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7

I bet it may be the slight discrepancy between Esri's WKT definition of 26915 and the OGC WKT version. I think the only real difference is in the name (NAD83 / UTM zone 15N vs NAD_1983_UTM_Zone_15N). You could try making a copy of the shapefile, then replace the PRJ file text with the Esri version linked above.


6

One could use either kind of latitude to locate points on the WGS 84 ellipsoid (used by the NED) or any other ellipsoid, but "everybody knows" that the values will always be given as geodetic latitudes. However, it is surprisingly hard to find an authoritative statement to that effect! Before we go on, it helps to understand that although a datum like the ...


4

there are several categories in the utm section of esri crs projected. go to the projected coordinate systems. then to UTM, Then look at the nad83 BLM (US Feet). That should work in both autodesk and esri. (EPSG) 32165


4

The question asks for a rigid motion of the object on an idealization of the earth's surface. For ellipsoids the only continuous families of rigid motions possible are rotations around the earth's axis. But for a spheroidal model there is a three-dimensional family of rigid motions and they can move an object from any location to any other (for two ...


4

The projection part of the .prj file declares units as meters, so that is what you get. If your data is in degrees, you have to use a .prj file for EPSG:4326: GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137,298.257223563]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]] without any projection information. Looking at the ...


4

Usually the Project Geoprocessing Tool is all you'd need. If you don't want a permanently saved projected dataset you could write to in_memory. In Python, if you set the output featureset to arcpy.Geometry() you can use result.getOutput(0) to get a simple projected Geometry object back.


3

First, use Define Projection (from the Data Management / Projections and Transformations toolbox). The metadata specifies NAD 83 in decimal degrees, so, GCS_North_American_1983. This gives the shapefile some spatial reference data. After that, you can use Project to turn it into whatever projected coordinate system you want.


3

To a high relative accuracy, in this application--where the region to be mapped will not extend more than a few hundred meters and it is not near either pole--you can treat lat-lon as a Cartesian coordinate system that uses two different linear units of measure. Each degree of latitude will be approximately 111300 meters (and a more accurate value, which ...


3

There are some free applications that let you try and play with projections. like: indiemapper.com flexprojector They also indicate to what extend they preserve size, shape or direction. Depending on you application a different priority might be set. For instance if I had to map an areal phenomenon like e.g. certain species habitat zones I'd prefer a ...


3

You can cheat, because the EPSG numbers for UTM zones have a pattern than incorporates the zone number. 269ZZ for UTM north zones, where ZZ is the zone number 327ZZ for UTM south zones, where ZZ is the zone number And, since PostGIS uses the EPSG number for the SRID, you're all set.


2

The problems arise because the CostDistance calculations use the (Euclidean) distance in a map as a surrogate for the true distances experienced on the globe's surface. This surrogate will be distorted in two ways: The relationship between map distance and globe distance will vary according to location on the map. At any given point, the map-globe ...


2

Thanks for the clarification. It appears that you are mixing the ArcGIS JS API's map object with the Google Maps API's heatmap functionality. This is highly unlikely to work. Instead you could look at the ArcGIS Server JS API's heatmap functionality. This isn't officially supported but stands a better chance of working - see ...


2

You definitely need coordinates or to join that data with existing polygons/points. A quick look at your data shows that it is broken down into boroughs or district numbers. My next step would be to join this data in ArcGIs or QGIS (whatever solution you have available to you) to either the boroughs or districts. This will allow you to visualize the ...


2

Have you tried making a custom projection? Here is a walkthrough from esri knowledgebase.


2

Open a new dataframe, don't add a basemap, just the shapefile, move your mouse around on the screen and look at the coordinates towards the middle are they small numbers that look like latitude and longitude? Open windows explorer and navigate to your shapefile... look for a *.prj file, if you don't have one, then you are working with data that no ...


2

Once you get the shapefile/projection problem solved: Kriging is a method of interpolating points to create a continuous surface. I think that you actually want to use graduated colors to modify the symbology of the points, manually setting classification breaks at the values you need.


2

I believe that you are probably encountering the same problem that has been discussed in the old Esri Discussion Forums under the aptly named title of "True Curves, True Evil". I have a reproducible (but long) test case of this phenomena in a Python/ArcPy script that I used to convince a client that what we were seeing was explainable and could be worked ...


2

Do not use Set CRS for Layer if you want to reproject your data. It changes only the CRS definition, but does not recalculate any coordinate. So set it back to what it was before (WGS84 I assume), and use Save As ... under a different name and different CRS.


2

How are you obtaining your lat/longs out of curiosity? Without access to a DGPS you will be hard pressed to get sub metre accuracy anyway. This 2 point Coordinate Transformations (Basic) spreadsheet is quite useful. Try to use control points at the outer extremities of your site as the further from these points you are the less accurate the transformation. ...


2

The shapefile from Natural Earth contains the south pole. The Mercator projection is not able to render that point for mathematical reasons (it would be in inifinity). What you can do: Set Project CRS from Layer (that would be EPSG:4326) switch to edit mode Delete the bottom line of the antarctic save the layer Change Project CRS to EPSG:3857 If you ...


2

Those are not not latitude and longitudes. It's (likely) going to be some Projected Coordinate System. The easiest way to figure out which would be to look in the metadata (if it came with any) or contact the agency. They'll know what coordinate system it is. Edit: If for whatever reason you can't get this information from them, I'd start your search ...


2

The coordinates are rather high, so I made a first guess at ft-US units. EPSG:32165 NAD83 / BLM 15N (ftUS) does a good job:


2

Finding the "right" projection is a rather time-consuming process. The best way would be to ask the map creator (if he still lives), but I guess this is not the answer you want. So take a look at available map projections, e.g. at http://www.radicalcartography.net/index.html?projectionref, and compare the shape of the degree grid with your example. At ...


1

Another way to determine what coordinate system it is in (if you have some reasonable guesses) would be to load some existing data with the projection defined and then load the data with the coordinates and change the coordinate system of the data frame (right click the "Layers" data frame) to what you think it might be. Reasonable guesses would be the ...


1

As you mention ArcGIS: You could create a fishnet (Note: the link is for ArcGIS 10.0) for your surface und use the resulting polygons to calculate the number of points inside them. Make sure to choose the right projection, as Andre Joost already pointed out. It sounds like you would need to choose an equal area projection.


1

The answer is given in the metadata. Geographic coordinate system Horizontal datum of NAD83, except for AK which is NAD27 Both versions of NAD (North American Datum) are geodetic systems.


1

Looks like you want a Mercator Projection. Try to save-as your shapefile assigning the WGS 84 / Pseudo Mercator (EPSG: 3857) projection or assign this projection to your project (using transformation on the fly). See also: What is the standard Mercator projection?


1

You'll need to define both a horizontal coordinate system (could be projected, like UTM) and a vertical coordinate system (like NAVD88, making sure to be in the same units as your horizontal). A vertical coordinate system expresses elevations relative to a baseline, usually a mathematical representation of the Earth's surface. Your measured elevations ...


1

solved It: function calculateArcPointsGeo(center, radius, startAzimuth, endAzimuth, segments) { var pointList = [], point, i, d = radius / 1000, // d = distance in km R = 6371, // km, R = earth's radius (mean radius = 6,371km) lat1 = deg2Rad(center.Y), lon1 = deg2Rad(center.X), ...


1

Given your examples above, you must be using "Nearest Neighbour" option to do the resampling in the Project Raster tool. That's why some values "disappear". What else can it do, it takes the nearest value (measured by cell center position) and assigns it to the new cell in the new coord sys. A histogram of the cell values between the old & new can never ...



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