[GIS] Adding attribute field to raster layer in ArcGIS Desktop

arcgis-desktoparcmapattribute-table

I am from Vietnam and I am still a student. I have to study more about ArcGIS.

How do I add an attribute field in this case?

My project is using Landsat 8 picture to establish a drought map. After calculating LST and VHI I reclassify it and my teacher tells me to add an attribute field to it. I don't know how to do it, I watch people do it in YouTube but when they open the attribute table it is very different.

How can I add an attribute field to my project?

I have to calculate the area of each region too.

How do I do that?

Best Answer

You are working with a raster dataset, not a vector dataset. (https://gisgeography.com/spatial-data-types-vector-raster/)

This means that the attribute table is different -- it simply lists the number of cells which have each value. You can convert the dataset using Raster to Polygon (Conversion).

http://resources.arcgis.com/en/help/main/10.2/index.html#//001200000008000000

http://pro.arcgis.com/en/pro-app/tool-reference/conversion/raster-to-polygon.htm

Related Solutions

[GIS] Adding boolean yes/no field in ArcGIS Desktop

Many DBMSes including Oracle do not have a Boolean column type, so this may explain why there is no Boolean field type in ArcGIS either.

@Emily's suggestion of using a coded value attribute domain is a good one and I believe this is the ESRI-recommended best practice.

The only other suggestion I would have is to use a CHAR field of length 1, as this way you can use the slightly more descriptive "Y" or "N", or "T" or "F", rather than 1's or 0's, and, according to this article, in Oracle 1-character CHAR columns are actually more efficient than 1-digit NUMBER columns.

ArcGIS Attribute Field – How to Add Automated Values

Here is a code block for the Field Calculator that will do what you require.

Open the attribute table
Select all of the records that contain a NULL value in the desired field
Open up the Field Calculator and insert this code in the appropriate sections.

Accumulative and sequential calculations
Calculate a sequential ID or number based on an interval.

Expression:
autoIncrement()

Expression Type:
PYTHON_9.3

Code Block:
rec=0
def autoIncrement():
 global rec
 pStart = 1 #adjust start value, if req'd 
 pInterval = 1 #adjust interval value, if req'd
 if (rec == 0): 
  rec = pStart 
 else: 
  rec = rec + pInterval 
 return rec

This code sequence is taken from the ArcGIS 10.0 Desktop Help: Calculate Field Examples

I would highly recommend that you browse through the help documentation in that file and in the other help sections for ArcGIS, as there are many useful examples and code samples to pull from.

Enter the code above, into the Field Calculator as shown in the screen shot below: You would enter the code into the sections as detailed below:

Choose Python as the Parser
Pre-Logic Script Code: Enter code listed under Code Block
Under the field name, in this case, RD20FULL =: Enter code listed under Expression
Press OK

Example Field Calculator Code Entry

Best Answer

Related Solutions

[GIS] Adding boolean yes/no field in ArcGIS Desktop

ArcGIS Attribute Field – How to Add Automated Values

Related Question