Latest Contributions by NeilAyres

Not sure if this will answer the question but... When creating the geometry object, it is vital (esp with GCS coords) to provide a spatial reference as well. So line 53 above could be changed to : pointGeometry = arcpy.PointGeometry(arcpy.Point(longValue,latValue), SR) Or something like that anyway. Get the SR from the Describe object of the created feature class. This has been a source of some confusion for me in the past in that arcpy has 2 sorts of "point" geometries. Those created by arcpy.Point(X,Y) which can be inserted into polyline or polygon geometries (at which point the SR is applied), and those created by arcpy.PointGeometry(arcpy.Point([X,Y]), SR). The help files are not particularly good at explaining the difference. Cheers, Neil ... View more

Jeff, as you can see from the function chain pic attached, I was using the image analysis window. As I see it, because you get an "rpc" file per band, you have to do the ortho rectify on each band first then pass that on the composite / pansharp function afterwards. I have found that doing everything, all together in a mosaic is not always (well, lets be honest, never) the best way. Generally I do all the messing about using the image analysis workflow. Then export out the final version into a fgdb, then mosaic the various scenes. N ... View more

Bruce, if you look at your table there are several columns given the coordinates in different formats. The "Easting" and "Northing" columns appears to be State plane feet. So if you had used these in the MakeXYEvents, the points would have been created directly in the stateplane projected system. LONG_DD & LAT_DD are exactly what they call themselves, Lat/Long degrees decimal. N ... View more

Rangunathan, exactly, you have to chose the correct transformation. If this is has answered your problem, please mark the post as such. N ... View more

Bruce, The properties page of your layer indicates that you created the points using state plane (feet), NOT degrees decimal. I think that might be a bit of a problem. When you load a table into make XY events, you have to specify the correct XY columns & what the numbers in those columns represent, ie the correct coordinate system. Neil ... View more

Did you set a transformation (datum shift) under the cords tab in the data frame properties page? You have a single geocentric transform available (ArcGIS v10.2) for WGS84 to/from Kandawala, dx, dy, dz parameters -97.0, 787.0, 86.0. That will be the likely cause of your 200m shift. Neil ... View more

Are both data layers in the same coordinate system? Check this and if not, project one of them to the other. N ... View more

You are quite correct that the raster should be georeffed into its real projected system. But if you have a graticule on the map marked in GCS you can enter these cords directly. After clicking on the "from" point using the GeoRef toolbar, if you right click, it gives you the opportunity to type in the known coords of the point in DMS or DD, these locations are then immediately projected into the PCS units, and will appear in the link table as metres or whatever it is. This is particularly useful when georeffing scanned map sheets where the corners are usually marked in Lat/Long but the map is UTM or whatever. Good luck, Neil ... View more

If these tiffs are going to be used in a mosaic or by other software, it is probably wise to rectify them into the new coordinate system. Be aware, of course, that this creates a new image file and you will need sufficient disk storage for this. As these are aerial photos, use cubic convolution as the resampling technique. You could also select LZW compression which will make the tiffs a bit smaller. But that window you posted has the cell size as 0.000006, which tells me that you are still georeffing into GCS degrees units. Why is that? A proper projected coordinate system in metres or feet or whatever is your standard will be better. N ... View more

Ken, my comment about scale was just about the data source like 1:50k aerial imagery or whatnot. Of course, when creating links it is probably good practice to always use the same zoom level scale consistently (say 1:5000, or 2000 etc). Again this will depend on the input data source. This cell size you have : Cell Size = 1,1 Is this 1 meter by 1 meter? Is this before starting to georeference, when looking at the image properties in Catalog? If so this is just a pixel. If it is after georeferencing, then I am a bit mystified. It seems hard to imagine how you would get the georeferencing so exact as to give you 1m instead of 1.02341999....m ... View more

Wouldn't SA tools / Local / Cell Statistics do what you need? Good luck, Neil ... View more

As long as the input points have a correctly defined spatial reference in UTM, you can.... 1. Load the data into a new ArcMap session, right click somewhere in the data frame to bring up the df properties dialog, go to the coord sys tab, select your desired coordinate system (see Continental / Africa). 2. Or use the Project tool from the toolbox. This will create a new feature in the output coordinate system. Also from step 1 above, you can right click on the layer in the toc, and export the data. Use "coord sys of df" option to write out a new feature in the new projection. Good luck, Neil ... View more

Are your test variables unique identifiers? I would think that the logic should go something like this... Open search cursors on both Fcs. Perhaps load the relevant data into 2 dictionaries or something. Run Daily Fc against All Fc and do your test. If you get a match, construct a list of identifiers in Daily Fc that do match (perhaps using the OID). Then you need to switch this to the ones that don't match. A technique I have used in the past (picked up from the very clever people on this forum) is to use sets. Like : IDsMissing = list(set(list of all IDs in Daily Fc).difference(set(list of found match IDs))) This give you a list of the IDs which don't match. Use this to make a feature layer using a select statement. Copy this feature layer to a temp Fc. Append this into All Fc. Good luck, Neil ... View more

If you were talking about a printed map I would think about it this way... On a very finely drawn map, a line would appear to be about 0.2mm width, this equates to a pixel size of 10m (0.2 X 50,000 / 1,000). Then there are all the other things to consider, generalization and detail at that scale. But if that's what you've got, go with it. Just be aware of the potential pitfalls. Good luck, Neil ... View more

Ken, the to link coords and the reported rms error will always be in the referencing coordinate system. So the 8 will be metres. As regards the question about accuracy, well I suppose that depends on the pixel size or original intended scale of the data. If the referenced tiff has a pixel size of 0.5m, then 8m might seem a little off. If its 4 or 5m then you probably won't get any better. This also depends on the accuracy / scale of the reference data as well of course. Cheers, Neil ... View more