Prepared by David R. Maidment
What we want to do now, is to add new attributes to the map unit table which summarise for each map unit the percentage of that map unit occupied by soil groups A, B, C, D. To do this for each map unit we have to total up the values of comppct over all components having a particular soil group. This is easier said than done because of the one to many relationship between the map unit and component tables and because for each map unit there is a cumulative calculation involved of the values of Comppct based on the value of field Hydgrp. We are going to use a calcuation defined over a relation to accomplish this task.
In Arc/Info, adding attributes value is accomplished by first defining what the new attributes will look like when displayed in the map unit table and then by determining the value that is to be stored in each record of the attribute.
Arc: tables [this starts up the Tables system]
Arc: tables
Copyright (C) 1982-1995 Environmental Systems Research Institute, Inc.
All rights reserved.
TABLES Version 7.0.3 (Mon Mar 13 22:21:55 PST 1995)
First, lets check out what tables are available:
Enter Command: dir
TYPE NAME INTERNAL NAME NO. RECS LENGTH EXTERNL ------------------------------------------------------------------------------ DF COVSHD10.TIC ARC0000DAT 4 12 XX DF COVSHD10.BND ARC0001DAT 1 16 XX DF COVSHD10.PAT ARC0002DAT 67 20 XX DF COMP ARC0003DAT 5579 292 DF MAPUNIT ARC0004DAT 631 142 DF LAYER ARC0005DAT 17102 240 DF SOILSHED.TIC ARC0006DAT 1343 12 XX DF SOILSHED.BND ARC0007DAT 1 16 XX DF SOILSHED.PAT ARC0008DAT 88 24 XX DF RF1SHED.TIC ARC0009DAT 4 12 XX DF RF1SHED.AAT ARC0010DAT 72 170 XX DF RF1SHED.BND ARC0011DAT 1 16 XX
The mapunit and comp tables are the ones that you need to work with next. take a look at the attributes (items) in each of the information tables that you copied:
Enter Command: select mapunit
631 Records Selected.
[there are 631 map units in Texas]
Enter Command: items
COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME INDEXED?
1 STSSAID 5 5 C - -
6 SSAID 3 3 C - -
9 MUSYM 5 5 C - -
14 MUID 7 7 C - -
21 MUNAME 109 109 C - -
130 MUKIND 1 1 C - -
131 MLRA 4 4 C - -
135 PRIMFML 2 2 C - -
137 MUACRES 6 6 I - -
COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME
In this description, Width is the number of characters assigned to the field, Output is the number of characters used to display the field, Type N.Dec is the type of data (C = character, I = integer, N = floating point, .dec = number of decimal places, Alternate name is an alias for the field. Notice that Muname has a very wide field to accomodate the grouping of component names to form a map unit name.
Enter Command: select comp
5579 Records Selected. [there are 5579 components in Texas; 5579/631 ~ 9 components per map unit]
Enter Command: items
COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME INDEXED?
1 STSSAID 5 5 C - -
6 MUID 7 7 C - -
13 SEQNUM 2 2 I - -
15 MUSYM 5 5 C - -
20 COMPNAME 30 30 C - -
50 S5ID 6 6 C - -
56 COMPPCT 3 3 I - -
59 SLOPEL 2 2 I - -
61 SLOPEH 2 2 I - -
63 SURFTEX 8 8 C - -
71 OTHERPH 40 40 C - -
111 COMPKIND 1 1 C - -
112 COMPACRE 6 6 I - -
118 CLASCODE 20 20 C - -
138 ANFLOOD 5 5 C - -
143 ANFLODUR 12 12 C - -
155 ANFLOBEG 3 3 C - -
158 ANFLOEND 3 3 C - -
161 GSFLOOD 5 5 C - -
166 GSFLODUR 12 12 C - -
178 GSFLOBEG 3 3 C - -
181 GSFLOEND 3 3 C - -
184 WTDEPL 4 4 N 1 -
188 WTDEPH 4 4 N 1 -
192 WTKIND 5 5 C - -
197 WTBEG 3 3 C - -
200 WTEND 3 3 C - -
203 PNDDEPL 4 4 N 1 -
207 PNDDEPH 4 4 N 1 -
211 PNDDUR 10 10 C - -
221 PNDBEG 3 3 C - -
