GeoTools开发WMS：EPSG4326请求与EPSG2383高斯投影瓦片偏移问题求助

使用GeoTools开发WMS服务，前端请求采用EPSG:4326坐标系，PostGIS数据源存储的是高斯投影坐标（EPSG:2383）。尝试将前端传入的bbox矩形区域从EPSG:4326转换为EPSG:2383后进行视口映射，当瓦片固定为256*256规格时，出现瓦片拼接偏移、线条扭曲的问题。将所有PostGIS数据源转换为EPSG:3857后，以EPSG:3857的bbox请求无偏移，但全量转换数据源的方案不可取。先后尝试自定义坐标转换（含墨卡托转经纬度、四参数转换）及GeoTools原生转换工具，均出现上述问题，寻求无需转换全部数据源的解决办法。

尝试过的代码实现 #

自定义坐标转换核心代码 #

double x1 = getMapDTO.getBbox()[0];
double y1 = getMapDTO.getBbox()[1];
double x2 = getMapDTO.getBbox()[2];
double y2 = getMapDTO.getBbox()[3];
// 先将4326经纬度转为3857墨卡托坐标，再通过四参数转换为2383平面坐标
Point1 = point1.transformMercatorToXy(2383);
Point2 = point2.transformMercatorToXy(2383);
x1 = wpgPoint1.getX();
y1 = wpgPoint1.getY();
x2 = wpgPoint2.getX();
y2 = wpgPoint2.getY();
Double[] box = new Double[]{x1, y1, x2, y2};
getMapDTO.setBbox(box);

mapArea = new ReferencedEnvelope(x1, x2, y1, y2, CRS.decode("EPSG:2383"));
map.getViewport().setBounds(new ReferencedEnvelope(mapArea, CRS.decode("EPSG:2383")));
sr.setMapContent(map);
// 初始化输出图像，width = 256, height=256
BufferedImage bi = new BufferedImage(width, height,
        BufferedImage.TYPE_INT_RGB);
Graphics2D g = bi.createGraphics();
bi = g.getDeviceConfiguration().createCompatibleImage(width, height, Transparency.TRANSLUCENT);
g.dispose();

墨卡托转经纬度方法 #

public static double[] mercator2LonLat(double[] lonLat) {
    double x = lonLat[0] / 20037508.34 * 180;
    double y = lonLat[1] / 20037508.34 * 180;
    y = (180 / Math.PI) * (2 * Math.atan(Math.exp(y * Math.PI / 180)) - Math.PI / 2);
    return new double[]{x, y};
}

四参数转换方法 #

private double[] fourParameterConversion(double x, double y) {
    //四参数指两个坐标参考系间的X轴偏移、Y轴偏移、旋转角、缩放比例
    FourParam fourParam = transformParam.getFourParam();

    double x_off = fourParam.getDx(), y_off = fourParam.getDy(), t = fourParam.getRotate(), m = fourParam.getScale();

    double x1 = x_off + (y * Math.cos(t) - x * Math.sin(t)) * m;
    double y1 = y_off + (x * Math.cos(t) + y * Math.sin(t)) * m;

    double[] xy = new double[]{Math.round(x1 * ROUNDING_FACTOR) / ROUNDING_FACTOR, Math.round(y1 * ROUNDING_FACTOR) / ROUNDING_FACTOR};

    return new double[]{xy[1], xy[0]};
}

GeoTools原生转换代码 #

CoordinateReferenceSystem sourceCRS = CRS.decode("EPSG:4326");
ReferencedEnvelope envelope = new ReferencedEnvelope(x1, x2, y1, y2, sourceCRS);
// 使用 envelope 周围的10个采样点进行转换
CoordinateReferenceSystem targetCRS = CRS.decode("EPSG:2383");
ReferencedEnvelope result = envelope.transform(targetCRS, true, 10);

map.getViewport().setBounds(result);
sr.setMapContent(map);

内容的提问来源于stack exchange，提问作者threecat