Latest Contributions by MelitaKennedy

Hi Melita, This topic has been around for a while (see http://forums.esri.com/thread.asp?c=93&f=984&t=189688). Are there any news regarding geodetic area calculation in ArcObjects? Will the approximation methods be made available to developers? Best regards Fridjof Hi Fridjof, We have been working on it but it's a little early to state which software and/release it will be in. Melita ... View more

Dear Melita, Thank you for VBA sample, it did help us. While exploring this combination of transformations, we have spotted some problems. We are trying to do transformations from Gauss-Kruger to ETRS89 using combination of Helmert transformation of 7 parameters and custom grid-based transformation. Grid has cells of 1000x1000 meters, and covers entire territory of Serbia, is based on residuals from Helmert transformation, while for gridding method was used Inverse Distance to a Power, with radius of 10000 meters. Doing such transformations, we got results that differs from results we got using other software (non-GIS) that calculates transformations: 95% of coordinates were exact, whilst 5% were wrong (not satisfying standards of our client, since coordinates must have error not larger than 10 cm). By researching all the methods we have used, we spotted that NTV2 custom grid in ArcGIS is in arc-seconds. Is it possible to have custom NTV2 grid in Cartesian coordinates rather than in arc-seconds, in ArcGIS? Also, is there a tool that can convert grid from ASCII to GSB format in ArcGIS? Thank you in advance! Best regards, Vojkan Gajovic, GISDATA Belgrade Serbia Dear Vojkan, Unfortunately, the software is set up so that a 'geographic transformation' (datum transformation) must be between two geographic coordinate systems. Werner Flacke at ESRI-Germany wrote tools a few years ago (for 9.1 and 9.2) that could convert a shapefile to an NTv2 file (it's still in ArcScripts), but I don't believe the source code was released. There was a thread recently on the PROJ4 mailing about converting some Dutch information into an NTv2 file: http://lists.maptools.org/pipermail/proj/2011-April/thread.html#5634 It mentions that a recent version of GDAL now supports NTv2 as a format. Melita ... View more

Thank you! Am I supposed to mark this thread as answered or something? There's no way to do so. The Esri team that works with the forum software is working on adding that type of functionality. I supposed you could rate the thread high, but you don't need to. Melita ... View more

Hi, if I want to project a point from one SpatialReference to another SpatialReference with a different datum (using GeoTransforamtion), the Z-Coordinate should be changed. At IGeometry.Project(...) it is mentioned that "The Z and measure values are not changed by the Project method." But the IGeometry2.ProjectEx(...) doesn't work either. Is there any way other to project Geometries that I'm not aware of? Thanks Hello Thomas, We aren't yet doing any vertical (z) transformations, even when the input/output z values represent ellipsoid-based heights. We do plan to add this functionality, but it will be in a future release. Melita ... View more

Thank you for your time. I have used the prj-files successfully in other scenarios, thats my reason to believe they work. As cooIn I use the file "SWEREF99 TM.prj" and for cooOut "RT90 25 gon V.prj". I found them under (App-Folder)\"Coordinate Systems\Projected Coordinate Systems\National Grids\Sweden\" My test coordinates is: x = 7454204.638 y = 761811.242 The result (in RT90 25 gon V) should be: pnt.X = 7453389.762 pnt.Y = 1727060.905 I'm using ArcView 9.3.1 and ArcGIS Desktop SDK .NET 9.3.3000. Hello Roger, I may have an answer. You have to remember how US-centric ArcGIS is. In ArcGIS, x = easting = longitude y = northing = latitude Try swapping the x and y values and you should get a better results. ArcGIS usually doesn't apply any geographic (datum) transformations automatically. You may want to switch to using IGeometry::ProjectEx and set up a GeoTransformation. It looks like the code is 108212 for SWEREF99 to RT90 so you apply this with esriTransformForward. To create it, use ISpatialReferenceFactory::CreateGeoTransformation. Melita ... View more

I guess I didn't explain myself very well. I am trying to overlay proposed shovel test locations (I'm an archaeologist) on a project area in 30 meter intervals. Normally, I just create points by hand, but this project area requires more than 2000 shovel tests... the measured grid shows what I need, but I can't seem to convert the graphic so that I can delete extraneous points, and only show the "dots" in my project area... I know that there is an easier way, but can't seem to find one other than creating each stp point by hand.. How about the Create Fishnet tool? It creates a polyline or polygon feature class, but there's an option to create label points. If you use the polyline option with create label points, you'll get a point feature class. Melita ... View more

The code looks okay to me. Are both spatial references valid? What are they and what's a sample input point? What version are you using? Melita ... View more

Hello, I'm looking for insights on why the spatial reference of an IMG raster (it's big, that's why it's in IMG format) displays as 'NAD_1983_Albers' in ArcGIS 10 and 'USA_Contiguous_Albers_Equal_Area_Conic_USGS_version' in ArcGIS 9.3.1.  This inconsistency is present in Python SpatialReference objects (both arcpy and arcgisscripting flavors) and in the ArcMap Layer Properties GUI.  I can code around it, but it seems like a potential bug. Thanks, Lisa Hi Lisa, Esri stores coordinate system information by well-known ID (wkid aka "code" or EPSG code) and by well-known text (WKT). Sometimes Esri adds a coordinate system with a particular name, then EPSG, an external authority, adds the same definition with a different name. Each also has different wkids. When we can we will update an Esri entry to use the EPSG wkid because that's a more widely accepted authority. Rasters are more complicated than vector data because of the different formats. The coordinate system information is stored differently in the various file formats. In this case, possibly the wkt from 9.3.1 is mapping to the 10 wkid, which has a different wkt in the IMG format code! Melita ... View more

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