Latest Contributions by MelitaKennedy

No, I am looking for transformation from NAD1983 to NWS84 (Radius 6370 km spheroid). Ah, I haven't heard of NWS84. There are no transformations from a geodetic datum-based geographic coordinate system to a sphere-based geographic coordinate system. We do have a GCS already built with a radius of 6370000 m. It's called "Sphere EMEP". There's a geoprocessing / ArcToolbox tool called Create Custom Geographic Transformation. Use NAD 1983 for the input/from and Sphere EMEP for the output/to. For the method, if you have version 10, use Null. If you have 9.3.1, use Longitude_Rotation. If you do the conversion and the data is offset strictly north-south by kilometers, define a second transformation. This time use Geocentric_Translation for the method and leave the parameter values set to zeroes, and see if that works better. Melita ... View more

What transformation method will be best suited to convert the datum from NAD83 to NWS84? Do you mean WGS84 also known as WGS 1984? Try NAD_1983_To_WGS_1984_5. If the data is in the lower 48 states (except maybe the west coast states) and accuracy is a meter or more, try NAD_1983_To_WGS_1984. Regards, Melita ... View more

I have a map layer of facility locations (points) in the Lambert Conformal Conic projection.  I used the buffer tool to place a 3 mile buffer around each facility.  I also have a layer of census block centroids that is in the same projection.  I intersected the buffers with the census blocks to determine which blocks are within 3 mi of a facility.  This worked fine.  Next, I took the census blocks that are within 3 mi of a facility and projected from Lambert to UTM zone 10 (facilities are in Washington state).  Within the UTM coordinate system, I see that some of the census blocks that were barely within the 3 mile buffer in Lambert are now just outside of it.  For example, in Lambert one census block was 2.999 miles from the facility, but in UTM 10 it is 3.18 miles away.  I know there differences in the projections and perhaps the datums, but this seems like a big error.  Did I do something wrong?  What kind of differences should I see between Lambert Conformal and UTM in the western part of the U.S.? Thanks Hi Steve, I'm not really surprised, and there are several things that could affect this. Neither projection maintains distances. They're both conformal which maintain shapes. A UTM zone is designed to have distortions no worse than 1 part in 2500: thus the 0.9996 scale factor parameter. It also depends on the parameter settings in the Lambert conformal conic projection. The data may be in a different location relative to the projection's standard lines (where scale is 1.0) than when using UTM. Another problem may be due to the Buffer tool creating a circle with circular arcs rather than a densified polygon. When projecting a circular arc, we maintain it as a circle. It's possible that the buffer would change more if it was composed of densified points. Melita ... View more

I'm aware that going from arcgis -> illustrator is quite common. But I have the inverse problem. I have some vectors in illustrator that I want to open in arcgis. I tried to save in various autocad options but not once did they appear in arcgis, even though I checked the autocad layers and all the vector points were there. Here are the files. pdf http://docs.google.com/leaf?id=0B9wNtQ9NGRHuNmExYzA2NzEtOWZlYS00ZDViLTk2OTgtNDY4ZWE5YTNiZmUz&hl=en&authkey=COa3y7gC ai http://docs.google.com/uc?id=0B9wNtQ9NGRHuNmVkMjZjZWEtMTc2Ny00NDE3LTgxNmMtNTk0NTliMDA0OTFi&export=download&authkey=CIHK_5gE&hl=en svg http://docs.google.com/uc?id=0B9wNtQ9NGRHuMGRhYjQ1NDAtMzk5MS00ZDQ1LWIzYWUtM2E2NjM1OGRiODhj&export=download&authkey=CLyKoc0I&hl=en If someone can tell me why the autocad import doesn't work that would be really helpful. Thanks When you convert the features, are the coordinates in a particular coordinate system? If so, maybe you just need to define the coordinate system (so ArcMap knows how to overlay the data). Or you may need to georeference (if raster/CAD) or spatially adjust if vector the data. Melita ... View more

