Formatting Land Cover Data for Land Change Modeler

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Clark Labs Tech Support Team
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Data preparation for Land Change Modeler is very format specific. Users that are currently using IDRISI Andes and Taiga will find this discussion most helpful, while users with later versions have the benefit of the Harmonize tab in LCM. The Harmonize tab resolves issues related to the input earlier and later land cover maps specified in the LCM Project Parameters panel in Land Change Modeler. Land Change Modeler requires that the input land cover maps meet specific requirements in terms of their spatial characteristics, backgrounds, and legend categories. 

The formatting requirements for the input land cover maps include:

  1. Consistent spatial extents
  2. Consistent references systems
  3. Consistent pixel resolution
  4. Identical legend categories
  5. A background value of zero
  6. Identical background area

How to create legends in IDRISI to comply with the requirement of the Land Change Modeler:

To create the legends, please go to the TerrSet Explorer pane and select the Files tab. You should now see all of the files either in your Working Folder or in a Resource Folder. Highlight one of the land cover maps for which you wish to update the legend. Once highlighted, scroll through the Metadata below until you come to a row titled “Categories”. Click in the adjacent cell and a pick list button (…) will appear. Click the pick list button – this is where you will fill out your legend. Make sure to include a name for every legend category, and do not skip any categories. The code is the value as it appears in your map. For example, if you have four categories (1, 2, 3, 4) representing agriculture, forest, built, and water, the table should be filled out as follows:        

Code

Category

1

Agriculture

2

Forest

3

Built

4

Water

Press OK and then click the save icon in the lower left hand corner of the Idrisi Explorer to save your edits. To update a second map with the same legend, highlight the file and again navigate to the Categories window. This time, in the lower left-hand corner of the window there will be a button that reads, “Copy from…”.  Click this button and select the land cover map that you just updated. This will automatically fill in the legend categories for you. Save your edits. You should now be able to input the map files into LCM.

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43 Comments

Date Votes
  • 2
    Avatar
    Chitrini Mozumder

    Thanks for the useful information. But, what about the driving factor layers. For example, I have a distance to roads layer, do I have to make categories for this layer also. Again, if I have a soil layer with 5 classes as driving factor, should I divide the raster to 5 different rasters or just categorizing the legend will do? Thanks in advance for your help.

  • 1
    Avatar
    Liz Goldman

    I also have a similar question as Chitrini. Should soil types be assigned a unique value, similar to how land classes are assigned values?

    Land cover maps should have a background value of 0, but what about driver variables? Sometimes 0 is significant in a driver variable, such a slope. What do you recommend for background, nodata values for driver variables?

    Also, to help with Chitrini's first question (distance to roads) I have been using the values 0-x, with 0 being the feature and x being the farthest distance from the feature in meters. No need to use categorical values for distance drivers.

     

  • 0
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    lavinia perumal

    Okay I have checked the extent and number of rows and columns for land cover and driver variables, they are the same so im not sure whats the issue?

  • 0
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    Wakiibi Ceaser Kisa

    Hello

     

    I received this error in Terrset and couldn't create a change map due to Attribute values documentation file in D:\\00.Thesis\Terrset\R.Namatala\idrtmp_lul not found.

  • 0
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    Akanksha Balha

    Hello Iavinia, 

    what is the error?

     

  • 0
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    soma

    At the time I run LCM, after doing harmonize. Then I click continue, the program runs well up to bring up the graph data change analisys but when I will running "create maps" on Tab "change maps" error appears in the form of "attribute value documentation file: \ D ... \ id not found"
    Can I get suggestions regarding the issue. Is there a process error?

  • 0
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    JISHA JOHN

    I would like to find out the land cover change in my study area during the period of 2001 - 2010. I classified the land use in the study area by using Erdas imagine. The obtained result shows that the urban coverage in the area during 2010 is higher than 2001. But the net change analysis results show that the net change in urban area between 2001 - 2010 as a negative value ( quantification). Can I resolve that problem? 

  • 0
    Avatar
    Eskinder Sintayheu

    Hello,

    I would like to generate Markov transition area files and probability matrix in IDRISI with 8 LULC classes. All the land cover data (inputs) have LULC 8 classes. However, the model stretched them into 15 classes which is not real in the ground? What could be the possible reasons for having 15 classes and how can be resolved? Thanks.

  • 0
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    Clark Labs

    HI, At what step did the land cover maps change from 8 to 15 classes? 

    James

  • 0
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    Clément Hanser

    Hello,

    I tried to use the land change modeler comparing 2 raster images of landcover. When I try to process it, it tells me  "background areas do not match or background code is not 0", and asks me if I want to resolve it. I click yes, but then in the harmonize background window, category value(s) to assign to 0 for both images are already set on 0...

