Latest Contributions by MelitaKennedy

Hi Chris, Converting between projected coordinate systems is easy, if the map projection algorithm is supported. In this case, you can either have the data project on-the-fly in ArcMap to the data frame's coordinate system, or create a copy of the data in the base map's coordinate system using the Project Tool (ArcToolbox, Data Management, projections and transformations). The actual steps that occur internally when converting vector data between two projected coordinate systems are: 1. Coordinates converted from projected x,y to geographic lat,lon. 2. If the input and output geographic coordinate systems are different, do a datum transformation if one is specified. [In ArcMap] If not, treat coordinates as if they're already using the output gcs. 3. Convert coordinates to the output projected coordinate system. If the input data is using a gcs, start at 2 instead, and so on. I would use zone 36 North over 35 North, but the area is really too wide for a UTM zone. It would probably be better to map it in a conic projection, but Esri doesn't have any defined already. Hope this helps, Melita ... View more

Hi, If the files are still in Esri GRID format, make a text file called prj.adf and place this text in it: projection transverse units meters parameters 6371204 6371204 0.926 -100 00 00 00 00 00 0.0 0.0 We don't have a separate spherical transverse mercator. Instead, you set the gcs/datum to use a sphere and that triggers the correct map projection equations. If the raster's been converted to another format, try creating a text file called DNAG.prj and put this in it (as a single line) PROJCS["DNAG",GEOGCS["GCS_STM1987",DATUM["D_STM1987",SPHEROID["STM1987",6371204.0,0.0]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",0.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",-100.0],PARAMETER["Scale_Factor",0.926],PARAMETER["Latitude_Of_Origin",0.0],UNIT["Meter",1.0]] Put DNAG.prj into the ArcGIS install location's Coordinate Systems, Projected Coordinate Systems folder. Now you can browse to it and set it as a raster's coordinate system in Define Projection Tool or the data's property page in ArcCatalog. Melita ... View more

I have three shapefiles exported from a CAD drawing (point, polygon, polyline). Judging by where the CAD drawing came in when I first added it as data, it is in a different coordinate system (the architect who sent it seems to like WGS 84; however, I'm using NAD 83 State Plane Texas Central FIPS 4203 since that is what the county uses). Changing the coordinate system in ArcCatalog doesn't 'move' these to where it should be. What am I doing wrong? Sometimes ArcMap will flag me to do a transformation when I add data with a different coordinate system, which usually fixes things. Is there any way to do an 'on demand' transformation on these CAD-derived shapefiles? Hi, The data does need to have its current coordinate system defined, not what you want it to be. Changing the coordinate system in ArcCatalog updates the metadata information, not any extents or coordinates. If it is WGS84 (or NAD83) latitude-longitude, and that's defined, ArcMap can reproject it to the SPCS. With WGS84 defined, if it's not lining up, it may be using something else. If you add it to a new map, what are its extents? Do they look like decimal degrees? If not, can you identify them as SPCS (perhaps on a different datum/GCS, or using different units)? Melita ... View more

Hello, I have several CAD dwg's that I have to bring into Arcmap (9.2).  All of them were using a local coordinate system.  I have the surveyor's notes that say it was based of of the Indiana state plane west by a factor of 0.9999586191...I have no idea how to adjust a coordinate system and I have tried anything I can think of to do so.  Any help is appreciated. Thanks! Hi, One way is to use the CAD file's property page in ArcMap (not ArcCatalog). It should let you apply a scale factor. Another way is to apply the scale factor to the Indiana West definition and create a custom coordinate system. Assign the Indiana West definition to the CAD data. Now open the coordinate system definition and modify it. You'll have to figure out whether you need to apply this value directly or it's inverse. You want the value that will adjust the state plane coordinates TO the adjusted system. You need to apply the SF to 3 projection parameter values: false easting false northing scale factor So if the combined scale factor is 0.9 (let's say) and the projection's scale factor is 0.9998, the new scale factor is 0.89982. Similarly, if the false easting is 100000, the new value is 90000. Melita ... View more

