Latest Contributions by MelitaKennedy

How do I recalculate the spatial index? Hi Simon, Open the data's property page in ArcCatalog. There should be a index tab (or it might be on a general tab). There will be options for adding/removing the spatial index. Melita ... View more

Hello, I have been building up a database of wadi's in western/southern Iraq, by drawing simple lines overlaying satellite data as a basemap in ArcGIS10. I was then intending them to rank the wadi's for symbology reasons. However I find that the first few I created last week have vanished from the feature class I have been adding to. Now, stranger still, those same wadi lines that disappeared appear from time to time upon loading into ArcMap but disappear again on zooming or any interaction with the interface...I NEED some help on this since tracing wadi's is time consuming and I am wasting time chasing this... the data exists in the attribute table and will 'flash' as lines on the map but cannot be selected, edited, highlighted or anything! I have NOT edited the data at all...and I havce no idea what can be done with this issue. Thank you in advance. Maybe try adding or recalculating the spatial index on the layer. Data that disappears as you zoom in or out is often a sign that the spatial index is not working correctly. Melita ... View more

Hello, I am using ArcMap 9.3.1 with ArcInfo license. I am trying to make a negative buffer for a large set of contiguous but non-overlapping polygons. However, out of the 108,087 polygons it skipped 429 of them and left this error message for each of the features it skipped: I know for sure that the polygons are big enough and will not disappear from this negative buffer; they are all a very similar size. I got the FIDs into a column in excel and extracted just these features into another shp and tried the negative buffer again and it only worked on the first one and skipped the rest. I am currently splitting the polygon shp and will batch buffer on each one individually and hopefully it will work. However, does anyone know why this is happening and if there's a better solution? Thanks, James Hi James, Have you tried running the Check Geometry tool? Otherwise, I don't know what the problem could be. Melita ... View more

Help!  I can't get my Geography type spatial data to draw.  I've tried to find info on this on the forums, but no luck.  I've loaded data into SDE 4 different ways. [INDENT]1. Import in ArcCatalog using standard SDE format - Works just fine 2. Create the table in SQL Server with Geography type, register with SDE and load data in ArcCatalog 3. Create and load the table in SQL Server, then register wth SDE. 4. Import in ArcCatalog using the Geography Config Keyword[/INDENT] Case 2, 3 and 4 the data is there in SQL Server and in ArcMap or ArcCatalog the table shows data but nothing draws. I know that I need to use the Geography type on Sql Server because I want all my data in Geograhpic NAD83 and that is the data type that supports it. The command I've used to register the tables with SDE sdelayer -o register -l sde.TZS2,SHAPE -e nac+ -t GEOGRAPHY -R 3 -P HIGH -C TZS2_ID,sde -E 18.865824,-179.864760,71.434459,-66.884958 -D sde -u XXX -p XXXXXXX Where -R 3 is the number for GG NAD83 also have tried -G 4269 instead of -R makes no difference. I've reviewed the logs the only error that is reported is:  load_buffer error -51 on TZS2, rowid 0, where TZS2 is the layer from case 3. I've got ArcSDE 10 SP 1 64-bit installed with SQL Server 2008 r2 64-bit on a Windows Server 2008 r2 Virtual Machine.  Any help would be appreciated! Hi Jeri Sue, I'm wondering about your -E statement. You have -E 18.865824,-179.864760,71.434459,-66.884958 But I think it should be -E -179.864760,18.865824,-66.884958,71.434459 The usage is [-E <{empty | xmin,ymin,xmax,ymax}>] In Esri terms, x = longitude, y = latitude, thus you need to swap values 1 and 2 and 3 and 4. This may well not be the real problem, but I bet it doesn't help! Melita ... View more

Do you mean what the distance is between the two borders (of the two dataset) in the map? The length is approximately 220 Meters. Thank you for your help. Giorgia Hmmm, that could be a datum (geographic coordinate system) issue. However, the Monte Mario or Roma 1940-based zones for Italy have very different xy extents from a UTM zone. It could also be that the two datasets are at different accuracies. Can you find a 3rd dataset that you can use for a 'control'? That is, which dataset appears to be offset? Melita ... View more

