Latest Contributions by grahamlangley-edwards

Hello, I am trying to create a contour shapefile from a mosaicked DEM using ArcGIS 10.  When I use the Contour tool in Spatial Analyst, it creates a new layer but it does not draw.  When I Zoom To Layer it zooms out to 1:120,000,000 and still nothing is drawn.  Not sure what the problem is, if anyone has any suggestions I would greatly appreciate it.  Thanks, Graham ... View more

Hi, I have a couple of Landsat 5 tiles from different dates that I am trying to mosaic together with the Create Mosaic Dataset tool.  The problem is that the tile that is displayed on top, where the two tiles overlap, changes for some reason.  It seems that the two tiles are not "sewn" together at a point where they overlap as I thought they would be, but are just displayed one on top of the other.  The one that is displayed on top changes, apparently depending on which tile is taking up the most space in arcmap at the moment.  This creates a problem because there are clouds in one of the tiles and none in the other, so the images seems to shift.  I have attached two screen shost showing the intersection of the two tiles.  The first one, North_Tile, shows the image when the cloudy northern tile is displayed on top.  The second, South_Tile, shows the cloud free southern tile displayed on top.  In the left corner where they intersect you can see a cloud in the first tile and no cloud in the second tile.   Is there a way to get the tiles to fuse together into one image with the north tile on top? Also, I would like to create a more seamless image.  The seam is rather obvious and contains black pixels, shown in the Seamline screen shot attached.  I have already color corrected, the Default Mosaic Method is Seamlines, the Default Mosaic Operator is Max.   So, is there a way to create a more seamless image? Some info on the images:  Pixel type: unsigned integer Pixel Depth: 8 bit Format: AMD Number of Bands: 7 Any help is greatly appreciated... Regards, Graham ... View more

Hi, I have been tasked with orthorectifying several LandSat TM 5 satellite images to the most recent of those images.  I was simply told to rectify all the images to the latest and highest quality image.  However, I don't see how to do this in ArcGIS 10.  I know you can orthorectify images through the Image Analysis window, or through the Create Ortho Corrected Raster Dataset tool, but I don't see how to orthorectify to a specific image using these tools.  Obviously I don't have much experience with this.  I tried simply orthorectifying one image through the Create Ortho Corrected...tool, but it came back with error 000425.  Also the orthorectify button in the Image Analysis window is greyed out so I can't even try it through there.  The images are from the USGS GLOVIS site and are 30m LandSat images.  More info on images: Number of bands - 7 Format - .tif Source type - Continuous Pixel type - unsigned integer Pixel depth - 8 bit Not sure if they have RPC values, how does one find that out by the way? I selected .tif for the output when I tried to orthorectify the single image with the Create Ortho...tool.  Any help would be greatly appreciated. Thanks, Graham ... View more

Hello, I am attempting to make a simple calculation with the Raster Calculator in ArcMap 10.  I successfully carried out the same exact calculation yesterday using the exact same formula, so not sure what the problem is.  The calculation is: "ndvi_08_06"  > 0.5, which will give me all cell values classified as .5 or greater.  This worked fine yesterday, but when I tried it today on the same dataset it returned this error: "ERROR 000539: Error running expression: rcexec() <type 'exceptions.RuntimeError'>: ERROR 010240: Could not save raster dataset to C:\FileLocation\Output\raster5 with output format GRID."  When I went into the Geoprocessing results window and reran the expression form yesterday, it just returned a solid grey result.  If anyone has any ideas, I would greatly appreciate it.  Thanks, Graham ... View more