+5
Hi,
I am making landuse change of 2 times but the data vector is so big.
So I want to convert raster and make matrix landuse change in FME. Firstly, I will convert vector to raster and then find a intersect raster function.
But I don't find the function to intersect raster. With vector, I used AreaOnAreaOverlayer function.
Could you show me the function to intersect raster?
Thank you
+2
Hi,
Since, you want only intersections by using AreaOnAreaOverlayer then use BoundingBoxReplacer to make raster to vector on-the-fly.
At any point you can take raster by using parallel connections.
Pratap
+17
Hi @hoa_le, you can use the RasterExtentsCoercer (Extents Type: Raster Extents) or the BoundingBoxReplacer to convert the rasters to rectangle polygons which represent their extents. You can then use the AreaOnAreaOverlayer and the Tester to get the overlapping area, and clip the original rasters by the area.
+13
If you want to work entirely in Raster, you can combine rasters using the RasterExpressionEvaluator. We recently explored this type of approach on a webinar -- check the recording at https://www.safe.com/webinars/choosing-the-right-transformer-for-your-data-challenge/ and in particular, jump to the "Rad Radar" bookmark in the video -- it is very similar to what you want to do.
+5
Hi @hoa_le, you can use the RasterExtentsCoercer (Extents Type: Raster Extents) or the BoundingBoxReplacer to convert the rasters to rectangle polygons which represent their extents. You can then use the AreaOnAreaOverlayer and the Tester to get the overlapping area, and clip the original rasters by the area.
1. Convert polygon to raster
2. Intersect 2 rasters to decrease memory because my data's so big
Normal, I intersect 2 vectors use AreaOnAreaOverlayer function. Now I want to use raster to intersect.
Could you show me how to the way to intersect raster?
Thank you
+17
Hi @hoa_le, you can use the RasterExtentsCoercer (Extents Type: Raster Extents) or the BoundingBoxReplacer to convert the rasters to rectangle polygons which represent their extents. You can then use the AreaOnAreaOverlayer and the Tester to get the overlapping area, and clip the original rasters by the area.
+5
If you want to work entirely in Raster, you can combine rasters using the RasterExpressionEvaluator. We recently explored this type of approach on a webinar -- check the recording at https://www.safe.com/webinars/choosing-the-right-transformer-for-your-data-challenge/ and in particular, jump to the "Rad Radar" bookmark in the video -- it is very similar to what you want to do.
In my case, I need 2 steps:
1. Convert 2 layers polygon to raster
2. Intersect 2 raster
Actually, I can do it in vector file. But my vector is so big. So I want to convert to raster to intersect, it's not heavy.
Could you tell me how is the way to do it?
Thank you
+5
Hi @hoa_le, you can use the RasterExtentsCoercer (Extents Type: Raster Extents) or the BoundingBoxReplacer to convert the rasters to rectangle polygons which represent their extents. You can then use the AreaOnAreaOverlayer and the Tester to get the overlapping area, and clip the original rasters by the area.
My target is here:
+17
Hi @hoa_le, you can use the RasterExtentsCoercer (Extents Type: Raster Extents) or the BoundingBoxReplacer to convert the rasters to rectangle polygons which represent their extents. You can then use the AreaOnAreaOverlayer and the Tester to get the overlapping area, and clip the original rasters by the area.
I assume that the two rasters have different extents and you need to get their "intersection" (i.e. overlapped part).
If my assumption was correct, there is no transformer to directly "intersect" two or more rasters, such as the AreaOnAreaOverlayer for polygon features. However, you can create extents (polygons) of the rasters, get intersected area of them with the AreaOnAreaOverlayer, and then clip the rasters by the intersected area with the Clipper. The result would be equivalent to the "intersection" (overlapped part) of the two rasters. Isn't it your desired result?
If the two rasters originally have the same extents, and you need just to calculate difference between them for each cell, consider using the RasterExpressionEvaluator (Mode: Two Rasters). Although I don't think it's "intersect" operation...
+5
Hi @hoa_le, you can use the RasterExtentsCoercer (Extents Type: Raster Extents) or the BoundingBoxReplacer to convert the rasters to rectangle polygons which represent their extents. You can then use the AreaOnAreaOverlayer and the Tester to get the overlapping area, and clip the original rasters by the area.
"Intersect" mean " AreaOnAreaOverlayer.
I attached demo data. But I got error when runing rasterExtentcoeroer.
I have 2 layer polygon 2010_test (Use field ldlr_2010) and 2015_test (use field ld_2015) to convert polygon to raster. But i got errors.
Could you tell me why?
raster.fmwt
+17
Hi @hoa_le, you can use the RasterExtentsCoercer (Extents Type: Raster Extents) or the BoundingBoxReplacer to convert the rasters to rectangle polygons which represent their extents. You can then use the AreaOnAreaOverlayer and the Tester to get the overlapping area, and clip the original rasters by the area.
What is your question - how to create raster from the polygons, how to intersect rasters, or both?
+5
Hi @hoa_le, you can use the RasterExtentsCoercer (Extents Type: Raster Extents) or the BoundingBoxReplacer to convert the rasters to rectangle polygons which represent their extents. You can then use the AreaOnAreaOverlayer and the Tester to get the overlapping area, and clip the original rasters by the area.
Hi @takashi,
My question is both. Step 1: creat raster from polygon, step 2: intersect raster
+17
You can use the 3DForcer and the NumericRasterizer to convert the polygons to rasters. However, you will have to determine these things at first to set the parameters in those transformers.
+17
You can use the 3DForcer and the NumericRasterizer to convert the polygons to rasters. However, you will have to determine these things at first to set the parameters in those transformers.
Please modify parameters (attribute to be used as cell value, cell spacing, background value, etc.) appropriately.
+5
You can use the 3DForcer and the NumericRasterizer to convert the polygons to rasters. However, you will have to determine these things at first to set the parameters in those transformers.
I made workflow the same in the bellow. But in RasterExpresstionEvaluator I don't use the parameters. I attached my workspace here:
lc.fmwt
+17
I made workflow the same in the bellow. But in RasterExpresstionEvaluator I don't use the parameters. I attached my workspace here:
lc.fmwt
Also, check carefully parameters in the NumericRasterizer. At least you have to set "fme_feature_type" to the Group By parameter.
If you project the polygons onto a specific coordinate system, the ground extents (xmin, ymin, xmax, xmax) should also be projected onto the same coordinate system.
+17
I made workflow the same in the bellow. But in RasterExpresstionEvaluator I don't use the parameters. I attached my workspace here:
lc.fmwt
+5
You can use the 3DForcer and the NumericRasterizer to convert the polygons to rasters. However, you will have to determine these things at first to set the parameters in those transformers.
Normally, with layer is less polygon. I use model the same the bellow.
Now I have to work with more over 80,000 records, so I see FME can't do this. I want to convert polygon to raster to descrease memory. So I want to convert to raster and make model look like here
poly.png
+17
Normally, with layer is less polygon. I use model the same the bellow.
Now I have to work with more over 80,000 records, so I see FME can't do this. I want to convert polygon to raster to descrease memory. So I want to convert to raster and make model look like here
poly.png
+5
+17
+13
+5
I don't know why when I read 2 layers in the .gdb and overlay them. I got error, reject it. But I read them and open inspector, it's view ok.
+5
+17
You can connect an Inspector to the Rejected port and run the workspace, in order to check what features would be rejected.
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