Thank you very much for your advice and information. I modified the coordinates, but I have still some problems. 1) layer 1 Horizontal coordinate system Geographic coordinate system name: GCS_WGS_1984 Details Geographic Coordinate System Latitude Resolution: 0.000000 Longitude Resolution: 0.000000 Geographic Coordinate Units: Decimal degrees Geodetic Model Horizontal Datum Name: D_WGS_1984 Ellipsoid Name: WGS_1984 Semi-major Axis: 6378137.000000 Denominator of Flattening Ratio: 298.257224 _________________ Bounding coordinates Horizontal In decimal degrees West: 10.385948 East: 12.477436 North: 47.091793 South: 45.673069 In projected or local coordinates Left: 10.385948 Right: 12.477436 Top: 47.091793 Bottom: 45.673069 2) layer 2 Horizontal coordinate system Projected coordinate system name: WGS_1984_UTM_Zone_32N Geographic coordinate system name: GCS_WGS_1984 Details Grid Coordinate System Name: Universal Transverse Mercator UTM Zone Number: 32 Transverse Mercator Projection Scale Factor at Central Meridian: 0.999600 Longitude of Central Meridian: 9.000000 Latitude of Projection Origin: 0.000000 False Easting: 500000.000000 False Northing: 0.000000 Planar Coordinate Information Planar Distance Units: meters Coordinate Encoding Method: coordinate pair Coordinate Representation Abscissa Resolution: 0.000000 Ordinate Resolution: 0.000000 Geodetic Model Horizontal Datum Name: D_WGS_1984 Ellipsoid Name: WGS_1984 Semi-major Axis: 6378137.000000 Denominator of Flattening Ratio: 298.257224 _________________ Bounding coordinates Horizontal In decimal degrees West: 10.362326 East: 12.504936 North: 47.129382 South: 45.640333 In projected or local coordinates Left: 606088.187500 Right: 766033.625000 Top: 5220491.203121 Bottom: 5059756.878740 I can see the map with the two layers, but the borders don't coincide. (layer 1 represents municipalities, layers 2 represents the provinces where those municipalities are located) I also changed layer 2 in GCS_WGS_1984 but I have still the same problem, that is, borders don't overlap. 2bis) layer 2 Horizontal coordinate system Geographic coordinate system name: GCS_WGS_1984 Details Geographic Coordinate System Latitude Resolution: 0.000000 Longitude Resolution: 0.000000 Geographic Coordinate Units: Decimal degrees Geodetic Model Horizontal Datum Name: D_WGS_1984 Ellipsoid Name: WGS_1984 Semi-major Axis: 6378137.000000 Denominator of Flattening Ratio: 298.257224 _________________ Bounding coordinates Horizontal In decimal degrees West: 10.387225 East: 12.478793 North: 47.093540 South: 45.674821 In projected or local coordinates Left: 10.387225 Right: 12.478793 Top: 47.093540 Bottom: 45.674821 Is there anything else I can possibly do? Thank you. Giorgia Hi Giorgia, Approximately how far apart are the two datasets? Melita ... View more

Hello! I'm facing a similar problem as my projection doesn't match up. Layer 1 Projected coordinate system name: WGS_1984_UTM_Zone_33N Geographic coordinate system name: GCS_WGS_1984 Bounding coordinates Horizontal In decimal degrees West: 10.511349 East: 10.511368 North: 0.000425 South: 0.000412 In projected or local coordinates Left: 10.385948 Right: 12.477436 Top: 47.091793 Bottom: 45.673069 Layer 2 Projected coordinate system name: WGS_1984_UTM_Zone_33N Geographic coordinate system name: GCS_WGS_1984 Bounding coordinates Horizontal In decimal degrees West: 16.362326 East: 18.504936 North: 47.129382 South: 45.640333 In projected or local coordinates Left: 606088.187500 Right: 766033.625000 Top: 5220491.203121 Bottom: 5059756.878740 What can I do? I tried to export data setting the data frame's coordinate system, but it didn't work. Your help would be highly appreciated. Giorgia Hi Giorgia, Your data has a similar issue to Anja's. Layer 1 should be defined with a geographic coordinate system. See how similar its projected/local extents are compared to layer 2's decimal degree extents? Anyway, try defining it as WGS 1984. Now, about layer 2. As it is, these two layers will not overlay. The longitude values are different. Layer 1 is between 10E and 12E, while Layer 2 is between 16E and 18E. However, are you sure that Layer 2 shouldn't be using WGS 1984 UTM Zone 32N rather than Zone 33N? I think that would place the data in the same location as Layer 1 and put the data in northern Italy, rather than closer to Hungary. Melita ... View more

