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Trying to load the tfw when opening a tif file

Question asked by twiggerich on Mar 7, 2017
Latest reply on Jul 4, 2017 by twiggerich

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Hello ,

I am trying to load a tif file (map000.tif) and also the correspondig tfw file (map000.tfw).

What he actually does is, he loads the given map (map000.tif) and shows it. But I don't think that he loaded the tfw file correctly. (So loading two rasters they will be shown at the same position.)

There is no SpatialReference which I could set?

I tried to set the set SpatialReference of the Map (m_map) but it then shows nothing.

m_mapView = new MapGraphicsView( this );


QString dataPath = "<Path>\\map000.tif";

Esri::ArcGISRuntime::Raster * raster = new Esri::ArcGISRuntime::Raster( dataPath, this );

Esri::ArcGISRuntime::RasterLayer* rasterLayer = new Esri::ArcGISRuntime::RasterLayer( raster, this );


std::cout << "SpatialRefernce: " << rasterLayer->spatialReference().wkid() << std::endl;

mp_basemap = new Esri::ArcGISRuntime::Basemap( rasterLayer, this );

m_map = new Esri::ArcGISRuntime::Map( mp_basemap, this );

m_mapView->setMap( m_map );

What do I wrong?

A long time ago I had a similar question concering the SDK 10.2.3.

How to load the .tfw file when opening a .tif file?

With kind regards

Torben

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20 Replies

LSmallwood-esristaff Mar 8, 2017 4:25 AM
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Hi Torben,

I think your code to load the RasterLayer looks correct - however, the spatialReference for this layer will not be set until it has been loaded. In your example, this happens when the map is added to the mapView, triggering a load for all of the dependant objects. You can read more about the details of our Loadable Pattern on this Guide Topic: Loadable pattern for asynchronous resources—ArcGIS Runtime SDK for Qt | ArcGIS for Developers

If you want to log the spatialReference of your layer once it has been loaded, you can add a connection to the "doneLoading" signal of this type - for example, replace this line:

std::cout << "SpatialRefernce: " << rasterLayer->spatialReference().wkid() << std::endl;

with:
```
connect(rasterLayer, &RasterLayer::doneLoading, this, [rasterLayer](Error loadError)  {
```
```
   if (rasterLayer->loadStatus() == LoadStatus::Loaded)
      qDebug() << "SpatialRefernce: " << rasterLayer->spatialReference().wkid();
```
});

I hope that helps,

Luke
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- twiggerich @ LSmallwood-esristaff on Mar 8, 2017 5:14 AM
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  Hi Luke,
  
  thanks for your quick response!
  
  I replaced the code and now I get the following line:
  SpatialReference: 0
  
  So I think the problem is that I get a SpatialReference of 0. How can I change this?
  
  With kind regards
  Torben
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  - Dan_Patterson @ twiggerich on Mar 8, 2017 5:38 AM
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    within any of the Arc* suite of software a *.tifw doesn't not contain the spatial reference reference (ie ESPG code etc), it just contains information on how to translate the coordinate space. For more information see this link
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    - twiggerich @ Dan_Patterson on Mar 9, 2017 12:59 AM
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      Hi,
      
      ah ok that is good to know, that there is no spatial reference!
      
      So my problem is than if I set the SpatialReference to load wgs84 and then load the given tif.
      To see the image we need to set the viewpoint correctly. What is done I hope...
      But I can't see anything...
      
      m_mapView = new MapGraphicsView(this);
      m_map = new Esri::ArcGISRuntime::Map( Esri::ArcGISRuntime::SpatialReference::wgs84(), this );
      QString dataPath = "<Path>\\map000.tif";
      Esri::ArcGISRuntime::Raster * raster = new Esri::ArcGISRuntime::Raster( dataPath, this );
      Esri::ArcGISRuntime::RasterLayer* rasterLayer = new Esri::ArcGISRuntime::RasterLayer( raster, this );
      mp_basemap = new Esri::ArcGISRuntime::Basemap( rasterLayer, this );
      m_map->setBasemap( mp_basemap );
      m_mapView->setMap( m_map );
      Esri::ArcGISRuntime::Envelope envelope( 5.520, 52.270, 5.530, 52.280, Esri::ArcGISRuntime::SpatialReference::wgs84() );
      m_mapView->setViewpointGeometry( envelope );
      