224 PNDEND 3 3 C - -
227 ROCKDEPL 2 2 I - -
229 ROCKDEPH 2 2 I - -
231 ROCKHARD 4 4 C - -
235 PANDEPL 2 2 I - -
237 PANDEPH 2 2 I - -
239 PANHARD 5 5 C - -
244 SUBINITL 2 2 I - -
246 SUBINITH 2 2 I - -
248 SUBTOTL 2 2 I - -
250 SUBTOTH 2 2 I - -
252 HYDGRP 3 3 C - -
255 FROSTACT 8 8 C - -
263 DRAINAGE 5 5 C - -
268 HYDRIC 1 1 C - -
269 CORCON 8 8 C - -
277 CORSTEEL 8 8 C - -
285 CLNIRR 1 1 C - -
286 CLIRR 1 1 C - -
287 SCLNIRR 2 2 C - -
289 SCLIRR 2 2 C - -
291 PRIMFML 2 2 C - -
** REDEFINED ITEMS **
6 MUSEQ 9 9 C - -
You'll notice that you need to "select" the table you want to investigate prior to looking at the items in that table. (In the COMP table, note that the items beginning at columns 56 and 252 are COMPPCT and HYDGRP. You'll use these items a little later)
Now you are going to add hydrologic soil group data to the Mapunit table. There are 7 established STATSGO soil group types for Texas: A, B, C, D, A/D, B/D, and C/D. The latter three types are soils which are D soils unless they are drained, in which case they become types A, B, C, respectively. There are very few instances of these types of soils in Texas, so we will not deal with them in this exercise.
For each STATSGO polygon, you want to know what percentage of the polygon makes up each of these soil group types. First, using the additem command, add fields to the Mapunit table for the percentage of each soil group type:
Enter Command: select mapunit
631 Records Selected.
Enter Command: additem mapunit A_pct 3 3 i
Cannot add items to an open file.
With this command you are literally saying: add to the table called mapunit an item called A_pct that will be 3 characters wide, will need 3 characters of display width, and is an integer. However, Arc/Info will not let you modify a table that you have "selected". If you select another Table (e.g. Comp), then you will be able to modify Mapunit (strange but true). Or, you can leave Tables and come back in and modify Mapunit without selecting any table:
Enter Command: quit
Leaving TABLES...
Arc: tables
Now, lets add the items for the percentage of each map unit occupied by A, B, C, D:
Enter Command: additem mapunit A_pct 3 3 i
Enter Command: additem mapunit B_pct 3 3 i
Enter Command: additem mapunit C_pct 3 3 i
Enter Command: additem mapunit D_pct 3 3 i
Enter Command: select mapunit
631 Records Selected.
Enter Command: items
COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME INDEXED?
1 STSSAID 5 5 C - -
6 SSAID 3 3 C - -
9 MUSYM 5 5 C - -
14 MUID 7 7 C - -
21 MUNAME 109 109 C - -
130 MUKIND 1 1 C - -
131 MLRA 4 4 C - -
135 PRIMFML 2 2 C - -
137 MUACRES 6 6 I - -
143 A_PCT 3 3 I - -
146 B_PCT 3 3 I - -
149 C_PCT 3 3 I - -
152 D_PCT 3 3 I - -
Now you can see that the 4 items added to the mapunit table actually do show up. Next you'll want to relate the component table (Comp) to the mapunit table (i.e associate attributes from Comp to Mapunit). We are here doing in Arc/Info the same kind of thing that you did earlier in Arcview when linking the two tables (Comp is the "Source" table and Mapunit is the "Destination" table).
Enter Command: select comp
5579 Records Selected.
Enter Command: relate add
Relation Name: mu
Table Identifier: mapunit
Database Name: info
INFO Item: muid
Relate Column: muid
Relate Type: ordered
Relate Access: rw
Relation Name: Hit Return key here
Once you've narrowed down the selected table (Comp) , you will sum the percentages (comppct) for all records associated with a specific map unit. This is a bit tedious and you need to be careful with your typing!