Hey everyone, I'm new to the world of GIS so I was somewhat confused when I saw the option of choosing from either a geographic coordinate system or projected coordinate system in arcMap. My first layer is a Landsat 5 image that reads as being in WGS_84_UTM_zone_15_N, which is a projected coordinate system in arcMap. I am trying to display a shapefile over this Landsat image, but the shapefile is in WGS84 which is a geographic coordinate system in arcMap. The input for the shapefile is in lat/long without regard to projection. When I load the shapefile layer, arcMap gives me a warning that the coordinate systems differ, but the shape file still appears to be in the correct place. So my main questions are: 1. What is the difference a geographic coordinate system and a projected coordinate system? 2. The shapefile is in WGS_84 and the Landsat 5 image is in WGS_84_UTM_15. Will this incorrectly affect the placement of the shapefile, or can I simply ignore this warning? Any help would be greatly appreciated! Hi, I might suggest looking over the first topics in the geographic coordinate systems and projected coordinate systems 'chapters' in the help. Here's a link to the GCS one: What are geographic coordinate systems In the installed (or online) help, the map projections section (in v10) is in Professional Library, Guide books. When displaying data that's using a geographic coordinate system, ArcMap uses a 'pseudo-Plate Carree' projection. Basically, we just treat the coordinate values as if they're linear and just display the data. When you added the two datasets to ArcMap, I believe you got the geographic coordinate systems (datums) are different warning message. Even though we can see that both datasets are using WGS84 as the model of the earth, the software does strict checking when comparing coordinate systems. I think the names of the two WGS84 definitions are different enough that the warning message is called. You can ignore it. Melita ... View more

I was going to mark this thread as answered with your suggestion, but apparently that's not possible anymore since moving to these new forums.  Seems kinda stupid that we can't do that now. 😄 I think Leo's answer is probably better! Yes, a lot of people would like that type of functionality. The group involved is looking at several possibilities. Check out the Resource Center Site Feedback forum For instance, the sticky Wish List thread. Melita ... View more

My Environment  [INDENT]ArcEngine 9.3.X[/INDENT]  [INDENT]Visual Studio 2008[/INDENT]  [INDENT]VB.NET[/INDENT]  I have been scouring the forums and documentation for a way to do this.  Please refer to the attached image to follow along with my question.  I am looking for a way to   compute the area of the overlapped portion of FeatureABC on AlphaLayer, by FeatureXYZ on BetaLayer.  I'll tell you below what I've examined so far. Please read that before answering, as this topic is very easily misunderstood.  I dont think a spatial query   ISpatialFilter is appropriate for what I am looking for because that only tells me what RELATIONSHIP features share with each other, such as   FeatureABC intersects FeatureXYZ.   What I need to know is not   "IF" they intersect, overlap, etc, but rather exactly   "HOW MUCH" intersection, overlap, etc there is.   The   IRelationalOperator is no help with this either. Like a spatial query, it only reveals whether or not there is a relationship, but does not quantify "how much" that relationship is.  I also don't think that the   ITopologicalOperator will work as it literally modifies the polygon being examined. I do not want to modify any existing feature polygons.  I don't think   GeoProcessing Tools will work because they want to create additional layer files, etc. Very messy. There has to be a simpler way than creating additional layers, then loading them, then examining them, then unloading them, then deleting them. That's rediculous.  I don't believe that envelopes will work either because if envelopes can only be square or rectangular shaped, then clearly they cannot tell me the area as pictured in the attachment, as it is random shaped, not square. All examples I have seen with Envelopes, they are always square shaped, and nowhere in the documentation does it even suggest that an envelope can be anything but a rectangle  I would need an envelope whose shape exactly matches that of the polygon in question.  The solution requires two critical parts   (1) I be able to do this without modifying or affecting the polygons participating in the operation.  (2) I don't want to create any new layers or features which must be added to my map in order to compute this. I just want something I can do in memory and easily throw away.  So if your suggested technique requires that a new polygon be created, but in memory only, and I can examine it through a reference to it, but it does not participate in my map in any way, that's fine.  I'm still in shock that this isn't a massively popular topic as I've yet to find anything in the documentation on this exact idea, nor apparently has anyone attempted it in the forums.  So please don't point me to another forum post which is only remotely related to this topic as I have already looked at hundreds of them, and none appeared to be relevant.  Thanks a lot.  I'm sure your suggestion will help lots of people... if not in the past, then in the future. I am pretty sure you will need to do this in a few parts. First, use ShapeCopy for one of the input geometries. Then, use ITopologicalOperator5::Intersect or ITopologicalOperator6::IntersectEx to return a geometry that is the intersection of the two features. You will then have to calculate the area of this geometry with IArea. You may optionally want to project the intersection geometry into an equal area-based projected coordinate system. Melita ... View more