      And the map000.tfw file has the following format:
      1,07020139694214E-05
      0
      0
      -6,54231601356988E-06
      5,52524901390075
      52,2788632621671
      
      With kind regards
      Torben
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      - LSmallwood-esristaff @ twiggerich on Mar 9, 2017 3:03 AM
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        Hi Torben,
        
        Can you confirm that the raster you have is actually in wgs84? Rather than manually creating the envelope from the data in the .tfw file you could try setting the map view to the layers extent when it is loaded. Something like:
        
        connect(rasterLayer, &RasterLayer::doneLoading, this, [this, rasterLayer](Error loadError)
        {
              if (loadError.isEmpty())
                    m_mapView->setViewpointGeometry(rasterLayer->fullExtent());
        });
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        twiggerich @ LSmallwood-esristaff on Mar 9, 2017 3:22 AM
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        Hey,
        
        so runinng the old version (10.2.3) it was ok to load it with a setting of SpatialReference 4326. Which is in my opinion the same as wgs84?
        
        I changed my code to your above statement.
        
        connect(rasterLayer, &RasterLayer::doneLoading, this, [this, rasterLayer](Error loadError)
        {
             if (loadError.isEmpty())
             {
                  m_mapView->setViewpointGeometry(rasterLayer->fullExtent());
                  std::cout << "Set map view: " << rasterLayer->fullExtent().xMin() << ", " << rasterLayer->fullExtent().yMin() << " -> " << rasterLayer->fullExtent().xMax() << ", " << rasterLayer->fullExtent().yMax() << std::endl;
             }
        });
        
        But he gives me the following output:
        Set map view: -nan(ind), -nan(ind) -> -nan(ind), -nan(ind)
        
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        LSmallwood-esristaff @ twiggerich on Mar 9, 2017 3:53 AM
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        Hi Torben,
        
        I've tried with a few raster data-sets here and they are all working correctly. Would it be possible for you to share the data in anyway?
        
        Another thing you could try is to simply load a map with a basemap (not your raster) at the envelope position you use above to confirm that is correct. When I do that, I see an area near Almere in the Netherlands - is that correct? The code I am using is:
        Basemap* basemap = Basemap::imageryWithLabels(this);
        Map* map = new Esri::ArcGISRuntime::Map( /*Esri::ArcGISRuntime::SpatialReference::wgs84(),*/ this );
        
        map->setBasemap( basemap );
        m_mapView->setMap(map);
        Esri::ArcGISRuntime::Envelope envelope( 5.520, 52.270, 5.530, 52.280, Esri::ArcGISRuntime::SpatialReference::wgs84() );
        m_mapView->setViewpointGeometry( envelope );
        Notice that I have commented out the Spatial Reference in the constructor of the Map: when I uncomment this, the position is not loaded correctly (I will investigate that further).
        
        If this loads at your desired location, you could try your raster code but creating the Map with no Spatial Reference?
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        twiggerich @ LSmallwood-esristaff on Mar 9, 2017 4:25 AM
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        Hi Luke,
        
        I'm not sure what I should share with you? So I have just an Image (tif) and the corresponding tfw file. The tfw file I have already posted. Do you want the image?
        