I have a DWG with these notes: 1. All coordinates are ground & adjusted to NADCON, +- 12 to 18 cm. 2. NAD 1983, NAVD 1988 3. Combine Factor = 0.99969305 4. Benchmark used NGS J-432, Published Elevation 5129.15 5. NM State Plane, Western Region I want to bring the file in to an existing ArcMap project where the Data Frame coordinate system is NM State Plane West NAD 1983 feet. I have tried to transform the file by adjusting the scale under the layer's Transformations tab but the points aren't moving where I know they should be located. Specifically, I click the Enable Transformations check box, click the Rotate, Scale, Translate radio button, and enter values of 0.99969305 or 1.00030695 in the Scale box. (I have tried both numbers.) What am I doing wrong? I've done it in ArcMap before but it's been a few years and obviously I am missing something. Aaron Allen Albuquerque, NM Hi Aaron, btw, when I inverse your scale values, I'm not matching. My calculator reports 1/0.99969305 is 1.00030704 while 1/1.00030695 is 0.99969314. Anyway, another way is to incorporate the combined scale factor (CSF) into a custom projected coordinate system. What you'll need is the CSF that converts to ground. You multiple the false easting, false northing, and scale factor values by the CSF to create new projection parameter values. Thus, the new pcs reflects the 'ground' coordinate system. I would suggest modifying the pcs name to reflect that the parameters are adjusted. Melita :cool: Read this section if you're interested in the math: When a projection is done the final values are calculated by: X_grid = false easting + sf*(bunch o'math) Y_grid = false northing + sf*(bunch o'math) where the other projection spheroid parameters are used to calculate the 'base' XY values. A CSF is applied to the final values: X_ground = CSF*X_grid Y_ground = CSF*Y_grid substituting in: X_ground = CSF*(false easting + sf*(bunch o'math)) Y_ground = CSF*(false northing + sf*(bunch o'math)) or X_ground = CSF*false easting + CSF*sf*(bunch o'math) Y_ground = CSF*false northing + CSF*sf*(bunch o'math) So we get: new false easting = CSF*false easting new false northing = CSF*false northing new scale factor = CSF*sf ... View more

Would anyone have a clue as to why it is that when I publish a map with the WGS 1984 Web Mercator (Auxiliary Sphere) the WKID is defined as 3857. In the help docs it states that it should be 102100 but I can never get my map services to show up that way. Further looking at the WGS 1984 Web Mercator (Auxiliary Sphere) prj file shows it is defined as 3857, so how does any one else get 102100 to show in the REST page? Even if I manually change the code in the prj I cannot get it to say 102100. Does anyone else have this issue? Running AGS 10 ADV ENT. The WKID was changed at version 10 to 3857. This is because this version of "web Mercator" closely aligns with the EPSG dataset's entry (http://www.epsg.org). Doc's out-of-date, I'll ask that it be updated. The multiple codes are due to release timings: A. 102113 (because that was the only way we could emulate the web services' definition) B. 102100 added next, using a differently built, but *completely* equivalent, definition C. EPSG then added 3857 (and deprecated their earlier 3587 entry which was closer to how 102113 was defined) D. We changed the ESRI 102100 code to EPSG 3857. Melita ... View more

Hey Derek- your link sends me to a place called salesforce.com; is this where we need to go and then sign up for a free 30 day trial?  Seems kind of odd... I had the same problem when the Ideas site was first opened. Try http://ideas.arcgis.com instead. Melita ... View more

Hello - I am using a Geometry Service in the Flex API, to convert a point from WebMercator to Albers. The direct conversion did not work, so I first converted the point to WGS 84, and that worked fine. When I go from WGS 84 to Albers Equal Area Conic, though, the code errors out. If I try to do the projection using the ESRI sample service at http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer/project with input wkid= 4326, output wkid=9822, geometry = { "geometryType":"esriGeometryPoint", "geometries":[{"x":-89.137,"y":28.99}] } I get 'error projecting geometries' as you can see here http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer/project?inSR=4326&outSR=9822&geometries={%0D%0A%22geometryType%22%3A%22esriGeometryPoint%22%2C%0D%0A%22geometries%22%3A[{%22x%22%3A-89.137%2C%22y%22%3A28.99}]%0D%0A} How exactly do I get the lat/long projected to Albers? Todd, 9822 is a code for the Albers map projection. That is, the algorithm, not for a completely-defined projected coordinate system. What parameters, GCS, and units do you want to use? Perhaps we have one already defined. There are several variants for US/North America, and some for other continental regions. Melita ... View more

