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Questions tagged [m-values]

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2
votes
0answers
17 views

Creating multipoints from points and setting incrementing M value in spatialite

I have a layer of points, which I want to group into multipoints grouping by some column. This part is easy: SELECT name_pre, CastToMulti(GUnion(geometry)) AS geometry FROM sp_survey GROUP BY ...
2
votes
1answer
35 views

Read M value (CoordinateXYZM) from shapefile with geotools

After successfully writing M values into a shapefile (.shp, only points for now), I now also want to read the generated file and print the full coordinate set (x, y, z and m) using geotools (23-...
4
votes
3answers
61 views

Pasting point data into PostGIS with M Values

I have point data exported from Trimble Insphere as .shp. I am trying to paste the data into our PostGIS database but keep getting: PostGIS error while adding features: ERROR: Column has M dimension ...
1
vote
1answer
32 views

Write M value into shapefile with geotools

I'm using the Java 1.8 library geotools (version "23-SNAPSHOT") to generate a shapefile. Opening the resulting .shp file with QGIS was successfull and I noticed that the gemeotry was apparently ...
1
vote
0answers
41 views

View M value in QGIS

I've got a ".shp" file (plus the additional .dbf, .fix, .prj, .shx files) that was created using the geotools library and want to view its data using QGIS 3.8.2. QGIS properly displays all of the ...
1
vote
1answer
42 views

Cannot solely remove M value of Shapefiles

I have a couple of Shapefiles which are of geometry type ZM (like PolygonZM, MultiLineStringZM, etc.), however my database (a PostGIS database) is of geometry type Z (like PolygonZ, MultiPointZ, etc.)....
1
vote
0answers
78 views

Calibrate routes not lining up with calibration points [closed]

I am currently building a model that calibrates Z and M values from Cross Sections for a stream. Z being the 100yr flood and M being the station number. What's happening is the vertex on the stream ...
1
vote
1answer
210 views

Assigning attributes values to PointZM and convert to LineZM Geometries in QGIS? [closed]

I have elevation and measured values in attribute table of points layer. Is there a way to convert this layer into PointZM (with elevation and measured) and assign elevation and measured values to ...
4
votes
1answer
222 views

Recover M-values from PostGIS `ST_Intersection`?

I am querying the intersection of a path (LinestringZM) through a region (MultiPolygon) but the ST_Intersection returns only the Lat/Long/Alt coordinates and I need to recover time, stored in the M ...
2
votes
1answer
66 views

Determining distance on line of point, given measure?

I need to determine into a standalone python script the distance of a point on a polyline with M-values and its' coordinates, at a specific measure. For example, I have to calculate the X,Y of a ...
10
votes
2answers
1k views

QGIS Extract Nodes with M-Values for Linear Referencing

I have a MultiLineStringZM layer in a sqlite database, and I'm trying to visualize the measures or m-values at the vertexes. I've tried looking up information on how to do this in QGIS, and about all ...
1
vote
1answer
301 views

Where can I find some Sample Data for Linear Referencing?

I'm teaching GIS at a Local college, and one of the classes is on Linear Referencing, specifically of Roads. For the Practical classes, I need some Sample Data for Linear Referencing. Ideally, this ...
3
votes
2answers
1k views

Drop M values from MULTIPOLYGON with PostGIS?

The title is self-explanatory. I wonder if there is a simple function like ST_Force2D for the M values?