    So I click Run and this error message comes up:

    Attribute values documentation file D:\C.H\Memoire\Final\TerrSet\idrtmp_bool.ADC not found. 

    I have no idea what this message means, can you please help me? 

    Thanks

  • 0
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    Astrid Palupi

    hi..i tried to validate LU 2015 from (2003 and 2009 data), but the result was "error 0" how to fix it ? 

  • 0
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    Deepakshi

    hi.

    In order to run LCM change analysis step , what type of file format is used to add the road layer and elevation model? i have converted my road shapefile to vector file and then vector file to raster file, after creating road blank file. A map is created which i have added as a input in 'road layer' but it says map must contain legends..what type of legend i should add( e.g names of roads or what) and how?

  • 0
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    kyihtut win

    It is all about conventional warfare for 3 S technology( GPS,GIS ,RS).

    "Congratulation for All Geographers around the World GIS2018"....

    win

    kyihtut win(mr)

    Geographer from Myanmar.

    IDRISI Taiga16.05 Stand Alone User since 2011Dec13.

    khw13256@gmail.com

     

  • 0
    Avatar
    t.enkhamgalan_042731

    What should I do?  Help me!!!!  t.enkhamgalan_042731@yahoo.com

    (error. Unexpected error condition encountered. Please check the integrity of the operation performed, the data files used and the amount od disk space available.)

    Edited by t.enkhamgalan_042731
  • 0
    Avatar
    Kimaramoodley650

  • 0
    Avatar
    Kimaramoodley650

    Hi guys currently experiencing this problem, please help

  • 0
    Avatar
    Kimaramoodley650

    how do I solve 

    1. Maps contain negative category code

    2. both land-use maps must contain identical legends

  • 0
    Avatar
    Paulina Contreras

    Hi!

    I have an issue with LCM, when I want to enter my land uses in the process, it looks this messages: 

    And read before, that IDRISI reads reference system like a plane, and i have that in  metadata. I don't know how can i fix it. Someone knows?

    Thanks!

  • 0
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    Rajib Sarkar

    How to solve issues like " Error: the basis road layers does not have any legend"?

  • 0
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    Md. Sumon Ali

    Please tell me someone how can i solve this error messege? How can i create idrtmp_bool.ADC file ? 

  • 0
    Avatar
    Md. Sumon Ali

    Thanks Clark Labs for giving the solution of my problem.

  • 0
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    Md. Sumon Ali

    Clark Labs Clark Labs Tech Support Team

    This is my problem. Whats going on i don't understand. In previous reply you said to reclassify and harmonize them, I did that, even 15 value assigned class have ignored by assigned with zero value. Then both of raster class are same and there background valu has inputed zero. But still it shows idrtmp_bool.ADC file didn't found.

  • 0
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    Roshan Sharma

    Why do I get a message that my spatial reference system is incompatible with IDRISI reference system. My land cover images have WGS_1984_UTM_Zone_49S. How do I fix this problem? 

  • 0
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    o2

    This is only for land cover maps. 

  • 0
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    Liz Goldman

    Yes, I haven't been able to find a similar article for driver variables though. I am hoping to learn more about formatting for driver variables and have my questions answered. If you know of a resource for specific formatting guidelines for drivers please post a link!

  • 0
    Avatar
    o2

    The format for Driver variables: 

    1. Consistent spatial extents (the same area, mask)
    2. Consistent references systems (e.g. wgs89)
    3. Consistent pixel resolution (e.g. 200 meters). 
  • 0
    Avatar
    Liz Goldman

    Thanks! And what about background values? Sometimes 0 can be significant in driver variables (like slope or elevation). Will using 0 for a background value affect the results?

    Also, how do you handle variables like soil or other non-distance from based driver variables? Do you just use a unique value for each soil type?

  • 0
    Avatar
    o2

    You must not use zero as null-value (or background) because there are a lot factors related to proximity. I recommend you use as null-data = -9999. Really, this decision depends of your data. You should specify this value. Null-value or background value must be the same in all factors. Finally,you should transform the categoric factors by using "Variable Transformation Utility / Variable Transformation Utility - Evidence likelihood transformation"

     

    Edited by o2
  • 0
    Avatar
    Clark Labs

    If you have land cover maps with background, you do not have to be concerned with the background value of the driver variables for those areas the coincide with the land cover background. When training during the Transition Potential stage, samples will be take from area of valid land cover only, not from background areas. 

    Per Oli's comment, you will find in the tutorial a working example for creating evidence likelihoods for your soil data. 

    James

  • 0
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    Asubar2002

    hello everyone.

    Using a Landsat scene to carry out supervised classification.

    The background on Landsat scene appears as a feature (class) in my classification.

    Initially has a value of zero but still appears

    Any idea how to solve this?

     

    Thanks

     

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