I don't think you're going to be able to load the shapefile itself, but will have to dump out the points into another format first. Some people on other sites were recommending Easy GPS or GSAK I checked and I don't have a copy of DNR Garmin (any version) available locally. The last I heard, it had not been updated for ArcGIS 10. Melita ... View more

You definitely have a few bad points in BankPermits. One is FID = 349. The latitude value is the same at the longitude value, just the sign changed. That's why it shows up so far north compared to rest of the data. FID = 303 has the wrong Northing value (it's currently equal to the Easting value). I don't know what's wrong with point FID = 387, if all the points are supposed to fall within South Carolina. The latitude value is 30.3114 when all other points have latitude values over 31 degrees. For the other points in BankPermits that fall offshore, I don't have a ready answer for you. It's possible that the latitude-longitude values for some points that they may be in DMS rather than decimal degrees. For example, FID = 115 has: latitude = 32.4507 longitude = -80.0103 If we treat these as DD.MMSS and convert to decimal degrees, they become latitude = 32.751944 longitude = -80.0175 Or they could be DD.MMmm which converts to latitude = 32.751167 longitude = -80.017167 Without knowing where the point's supposed to be, I can't tell if either of these is correct. Melita ... View more

Hi Annelise, Normally, this occurs because there's something wrong with the data's coordinate system. If you add the data to a new ArcMap (let the data set the coordinate system of the data frame, what are its extents? I think you will find that they aren't in decimal degrees. If you think there's something odd about the reported numbers, open data frame properties and "clear" the data frame's coordinate system. At this point, you can also add other data and see where it is relative to the problem data. Melita ... View more

Hi Jan, That's correct. When the software 'clips' features to a particular coordinate system, and saves them, it's permanent. We don't maintain the original feature and its clipped version in any permanent way. I hadn't even thought about that reason! Melita ... View more

Hi Jan, Is the problem in the main map or layout data frame, or in the overview window? I haven't yet been able to reproduce the problem in the data frame, and am still trying to get the overview window to work at all! Thanks, Melita ... View more

Hi, It looks like MGRS coordinates. No telling what GCS the coordinates are based on, but the values are only to the nearest kilometer so it doesn't matter. 28RCS1931 UTM zone 28N, R = latitude band between 24N and 32N, etc. latitude = 28.29262 longitude = -16.84571 The lat/lon values are not that precise, by the way. Kilometer accuracy is around 2-3 decimal places when working in decimal degrees. Melita ... View more

I modified the input of the iterator to explicitly point to the source geodatabase file, and now it is working. Excellent! Thanks for letting me know. ... View more

Hopefully, this isn't the problem but you've set the model to not run the iteration only once? See Model menu item, Model properties, integration tab I think it's designed that way for testing purposes. Melita ... View more

I'm not strong on cartographic effects! The buffer might work, but what I would do to avoid any valid/invalid envelope issues is to remove the coordinate system/spatial reference information. Then you should be able to just display the buffered polygon in ArcMap underneath the real data. Depending on how you add that layer to ArcMap, you may get a 'unknown spatial reference, cannot reproject' warning, but you can ignore it. Melita ... View more

Hi Avotas, It's in the same units as the coordinate system: decimal degrees. Melita ... View more

Hi! I used function Conversion tolls/Feature to raster to convert roads from shapefile to raster. Any suggestion why Arcgis 10 made such a result, that shapefile and raster do not match positionally. Created raster should overlay roads positionally, but that didn`t happen. Is there enything wrong with my Environments settings? Here is picture attached. Hi, (As a colleague pointed out, when bringing my attention to your post) It looks like a datum / geographic coordinate system difference. I would expect that Feature to Raster should use the same coordinate system for the output that the input has, but are you overriding the output coordinate system in the geoprocessing environment settings? What are the coordinate systems for the two datasets? Thanks, Melita ... View more