Enter Command: reselect hydgrp = 'A'
[this is a reduce/select command that narrows our selected table (Comp) down to only the records that have a value of 'A' for the item hydgrp]
285 Records Selected.
Enter Command: calc mu//A_pct = mu//A_pct + comppct
Be sure to leave spaces on each side of the = sign and the + sign or the calculation won't work.[this "calculate" command says "For each map unit in the mapunit table, determine the value of the total percentage of STATSGO soil type A, by summing all of the component percentages for each component with a particular map unit id". The // nomenclature means that the value of A_pct is in the related destination table while the comppct comes directly from the selected table]
Enter Command: select comp
Enter Command: reselect hydgrp = 'B'
1792 Records Selected.
Enter Command: calc mu//B_pct = mu//B_pct + comppct
Enter Command: select comp
Enter Command: reselect hydgrp = 'C'
1539 Records Selected.
Enter Command: calc mu//C_pct = mu//C_pct + comppct
Enter Command: select comp
Enter Command: reselect hydgrp = 'D'
1944 Records Selected.
Enter Command: calc mu//D_pct = mu//D_pct + comppct
Now you have specified the formulas for all of the new items that you've added to mapunit. You may now look at some representative values of the different STATSGO hydrologic soil type percentages:
Enter Command: select mapunit
631 Records Selected.
Enter Command: list muid A_pct B_pct C_pct D_pct
[this command says "For mapunit, list the map unit id and all soil type percentages"]
Record muid A_pct B_pct C_pct D_pct
1 TXW 0 0 0 0
2 TX001 0 0 0 0
3 TX002 0 85 10 5
4 TX003 0 89 11 0
5 TX004 0 50 9 41
6 TX005 0 54 46 0
7 TX006 0 15 36 49
8 TX007 0 0 33 67
9 TX008 0 8 66 26
10 TX009 0 53 47 0
11 TX010 0 5 0 95
12 TX011 0 40 45 15
13 TX012 84 1 13 2
14 TX013 0 95 5 0
15 TX014 0 96 4 0
16 TX015 0 40 30 30
17 TX016 3 93 2 2
18 TX017 0 11 89 0
19 TX018 0 18 82 0
20 TX019 0 4 93 3
21 TX020 0 14 70 16
22 TX021 0 0 94 6
Continue?
(type y to see more data or n for no or (return) to look at the next block of data.
If you type y you will see all 631 mapunit results!)
Here is the result for mapunit TX560 that you examined earlier:
556 TX560 0 28 3 69
Each row of numbers should add up to 100 %. If so, then you have successfully appended your mapunit table with soil type group data!!
Enter Command: quit
Leaving TABLES...
At the beginning of the exercise, you used a polygon coverage called soilshed clipped from the statsgo and covshd10 polygon coverages. All polygon coverages have polygon attribute tables (pat). Let's take a look at the items in the attribute table for soilshed:
Arc: items soilshed.pat
COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME INDEXED?
1 AREA 4 12 F 3 -
5 PERIMETER 4 12 F 3 -
9 SOILSHED# 4 5 B - -
13 SOILSHED-ID 4 5 B - -
17 MUID 7 7 C - -
** REDEFINED ITEMS **
19 IDS 3 3 C - -
Next you'll want to take the data from mapunit and attach it to this Polygon
Attribute Table:
Arc: joinitem soilshed.pat mapunit soilshed.pat muid muid
Joining soilshed.pat and mapunit to create soilshed.pat
[this command says "attach to soilshed.pat the items from mapunit and call the resulting output soilshed.pat (i.e. redefine soilshed.pat). Associate the items based on the relate item muid. Place these new items immediately following the item, muid, in soilshed.pat]
Arc: items soilshed.pat
COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME INDEXED?
1 AREA 4 12 F 3 -
5 PERIMETER 4 12 F 3 -
9 SOILSHED# 4 5 B - -
13 SOILSHED-ID 4 5 B - -
17 MUID 7 7 C - -
24 STSSAID 5 5 C - -
29 SSAID 3 3 C - -
32 MUSYM 5 5 C - -
37 MUNAME 109 109 C - -
146 MUKIND 1 1 C - -
147 MLRA 4 4 C - -
151 PRIMFML 2 2 C - -
153 MUACRES 6 6 I - -
159 A_PCT 3 3 I - -
162 B_PCT 3 3 I - -
165 C_PCT 3 3 I - -
168 D_PCT 3 3 I - -
** REDEFINED ITEMS **
19 IDS 3 3 C - -
You'll notice that the items from the mapunit table are located immediately following the item item muid in the soilshed.pat.
Lets check out what soil polygons we have with soil TX560 in them:
Arc: tables
Copyright (C) 1982-1995 Environmental Systems Research Institute, Inc.
All rights reserved.
