Troubles Joining in Arcview
So I'm having trouble joining my shapefile to my group survey table. I wasable to get it to join to the sanborn survey table but I can't figure this oneout. It seems like they join with no problem but when I try to open theattributes table it says "Error exporting data. The Microsoft Jet databaseengine cannot find the input table or query 'GDB_ObjectClasses'. Make sure itexists and that its name is spelled correctly." Do you guys have anysuggestions as to what's going on?
posted by John Hinchman @ 8:36 AM
1 Comments:
Joining tables together in any table driven software can often be a difficult process. If the data which are being joined are not exactly the same they WILL NOT join. This being said it is quite possible that they look exactly the same. You've opened both tables beside each other and have found that the Numbers, Letters, and Symbols are EXACTLY the same. No Capitals where there are supposed to be samlls no letter O where there is supposed to be a number 0. In other words they are identical. Recognizing of course that if you chose to join by a number, and one of the columns is set as a numeric value and the other is set as string value then they too will not join. In this case the data type is not consistent. Numbers and Strings WILL NOT join.
At this point you are at the end of your string and are considering a short walk off a long pier. There is hope if the uniquie value you created has compnents in it that can be isolated and used as a joining option. Consider the fact that many people have chosen to use a Unique ID which works something like the following: 1400N-1, 1400N-2, 1400N-3 etc. etc. etc. If this is in fact the way the numbers were set then you may find that separating those values into simpler elements may be to your advantage. If you look at this system you will see that the full number is not truely unique in your table. If you consider that there are two parts to the value, then the first part of the value is the number of the block and the second part is the value for the structure. Since at this point you are not using any other block, then the first part of the ID is not really the unique element. In other words the "1400N" simply repeats through all of the ID's showing that it is really the second part of the ID that is unique. With the understanding that a number is the easiet component for the tables to use as a join consider breaking apart your unique ID's so that you are joining using only the building number and not the block number as well.To do this you will need to think about ways that this can be accomplished. Remember that it doesn't matter how you do it as long as you don't mix up the data.
Consider using EXCEL's "text to column" option which uses a delimiter to separate pieces of a whole by using repeat characters. Export your table from ACCESS to EXCEL and copy the column which contains the unique ID so that there are now two of them. Add a few blank columns to the right of the new column you just copied and use the "text to column" option. In most cases you will be able to use the hyphen as the delimiter. If the Number is 1400N-23, then the result will be two columns with one containing the 1400N and the other containing the 23. Once you've done this you will need to figure out a way to divide the table is ArcGIS to accomplish the same thing. Export a copy of the table from ArcGIS and open it in EXCEL. In this case you will do the exact same thing creating a duplicate of the unique ID column and then dividing it into two columns. Once you have this done you can actually remove all of the columns from this table which are not important (hint: the only important ones are the original unique ID as well as the column containing the number 23). Close this table making sure that you save it as a DBF and add it back to ArcGIS using the join option to link it to the original table. The join that you will be making will use the original Unique ID column and it WILL worksince they are the same column originally. Once you have this join created you will remake the shapefile so that these joins become permenent. With the firsty joins now set you will see that the new shapefile attribute table has the column of original unique id's as well as a cloumn of new ids which were just the numbers and not the block id. Now you can bring in the access table which you changed in EXCEL to cantain this new number column. Now join the Access tabla and the ArcGIS table using these common number columns instead of the original unique ID's and you should have success.....Creativity is the mother of invention.
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