I am making some maps for a book. I usually use South Polar Stereographic for my maps.  I want page "up" to always be north. I can get ArcMap to rotate the map using Layers->Properties->General, but then I'm just doing north by eye. It seems that there has to be some way of getting ArcGIS to rotate it so that "up" is north.  Anyone know how to do this?  Thank you in advance. I'm using ArcGIS 10. Change the central meridian of the projected coordinate system? ... View more

Hey Guys, I am calling Project on IGeometry (its an IPoint) and its updating the Spatial Reference but not the X and Y.  Any ideas on what could be causing this? Point X, Y, and SpatialReference.Name before projection: -111.500208333333 52.7583416666666 GCS_North_American_1927 and after projection: -111.500208333333 52.7583416666666 NAD_1927_UTM_Zone_5N This is what I expect to see after the projection: 3040679.65085327 6998991.0570187 NAD_1927_UTM_Zone_5N Cheers, Ian Hi Ian, The point's too far away from zone 5, which has a central meridian of -153. We set a limit of 45 degrees of longitude from the central meridian in ArcGIS. If a point falls outside the horizon, it's unchanged. I can project the point in the underlaying projection engine directly, but I don't get those exact values (3214331.2658 6691441.5288). There aren't many transverse Mercator implementations which could take those XY values and return back the given lat/lon values. -111.5 is in zone 12N. Melita ... View more

A shout out to all my international GIS users! I've been asked to seed a geodatabase for some clients working in the North Sea & was wondering if anyone can help me identify a good standard (OOTB) projection for this data.  they have been unable to provide me any data yet, so i'm kind of flying blind. thanks! The EPSG Geodetic Parameter Dataset (http://www.epsg-registry.org, disclaimer: I'm on the committee) lists some ED50-based transverse Mercator zones. ED50 / TM 0 N is used by Shell. There's another one for Netherlands offshore with a central meridian at 5E. There are also ED50 and WGS84 UTM zones, but they may be offset a little for the area of interest. Melita ... View more

Hi, I'm trying also to migrate my code from v9.3 (where it runs fine) to v10 but without any success. The error I'm getting is the same to what the other folks report here: "Retrieving the COM class factory for component with CLSID {7B5B7020-C4F6-11D1-BC92-0000F875BCCE} failed due to the following error: 80040111". I have followed all the instructions posted on the ESRI website about the migration. My code uses only the ArcGIS engine and debugging completes with no errors (C#, VS2008SP1). The binding to the appropriate ArcGIS runtime works fine, the license initialization the same but when I try to create a new instance of the SpatialReferenceEnvironment I get the exception above. In case you are wondering, the ArcGIS Migration Code Analyzer doesn't throw any errors when I test my projects (only a warning that I have to change the target CPU to x86). Can somebody help? Thanks K. Hi, Are you setting the licensing information? See earlier posts in this thread, or this blog entry: Migrating to Engine 10 Melita ... View more

Hello, I read that the geoid is very close to the real earth shape(less than a meter off the MSL) and that it is at most 100m away from the WGS84 spheroid, then I saw such models where the MSL seems to be thousands of kilometers away from any spheroid, are those hugely exaggerated and inaccurate models or am I misunderstanding something? (from my understanding 100m shouldn't be noticeable and a good earth model should be a spheroid - almost a sphere - 22km difference between the spheroid axis shouldn't be noticeable as well). Thanks for the help. The geoid model: See original post for the graphic Hi, Yes, it's definitely been exaggerated. I seem to remember reading somewhere that the surface of the earth is smoother than the surface of a bowling ball (relatively). There are some numbers here: http://www.geography.hunter.cuny.edu/tbw/GTECH201/notes/5.Earth.Coordinates.Grid.Coordinate.Systems.Notes.pdf on page 5. Melita ... View more