I want to project a raster from WGS84 Geographic to NameBessel2217 which is the projected coordinate system used in Namibia. The problem i have however is that there are a entire list of possible transformations and i am uncertain which to use. Can anyone offer any advice on which transformation to pick? Thanks Hi, Can you give the details on the target coordinate system? Bessel is a spheroid (ellipsoid), not a datum. EPSG (http://www.epsg.org and http://www.epsg-registry.org - online version is running slowly right now; the subcommittee is working on the problem) only lists Schwarzeck (although the Cape and Hartebeesthoek probably also apply, but they don't use Bessel ellipsoid) which does use Bessel Namibia. The transformation to use would be Schwarzeck_To_WGS_1984_2. We have a UTM zone based on Schwarzeck. Otherwise, EPSG lists several zones based on Lo22. These use a south-west oriented system that we don't support. I've been told that you can emulate the Lo systems, by using -1 for the scale factor. Melita ... View more

I run ArcMap 9.1. I have some .dwg files without projections that I would overlay on aerial photos. From everything I've read, it seems that the georeferencing toolbar is the best way to accomplish this, but whenever I load the .dwg files into ArcMap, they are not recognized by the toolbar. The toolbar does work because I have used for other types of image files. Can anyone help me out with this one? Thanks. Austin Austin, In 9.1, the georeferencing toolbar didn't support CAD files yet (unless scanned images). Instead you need to identify two pairs of coordinates in the CAD's coordinate system and in the target coordinate system. You can put them into a CADname.wld file: x1_source, y1_source, x1_target, y1_target x2_source, y2_source, x2_target, y2_target If you open the CAD layer's property page (in ArcMap), you can add some transformation information there instead. There's information on this in the help. Here's the web link: http://webhelp.esri.com/arcgisdesktop/9.1/body.cfm?tocVisable=1&ID=222&TopicName=Applying a coordinate transformation to a CAD layer or via your installed help, ArcMap, Creating Maps, Applying a coordinate transformation... Melita ... View more

