Latest Contributions by DitlevReventlow

Thank you for all your answers. I interprete it as if I set the fixed scale to 1:200 and just print directly from Arcmap layout view (in A4), then 1cm on the printed map should be equal to 200 cm. I have just tried to do this, and it indeed seems to work.   ... View more

I think i printed it directly, but I am not completely sure. Which difference does it make whether you export or not? ... View more

I thought it was very strange that I didn't get the right result when i did nearest neightbour resampling but now I have the solution to the mystery. It does indeed use nearest, but not in the same way as "resample". Even though the processing extent is entirely the same and I have used snap raster it doesn't perform the operation in the same way in the two case. Combine selects the pixel above the pixel selected "resample" with nearest neighbour. Furthermore, while resample gives you the precise number, combine rounds down even though it is not correct to do so. This means if the nearest pixel is 17,9, then the new value will be 17. Very strange indeed. Thank you very much for your help Gabriel in the clarification of this! ... View more

And if it is possible that combine uses another resampling/interpolation method that is not part of the 4 options in the "resample" tool. ... View more

Thank you for this Dan. I believe I understand the general consequences of increasing or decreasing cell size through resampling. What I am unsure about is which interpolation/resampling method that "combine" uses? I have tested all the resampling method, except majority, and none of them gave the same results as combine. And this is even though I have adjusted the processing extent and the snap raster that that they fit. The reason why I havent tested majority is because there is not drawn any raster when I resample with majority. So I cannot check if the pixel values are the same as in the combined dataset. So what I am unsure about about is why the majority resampling method does not work, and if there is anywhere that I can check how combine resamples? I know it would be better to do it all over again (resample and then combine) but I dont have time to do this. I just need to know what happened (how information exactly was lost). ... View more

Thank you Dan. The thing is that I have already done it and there is no time to redo it, even though this would obvious be the best. I know it should have been the bigger raster that should have been resampled to the cell size of the smaller raster. Therefore, I just need to be aware of the consequences of the way that I have used combine (not using the "resample" tool, but having "combine" do the resampling process using the bigger cell size as output raster"). The importance is what combine has done in this process. Is there really no way to figure this out? ... View more

Great, thank you Dan and Steve. I tried all the different resampling method, except form majority, and none of them created the same number. The reason why I havent tested the majority method is because when I do the resampling with majority there is no output raster afterwards. I have tried it several times and each time the same. How can this be that majority doesn't work like the other resampling methods? Also Is it possible that the "combine" tool uses another resampling method than the 4 options in the "resample" tool? ... View more

Nope, this doesn't work, because although the cell size is the same, the position of the cell in the "new resampled file" and the combined file is different. Therefore, it will not be the same smaller cells that the two coarser raster datasets are derived from. Hope there is another solution to solving this problem. ... View more

Thank you for this Ian, The problem is that I have already done the analysis, so I have to write the consequences and implications of this. I guess though that a solution could be to try the different resampling methods on the finer raster and see if one of them gives the same result as combine. ... View more

The original raster has the same visible and full extent (numbers around 15000000), while for the newly created, these are very different (the visible being much lower, like around-129). ... View more

The two raster layers have complelety different visible extents. But they have the same full extent. Yes the two raster are aligned when I open them in the same dataframe. ... View more

Thank you for this. I converted the coordinate system used by the dataframe to WGS_1984. This worked but it didn't shift any data around. Then I went into data--> export data --> and changed the spatial reference from raster layer to dataframe and save. This worked in the sense that if I right click on the raster layer and select properties --> source, then the reference system states that it uses wgs_1984. However, the file remains in the same position as the original raster. It didn't change around. Also If I look in data --> export data on the output raster, the spatial reference box still has raster dataset selected (and not data frame) although it is obvious that things have been changed around in the rest of the "export data menu". What do you think about all of this? Do you think that it could be correct that the position of the cells are indeed the same in the original "defined" spatial reference system and WGS 1984? ... View more

Melita, The original raster definition  is as follows: " User_Defined_Equidistant_Cylindrical Authority: Custom Projection: Plate_Carree False_Easting: 0,0 False_Northing: 0,0 Central_Meridian: 0,0 Linear Unit: Meter (1,0) Geographic Coordinate System: GCS_User_Defined Angular Unit: Degree (0,0174532925199433) Prime Meridian: Greenwich (0,0) Datum: D_User_Defined   Spheroid: User_Defined_Spheroid     Semimajor Axis: 6378137,0     Semiminor Axis: 6378137,0     Inverse Flattening: 0,0 " I create a mxd file with three data frames, one with the original raster and one with each of the newly defined raster. Then I add a basemap to each of these. This results in that for the original raster the dataset fits with the basemap. For the two where I have used define projection they don't align with the basemap, and they are very much off. ... View more