Latest Contributions by MelitaKennedy

Hi, You could define a custom coordinate system, perhaps transverse Mercator, with the central meridian set around 54E or 55E or a Lambert conformal conic. Another possibility is to use one of the UTM zones. It looks like more of the country is in 39N, but is there's more development in 40N. If you decide to go with an existing projected coordinate system, you could choose 40N. You'll have several degrees of data 'outside' the zone, but transverse Mercator can project/unproject cleanly. Melita ... View more

That's...interesting. The data appears to line up better at the edges (North/South America), not so good in the middle east and west portions (Africa, Japan), horrible middle/east south (New Zealand). If it was a sphere/ellipsoid issue, I would expect it to be symmetrical. I almost feel like one is using a different projection, but I've no idea what it could be. Because the edges still work, mostly likely a cylindrical projection like Gall's or Plate Carree. Melita ... View more

Is the central meridian at +100 or -100? I would expect differences to be worse farther from the central meridian, but if it is +100, you said you're seeing larger differences around +75. Melita ... View more

How big are the differences? As Jim says, I wouldn't expect any problems when converting between close central meridians. To confirm, the TM 0 is using CM=0 while 31N has a CM=3. If you're seeing issues around farther from +3, it may be possible due to the limitations in the TM inverse. What ArcGIS version are you using? At 10.1, we upgraded our TM inverse so that it would reliably 'round-trip' out to about 85 degrees from the central meridian. Before that, you could see creep at around 8-9 degrees from the central meridian at mid-latitudes, and close at higher latitudes (like the North Sea). Melita ... View more

If you're generally working in one or two states, look for a state GIS depot (search the state name and GIS) like Ohio's is OGRIP. A big university library in the state may also maintain a list of GIS data resources although some may be available to university-affiliated people only. For national level when the sites come back up (currently shutdown in October 2013), USGS including nationalmap.gov. If you're working in a lot of areas, I would still suggest focusing on one area first to help focus on learning the software and data resources. Melita ... View more

I think you're selecting the "open map" (file folder icon) option. That would be used to open an existing map document (.mxd). Look instead for the Add Data button. It's a + sign on a box. Or click File, Add Data. That should let you browse to the TIFF file location and add it to the current map document. Melita ... View more

Hi, Normally, I would recommend that if the two layers are overlaying reasonably well, to ignore the difference coordinate systems. If you want to update the coordinate system of one layer, use the Define Projection tool, or add both to ArcMap, set the data frame to the coordinate system you want and right click the other layer in the table of contents and select data, export data (pick the use-the-data-frame option). However, the differences between NAD 1983 and CORS96 should be relatively small--about a meter at most. How much of a difference are you seeing? If it's more than that, something else like an incorrect coordinate system definition may be happening. Melita ... View more

Not an "official Esri" statement and I always feel nervous doing this. However, I found statement about the 10.2.1 release schedule in the UC2013 Q&A: What is version 11, is that the next ArcGIS release? It says "end of 2013" for 10.2.1. Based on the current internal schedule and what I know about where we are in the release process, we're still on track. ... View more

I just tried a simpler version and the Project method worked. My test values were: 14SPH7560307702 -97.0000043106172  37.9999967618346 675602.999999999  4207702 My guess is that there's an issue with the input MGRS string or, if you're getting lat/lon values, something with them. Are you sure that the lat/lon value is within or near UTM zone 14 North? Melita ... View more

I don't think there's a downloadable trial of ArcInfo Workstation. However, the ArcGIS for Desktop trial includes the Data Interoperability extension which says it supports SDTS as an import format. SDTS rasters are also supported out-of-the-box so just try adding the SDTS data to ArcMap. Disclaimer: I'm going by help documents, so my answer may not be correct! Melita ... View more

Hi Silvia, I just looked at an Imagine file that said it was WGS 1984 UTM 15 North, but the parameter values of WGS 1984 were incorrect. Try redefining the input raster's coordinate system, then run the Project Raster Tool (the output definition must also be on WGS84). Melita ... View more

The first method is used to convert from an ArcInfo Workstation-style coordinate system. Those are used with coverages, grids, and tins and stored in a prj.adf file. ... View more

Hello, One of the common methods of placing the standard parallels is to calculate the north-south extent of the data, divide by 6 and then calculate the latitudes 1/6 from the northern and southern edges. Melita ... View more

Go check your post on GIS Stackexchange, please. ... View more

Isn't 'guys' gender-neutral now? 😄 I'm attaching the 10.2 list of well-known ID and text for geographic, projected and vertical coordinate systems. This may be a later version than what's currently in the File Geodatabase API so please double-check that a definition is supported. Melita ... View more