TABLES Version 7.0.3 (Mon Mar 13 22:21:55 PST 1995)
Enter Command: select soilshed.pat
88 Records Selected.
Enter Command: reselect muid = 'TX560'
5 Records Selected. [There are 5 soil polygons in this area containing a soil
association described by map unit
TX560]
Enter Command: list
5
AREA = ************
PERIMETER = 408095.281
SOILSHED# = 5
SOILSHED-ID = 12570
MUID = TX560
STSSAID =
SSAID =
MUSYM =
MUNAME = TINN-PURSLEY-GOWEN (TX560)
MUKIND =
MLRA = 86A
PRIMFML =
MUACRES = 0
A_PCT = 0
B_PCT = 28
C_PCT = 3
D_PCT = 69
8
AREA = 648.901
PERIMETER = 123.008
SOILSHED# = 8
SOILSHED-ID = 12570
MUID = TX560
STSSAID =
SSAID =
MUSYM =
MUNAME = TINN-PURSLEY-GOWEN (TX560)
MUKIND =
MLRA = 86A
PRIMFML =
MUACRES = 0
A_PCT = 0
B_PCT = 28
C_PCT = 3
D_PCT = 69
Look at a few different records in soilshed.pat. Many of the items in each record consistently have no entered values (not even zero!). Since there is no real value added from these items, you may choose to eliminate them from the table. Quit out of Tables and then restart Tables again.
Enter Command: quit
Arc: tables
Enter Command: dropitem soilshed.pat stssaid
Enter Command: dropitem soilshed.pat ssaid
Enter Command: dropitem soilshed.pat musym
Enter Command: dropitem soilshed.pat mukind
Enter Command: dropitem soilshed.pat primfml
Enter Command: dropitem soilshed.pat muacres
Enter Command: quit
Arc: items soilshed.pat
COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME INDEXED?
1 AREA 4 12 F 3 -
5 PERIMETER 4 12 F 3 -
9 SOILSHED# 4 5 B - -
13 SOILSHED-ID 4 5 B - -
17 MUID 7 7 C - -
24 MUNAME 109 109 C - -
133 MLRA 4 4 C - -
137 A_PCT 3 3 I - -
140 B_PCT 3 3 I - -
143 C_PCT 3 3 I - -
146 D_PCT 3 3 I - -
** REDEFINED ITEMS **
19 IDS 3 3 C - -
You can now see that the pat for soilshed has been modified and includes only those items that have numerical values.
The coverage soilshed includes all of the STATSGO polygons within the COVSHD10 watershed perimeter. Soilshed does not, however, contain the borders between subwatersheds. To get that data included all in one coverage, you'll need to do the following:
Arc: intersect soilshed covshd10 soilstat
[this command says to merge the attributes of soilshed and covshd10 (including the
ID #'s) and place them in a new coverage called soilstat. You may choose to just merge the two coverages back into soilshed, in which case the final argument in the command line would be soilshed instead of soilstat]
Intersecting soilshed with covshd10 to create soilstat
Intersecting soilshed with covshd10 to create soilstat Sorting... Intersecting... Assembling polygons... Creating new labels... Creating soilstat.PAT... ** Item "AREA" duplicated, Join File version dropped ** ** Item "PERIMETER" duplicated, Join File version dropped ** ** Item "AREA" duplicated, Join File version dropped ** ** Item "PERIMETER" duplicated, Join File version dropped **
Ok! Now you've got three coverages: soilshed, covshd10 and their intersection soilstat
$Arc: quit
To be turned in: List the item fields in the .pat tables of each of the three coverages. How many fields and records does each coverage have? What happens when you intersect soilshed and covshd10 to produce Soilstat? How many new fields are created? How many new records are created?
In the above exercise, you compiled STATSGO soil properties from the comp table to the statsgo polygon attribute table and determined their values for a particular watershed. To get properties from the Layer tables, you have first to transfer them to the Comp table and then to the Mapunit table. Because it takes two relate items (muid and seqnum) to uniquely specify a soil layer, there is no single item in the Comp table which can be used as a relational link to the Layer table. This problem can be overcome by defining a new item in both the comp and layer tables which is a concatenation of muid and seqnum. This done in the following way:
In Arc go to tables:
Arc: tables
Select a table to work on:
Enter Command: sel comp
5579 Records selected
Enter Command: items [lists the items in the comp table]
COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME INDEXED?