Hello and thank you in advance. I am still, unfortunately, a little confused on the projection for posting data in Google Earth: I understand that GE and MS apps use a spheroid only model, which is the projection ESRI calls: Geographic Coordinate System, (spheroid-based)  "GCS_WGS 1984 Major Auxiliary Sphere" or Projected Coordinate System (World) "WGS_1984_Web_Mercator" Whereas ESRI uses a spheroid or ellipsoid model, which is the projection ESRI calls: Geographic Coordinate System (World)  "GCS_WGS_1984" or Projected Coordinate System (World) "WGS_1984_Web_Mercator (Auxiliary Sphere)" The instructions in Technical Article ID: 34749 say when using 9.3 SP1 to use the: Predefined Projected Coordinate System (World) "WGS_1984_Web_Mercator" HERE IS MY PROBLEM: When projecting from NAD83 to Projected WGS_1984_Web_Mercator in the toolbox, there is a message that this is an undefined projection, and I can only do it with a double: NAD_1983_To_WGS_1984_5 AND WGS_1984_Major _Auxiliary_Sphere_To_WGS_1984 The same is true (obviously) if I try to project from NAD83 to Geographic GCS_WGS_1984_Major_Auxiliary_Sphere Isn't this exactly the same as just going from NAD_1983_To_GCS_WGS_1984, which is the ESRI model, not the Google Earth or MS (Bing) model, right? In the end, projecting to GCS_WGS_1984 is equivalent to projecting to PCS_WGS_1984_Web_Mercator which is equivalent to projecting to GCS_WGS_1984_Major_Auxiliary_Sphere The only difference is that the denominator of the flattenting ratio for the PCS_WGS_1984_Web_Mercator is infinity instead of 298.257224.   No matter what, the locations lie directly on top of one another and NOT where I can see them (my well points) on the Google Earth image. So, how do folks line up their very locatlized point locations on a Google Earth visualization for their projects/clients? In addition, using the double transform to get to Projected Coordinate System (World) "WGS_1984_Web_Mercator" yields the same projected or local bounding coordinates as Projected Coordinate System (World) "WGS_1984_Web_Mercator (Auxiliary Sphere)" HOWEVER, Google Earth will not import the file "WGS_1984_Web_Mercator (Auxiliary Sphere)"  (says zero features) Why does this happen? HELP!! Nicki Cook Ni Nicki, You're caught in between our transitioning to "WGS_1984_Web_Mercator (Auxiliary Sphere)". Both it and "WGS_1984_Web_Mercator"  will have exactly the same coordinate values for the same location on the Earth. They're just different ways of emulating the coordinate system used by Bing and Google maps when they cache their data. If you access the coordinates as latitude-longitude values, they are WGS84. But what's cached is in a Mercator projection where the math supports a sphere only. For the sphere's radius, they use the semimajor axis (equatorial radius) of WGS84: 6378137.0 meters. So why are there two versions? When we originally made a definition for "Web Mercator", we had only one implementation of Mercator. It contains equations to use with a sphere or a spheroid/ellipsoid. The only way to trigger the sphere equations that are needed is to use a geographic coordinate system (GCS) based on a sphere. We built a custom WGS 1984 Major Auxiliary Sphere for it and defined "WGS_1984_Web_Mercator". Later, we added a new implementation of Mercator that supports a parameter (Auxiliary Sphere Type), which describes how to calculate a sphere's radius from a normal spheroid/ellipsoid-based GCS and use it with the projection. The projection's name is Mercator_Auxiliary_Sphere. Both versions do the same thing, force spherical math. The earlier version, using the custom GCS causes problems because you have to do a geographic (datum) transformation to it, so it's awkward. The 'new' version uses the standard WGS84 definition, so it simplifies the workflow. The version you're using hasn't been updated to support caching your data with the newer "WGS_1984_Web_Mercator (Auxiliary Sphere)". Melita ... View more

Hi Chris, this isn't really an ArcObjects question, well at least my answer isn't.  You can symbolize your layer in ArcMap based on quantities and a proportial symbol.  So if you had a count field in your line feature class defined as a numeric field, you could use that as a quantity.  Then you can set your min and max width and all that good stuff. Given Alexander's answer, I found IProportionalSymbolRenderer in the SDK help. It's in the Carto library. Melita ... View more

bzborow1;18473 wrote: Hi Guys, I'm building a search service to query unprojected attribute data, project it, and deliver the extent back to the client.  The method I'm using works unpredictably.  For are larger land parcels it re-projects perfectly find, but for really small land parcels, quarter sections, it won't reproject using the getEnvelope() method.  Can anyone offer some advice on how I might fix this problem? QUOTE] I am speculating that it could a problem with the resolution/domain values of the target spatialreference (less likely: the tolerance). Perhaps the resolution value is too large and the envelopes are collapsing. Another possibility is that the envelope, after projecting it, is distorted enough that it's collapsing. I think that would be more likely with 'long' sides--they should be densified to reflect what's happening when the data's projected, aren't. Melita ... View more

Thanks very much, Jim! I'm not desperate enough to switch browsers, but that's certainly a possibility. Melita ... View more

We are upgrading SDE from 9.3.1 to 9.3.1(sp1). We downloaded the SDE complete suite but missing the PE.pdb in particular. We could find it in the previous version (e.g. pe-sdk-bin-9.3.1-b1632-windows.zip) for both x32 and x64 platforms. The pdb is important for our development. Thank you so much and we're looking for this file urgently. Eric Eric, Will you contact me at mkennedy at esri dot com? The standard SDKs don't include the pdb (nor debug build) files. There were only two fixes for the projection engine for 9.3.1 SP1. One was for Java: if you tried to retrieve the horizion for several projections, it would crash. The other change was to improve performance when confirming whether two versions British National Grid are the same (we changed the scale factor in 9.2). Melita ... View more