        The problem is that when I open the tif, without setting the map, it will display all loaded tifs at the same position. So they are all overlapped at the same position. It seems that in this case even the tfw file is not loaded...
        Because of this I think I have to use the following line:
        Map* map = new Esri::ArcGISRuntime::Map( Esri::ArcGISRuntime::SpatialReference::wgs84(), this );
        Else all loaded tif are overlapping...
        But then I don't see anything...
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        twiggerich @ twiggerich on Mar 9, 2017 4:28 AM
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        Ah sorry, yes it is the correct position
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        LSmallwood-esristaff @ twiggerich on Mar 9, 2017 4:38 AM
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        Hi Torben,
        
        If you are able to send me the image I can try to load it to see if it works for me.
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        twiggerich @ LSmallwood-esristaff on Mar 9, 2017 5:10 AM
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        Hi Luke
        
        I tried to upload the data here, but it is not shown...
        I tried to send it to you, but I don't have the rights to do that...
        
        So here it is...
        https://files.fm/u/9ya8m6xd
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        LSmallwood-esristaff @ twiggerich on Mar 9, 2017 7:59 AM
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        Hi Torben - thank you for sending me through the data.
        
        I think that the problem is that your data does not include information on the coordinate system: when you load it in a Map with no reference it ends up being displayed in Spatial Reference "0" (which as you say is not valid). In the Runtime SDK we do not support on-the-fly projection of raster data so when you try and load it into a map with a defined system (e.g. WGS84) it cannot be displayed.
        
        For tiff files such as this one, there are a number of ways in which coordinate and projection information can be supplied. The .tfw file provides the coordinates you use in your envelope - for the coordinate system information I believe this is usually either encoded into the header of the .tif file itself or provided in a separate .aux file. Unfortunately I do not know of a straight-forward way to apply either of these approaches. If you have access to ArcMap you can use a tool such as "Define Projection" to specify the system for your file - I tried that and was able to successfully load your raster draped over another basemap in the correct location.
        
        I hope that is helpful - I will do a little bit more research into the problem and let you know if I find a work-around.
        
        Thanks,
        
        Luke
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        twiggerich @ LSmallwood-esristaff on Mar 9, 2017 11:46 PM
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        Hi Luke,
        
        it is good to hear that you can't load the image too.
        With the SDK 10.2.3 I was able to load and display the image correctly. Does this change to the current release?
        
        The way to use ArcMap is no option for us.
        
        With kind regards
        Torben
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LDanzinger-esristaff Mar 10, 2017 4:03 PM
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Torben,

This tiff file doesn't have a projection defined. I can see this by opening it in ArcCatalog (see attached image). If there is no projection defined, it will likely just display at 0,0 (aka null island), and all other data that doesn't have anything defined will display there as well. You will want to make sure the data has a projection defined before consuming in ArcGIS Runtime - Defining or modifying a raster's coordinate system—Help | ArcGIS for Desktop

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- twiggerich @ LDanzinger-esristaff on Mar 13, 2017 12:55 AM
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  Hi Lucas,
  
  my current problem is that with the Runtime 10.2.3 I was able to load these images and display them at the correct position. Is this not possible with the Version 100?
  
  Can I define it somewho in the code. Maybe that he should ever use one SpatialReference if there is no one defined?
  
  Our customers will not have access to such a big tool (AcrGIS for Desktop).
  But they should be able to load their images correctly.
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  - LDanzinger-esristaff @ twiggerich on Mar 14, 2017 9:02 AM
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    I'm not sure how this worked before. It seems like the behavior that we are seeing now is expected. Can you post an example project from 10.2.3, along with sample data so we can take a look?
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    - twiggerich @ LDanzinger-esristaff on Mar 24, 2017 6:32 AM
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      Hi Lucas,
      
      sorry for my late reply...
      
      Here is the example project:
      https://files.fm/u/p57zgqfb#_
      
      There are two images loaded and displayed correctly.
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      - twiggerich @ twiggerich on Jul 3, 2017 6:53 AM
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        Hi Lucas,
        
        did you have a try on this?
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        LDanzinger-esristaff @ twiggerich on Jul 3, 2017 1:32 PM
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        Sorry Tobern, I completely missed this. I'll be pretty tied up the next 2 weeks with the User Conference (and prep for it). I will try and take a look after.
        
        - Luke
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        twiggerich @ LDanzinger-esristaff on Jul 4, 2017 5:59 AM
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        Thx, for having a look on this
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