1 STSSAID 5 5 C - -
6 MUID 7 7 C - -
13 SEQNUM 2 2 I - -
15 MUSYM 5 5 C - -
20 COMPNAME 30 30 C - -
50 S5ID 6 6 C - -
56 COMPPCT 3 3 I - -
59 SLOPEL 2 2 I - -
61 SLOPEH 2 2 I - -
63 SURFTEX 8 8 C - -
71 OTHERPH 40 40 C - -
111 COMPKIND 1 1 C - -
112 COMPACRE 6 6 I - -
118 CLASCODE 20 20 C - -
138 ANFLOOD 5 5 C - -
143 ANFLODUR 12 12 C - -
155 ANFLOBEG 3 3 C - -
158 ANFLOEND 3 3 C - -
161 GSFLOOD 5 5 C - -
166 GSFLODUR 12 12 C - -
178 GSFLOBEG 3 3 C - -
Continue? nEnter Command: redefine [indicates the creation of a new item from existing ones]
Enter Starting Column: 6 [this begins the new item at column 6 of the comp table, at the beginning of the MUID field]
Item Name: museqnum [a temporary name]
Item width: 9 [this takes in the 7 characters of MUID and the two numbers of SEQNUM treated as character text]
Item output width: 9 [display width]
Item type: c [character display]
Enter starting column: [just hit return to end the dialog on redefine]
Enter Command: sel [close comp]
File Comp is now closed
Enter Command: additem comp mucomp 9 9 c seqnum
This adds a new item to the comp table called mucomp located after the item seqnum in the table.
Enter Command: sel comp [select the comp table again]
5579 Records selected
Enter Command: move museqnum to mucomp
This puts the values defined earlier in the temporary item museq into the new item mucomp. The new item can be viewed by using:
Enter command: list muid seqnum mucomp
Record muid seqnum mucomp
1 TXW 1 TXW 1
2 TX001 1 TX001 1
3 TX001 2 TX001 2
4 TX001 3 TX001 3
5 TX001 4 TX001 4
6 TX002 1 TX002 1
7 TX002 2 TX002 2
8 TX002 3 TX002 3
9 TX002 4 TX002 4
10 TX002 5 TX002 5
11 TX002 6 TX002 6
12 TX003 1 TX003 1
13 TX003 2 TX003 2
14 TX003 3 TX003 3
15 TX003 4 TX003 4
16 TX003 5 TX003 5
17 TX003 6 TX003 6
18 TX003 7 TX003 7
19 TX003 8 TX003 8
20 TX003 9 TX003 9
21 TX003 10 TX003 10
22 TX003 11 TX003 11
Enter Command: sel layer
and repeat the above operation on the layer table to add mucomp to the layers.
Here is the dialog that accomplishes the addition of the new item to the layer table:
Enter Command: items
COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME INDEXED?
1 STSSAID 5 5 C - -
6 MUID 7 7 C - -
13 SEQNUM 2 2 I - -
15 S5ID 6 6 C - -
21 LAYERNUM 1 1 I - -
22 LAYERID 2 2 I - -
24 LAYDEPL 2 2 I - -
26 LAYDEPH 2 2 I - -
Continue? n
Enter Command: redefine
Enter starting column: 6
Item name: museqnum
Item width: 9
Item output width: 9
Item type: c
Enter starting column:
Enter Command: sel
File LAYER is now closed.
Enter Command: additem layer mucomp 9 9 c seqnum
Enter Command: sel layer
17102 Records Selected.
Enter Command: move museqnum to mucomp
Enter Command: list muid seqnum mucomp
Record muid seqnum mucomp
1 TX001 1 TX001 1
2 TX001 1 TX001 1
3 TX001 1 TX001 1
4 TX001 1 TX001 1
5 TX001 2 TX001 2
6 TX001 2 TX001 2
7 TX001 2 TX001 2
8 TX001 3 TX001 3
9 TX001 3 TX001 3
10 TX001 3 TX001 3
11 TX001 4 TX001 4
12 TX001 4 TX001 4
13 TX001 4 TX001 4
14 TX002 1 TX002 1
15 TX002 1 TX002 1
16 TX002 1 TX002 1
17 TX002 2 TX002 2
18 TX002 2 TX002 2
19 TX002 2 TX002 2
20 TX002 3 TX002 3
21 TX002 3 TX002 3
22 TX002 3 TX002 3
Continue? n
Then you can relate the two mucomp items between the comp and layer table and
perform vertical integration of soil properties across layers.
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