Best way to add Attribute data to a shape file

Question

Hei GISers!!

Thanks for your help with my previous question. My apology if this may be too simple a question for this site, but I am still learning the various aspects of GIS.

Now that I can display the shapefile in openlayers, I need to add some attribute data. I can open the dbf file in excel but there is no save as option in excel to the updated file as a dbf.

So my question is, what is the best way (or software to use) to add attribute data to my shape file?

Thanks Chris

Answer 1

Using QGis you can edit your shapefile adding new columns and values. Just open the shapefile, go to Properties>Attributes and add new columns.

Answer 2

Use R with the foreign package to modify the DBF file:

library(foreign)
dbfdata <- read.dbf("file.dbf", as.is = TRUE)
## add new attribute data (just the numbers 1 to the number of objects)
dbfdata$new.att <- 1:nrow(shp)

## overwrite the file with this new copy
write.dbf(dbfdata, "file.dbf")

Or read the geometry and attribute data with the rgdal package (so you could modify the relationships as well and create a completely new shapefile):

library(rgdal)
## read "/path/to/files/filename.shp"
shp <- readOGR("/path/to/files/", "filename")  

## add new attribute data (just the numbers 1 to the number of objects)
shp$new.att <- 1:nrow(shp)

## write out to a new shapefile
writeOGR(shp, "/path/to/files/", "filename2")  

Answer 3

Not sure if it's the best way, but I've merged several shapefiles using MS Access. I needed to left join some data from other shapefile and it worked quite well. Also it was quick. However I guess not everyone has this software

Answer 4

I would not recommend using OpenOffice - or a similar application - at all! Darren Cope commenting an answer to the question "DBF creation and manipulation without excel 2003" said:

it's that shapefiles get quite upset if you go and edit the .dbf in an 'outside' program

Answer 5

uDig has a nice tool called reshape, through which you can for example add attributes to a table: http://tinyurl.com/4f8xmq9

But you can also do that on a more advanced way, generating them through functions. For example you could convert geometries: http://tinyurl.com/48h5n8j

Supported functions are those of the common query language: http://tinyurl.com/4ezpmbm

Answer 6

Open Office Calc allows you to read and write dbf files. But Lcasagrande's solution using QGIS should be safer.

Answer 7

My apology if this may be too simple a question for this site

That is certainly not the case. I've often wondered myself what is the best way to edit dbf files. I usually use R (check mdsomners answer), but I would not recommend learning that if that is the only thing you want to do. I think the best approach would be using a GIS program, to create the fields, and then try editing them using openoffice.

More importantly, you should think whether you need to edit all the fields the attribute table directly, or if you can join other tables to it. The latter can be done in most GIS programs, eg SAGA GIS

http://www.saga-gis.org/saga_modules_doc/shapes_tools/index.html

Answer 8

as andy pointed out in the link DARIAPRA refered you to, there is a Excel 2007 ADD-IN you might find useful - It allows you to save in the dbf format.you can find it on this website:

http://savedbf.blogspot.com/

(As I have Excel 2003, I've never tried it, but I heard it was useful.

As for DBF manipulation outside ArcGIS - I've done it a few times. Sometimes it works, sometimes it doesn't. My two cents: If you can avoid the outside manipulation, avoid it. If you're dealing with a non-english language avoid it altogether - It tends to get all fumbled up when editing outside of ArcGIS).

Answer 9

Alternatively:

1. open the dbf in MS Excel 2007/10
2. Make your changes (adding columns, populating data etc) and save as xls/xlsx
3. Navigate to xls/xlsx location in ArcCatalog, right-click the worksheet and choose Export > To dBase (single)
4. Rename the output dbf file as required

Answer 10

Using QGIS is nice, and provides a solid interface for interacting with the DBF, but if you need to do something programmatically or just want tools to inspect shapefiles, I thought I'd mention a few other tools: I often use the basic features of shapelib for examining DBF files: it can add, create and modify both geometries and attributes, I often use dbfdump myshape.dbf to get a quick overview of the attribute values.

Another option if you're interested in programmatic control of a DBF is dbfpy, a python library (an an alternative to the nice foreign library mdsummer mentions). An example script for adding a column:

import dbfpy

db = dbf.Dbf("myshape.dbf", new=False)
# add a new character field named 'myfield'
db.addField(("myfield", "C", 15))

db.close()