ; Spread will measure the distances starting from any non-void cells in the input map.

25. Clump • A Group 1 operation: Adjacency Assessment • “Clump” is used to group together or join together cells From the MFworks guide: “The Clump operation creates a map layer in which cells with the same value, within a specified distance of each other, are assigned a common unique value.”

26. Format of the Clump operation NewMap = ClumpinputmapatDistance ;

27. The Clump in action What will be grouped if we run clump at a distance of … 1 ? 1.5 ? 3 ?

28. Clumped at distance 1 Before After

29. Clumped at distance 1.5 Before After

30. Clumped at distance 3 Before After

31. Another new item:The Count function Area field Value field Thisfunction produces a new map where the number of cells in each zone in the old map becomes the value for that zone in the new map. It measures Zone Area

32. The Count in action NewMap = Count (inputmap) ; Inputmap Legend New Map Legend

33. Binary Maps • The binary number system is commonly used in computer science applications. We often use it in GIS. • Map examples: • Rural or Urban zones • Man made or Natural • Land or Water areas

34. A mask map is a special type of binary map • Both mask maps and binary maps have only 2 zones. • Binary maps are typically something and something else • Mask maps are something and VOID

35. When to use masks • Masks are used to restrict GIS operations to a specific area • Masks are used to ‘blot’ out areas or regions in a map

36. Assignment #2 • Gain experience working with Basic Operations (I and II) as they are implemented in MFworks • Also develop • Scripting skills • Spatial processing • Cartographic layout and design • Problem solving

37. 2 part assignment • Part 1 - work on Spatial Relations. Measuring distances and areas • Part 2 - concept of Competing Distances and cartographic visualization.

38. Advice • Work on this assignment on your own • You will get more out of it if you try to develop your problem solving skills • You will need the experience with writing scripts and the concepts of the operations when it comes to exam time

39. Read over the entire assignment before beginning it • Familiarize yourself with the structure of it • Note the section at the back on output tips and try to apply them to your layouts

40. Things to remember from last week • Keep your files organized - make an Assignment#2-yourname folder for this assignment

41. That’s all • Use the time to finish up Assignment #1 and maybe start Assignment #2 • The lab should be open starting next week for drop in work sessions